Goal

This program performs direct imaging of planets using the coronagraph on MIRI. It focuses entirely on following up known planets that will be discovered using one or more large upcoming ground based surveys (Gemini Planet Imager, VLT/SPHERE, Subaru, Palomar, etc.).

We assume the planets to be known and request tight constraints on the absolute orientation for each target, as well as an immediate 10-degree roll, and an immediate PSF reference star observation. As a result, because of limitations on allowed rolls as a function of ecliptic latitude, it is expected that a number of these observations may not be schedulable.

The goal of this program is to better understand the physical limitations for coronagraphic observations and develop mitigation strategies if necessary, and to define a set of rules to prevent the observer from requesting un-schedulable observations.

The program includes 20 stars to be observed by MIRI in three filters. Theses stars are representative of the possible targets that will be observed by JWST. They include a few well- known targets such as HR8799, Beta Pic, etc., and a few stars selected randomly in several nearby young moving groups (TWA, Beta Pic, Tuc/Hor, Cha Near, AB-Dor etc.).

The 20 targets are split in two groups to test two possible observing scenarios:

• The first group of 10 targets is assumed to have planets at ''large-separations'', which means that a 10 deg roll right away will be sufficient to move the planet off itself on the detector.
• The second group of 10 targets is assumed to have planets at i''small-separations''; which means that a 10 deg roll is not sufficient to move the planet off itself on the detector, but it is sufficient to provide a ''roll-dither'' of the PSF at the pixel level. This second group will be observed with a 10 deg roll (for the roll-dither effect) and then again at a later date to provide a larger roll offset. In this case, both sets of observations have an absolute orientation that is specified. We assume one hour total exposure time per target per filter.

Targets

i) Well known targets

HR8799
Fomalhaut
beta Pic
GQ Lup
2MASSWJ1207334-393254
1RXS J160929.1-210524
UScoCTIO108
CT Cha

ii) TWA moving group

HD 298936
2MASS J12153072-3948426

iii) Beta Pic moving group

HR 9
HIP 92024
HIP 88399

iv) Tuc/Hor moving group

HIP 107947
HD 13183
HD 13246
CD-60 416

v) AB Dor moving group

HIP 6276
HIP 26373

vi) Cha Near moving group

RXJ1239.3-7502

Observing Template

MIRI Coronagraphy

Observation Details

MIRI coronagraphy (First 10 stars, single observations):

i) Target observations in each FQPM coronagraph (with absolute orient)
ii) Immediate Roll 10 degrees and repeat target observations in each FQPM coronagraph
iii) Immediate Slew to reference star and observation in each FQPM coronagraph

MIRI coronagraphy (Last 10 stars, repeated observations for larger roll):

i) Target observations in each FQPM coronagraph (with absolute orient)
ii) Immediate Roll 10 degrees and repeat target observations in each FQPM coronagraph
iii) Immediate slew to reference star and observation in each FQPM coronagraph
iv) Target observations in each FQPM coronagraph with 30-40 degree roll (at later date)
v) Immediate Roll 10 degrees and repeat target observations in each FQPM coronagraph
vi) Immediate slew to reference star and observation in each FQPM coronagraph

Constraints

Specific position angles and some relative timing links.

Parallel Observations Possible (yes/no/pure parallel)?

N/A

Goal

This program performs direct imaging of planets using the coronagraph on NIRCam. The program is designed assuming that it focuses entirely on following up known planets that will be discovered using one or more large upcoming ground based surveys (Gemini Planet Imager, VLT/SPHERE, Subaru, Palomar, etc.).

By choice this program does not include a ''search'' for new planets in this first version. The decision to build this program entirely as follow-ups of known planets is motivated by putting more stress on the scheduling system. Because we assume the planets to be known, we request tight constraints on the absolute orientation for each target, as well as an immediate 10-degree roll, and an immediate PSF reference star observation. As a result, because of limitations on allowed rolls as a function of ecliptic latitude, it is expected that a number of these observations will not be schedulable. The goal is to better understand the physical limitations for coronagraphic observations and develop mitigation strategies if necessary, and to define a set of rules to prevent the observer from requesting un-schedulable observations.

We assume that we know where the planets are located and that we want to avoid certain features of the coronagraph, e.g. the NIRCam coronagraphic wedge. This will be particularly important for observing multiple-planet systems such as the HR8799 four-planet system where the orientation of the wedge has to be carefully chosen to avoid the planets is possible. If/When multiple-planet systems are detected with GPI/SPHERE, they will be highly desirable targets for coronagraphy. For planets at small inner-working angles (also highly desirable targets) an absolute orientation oe the telescope is necessary as well.

Each target star is also associated with a reference star to be observed immediately after the target. The reference stars have been picked loosely to provide a very good match both in magnitude and spectral type. This means that the requested slews can be very large in some cases and large (degrees) in most cases, and it is possible that these observations may not be schedulable. In many cases it should be possible to relax these constraints. For example, with MIRI it is very likely that spectral type matching will not be very important criterion, so that we should be able to use reference stars much closer to the targets in most cases. Again, a range of separations is assumed here to help understand what realistic limitations are for reference star separations.

The program includes 20 stars to be observed by NIRCam in three filters. Theses stars are the same targets as in program 93030 (MIRI) and are representative of the possible targets that will be observed by JWST. They include a few well-known targets such as HR8799, Beta Pic, etc. and a few stars selected randomly in several nearby young moving groups (TWA, Beta Pic, Tuc/Hor, Cha Near, AB-Dor etc.).

The 20 targets are split in two groups to test two possible observing scenarios:

• The first group of 10 targets is assumed to have planets at ''large-separations'', which means that a 10 deg roll right away will be sufficient to move the planet off itself on the detector. (Note: this assumes the initial observation is offset from nominal roll by 5 degrees and then rolled to 5 degrees on the other side of nominal roll for the second observation.) We assume one hour total exposure time per target per filter.
• The second group of 10 targets is assumed to have planets at ''small-separations'', which means that a 10 deg roll is not sufficient to move the planet off itself on the detector, but it is sufficient to provide a ''roll-dither'' of the PSF at the pixel level. This second group will be observed with a 10 deg roll (for the roll-dither effect) and then again at a later date to provide a larger roll offset. In this case, both sets of observations have an absolute orientation that is specified. We assume one hour total exposure time per target per filter.

Targets

i) Well known targets

HR8799
Fomalhaut beta Pic GQ Lup
2MASSWJ1207334-393254
1RXS J160929.1-210524
UScoCTIO108
CT Cha

ii) TWA moving group

HD 298936
2MASS J12153072-3948426

iii) Beta Pic moving group

HR 9
HIP 92024
HIP 88399

iv) Tuc/Hor moving group

HIP 107947
HD 13183
HD 13246
CD-60 416

v) AB Dor moving group

HIP 6276
HIP 26373

vi) Cha Near moving group

RXJ1239.3-7502

Observing Template

NIRCam Coronagraphy

Observation Details

NIRCam coronagraphy (First 10 stars, single observations)

i) Target observations with wedge in three filters (with absolute orient)
ii) Immediate Roll 10 degrees and repeat target observations with wedge in three filters
iii) Immediate slew to reference star and observations with wedge in three filters 1.

NIRCam coronagraphy (Last 10 stars, repeated observations for larger roll)

i) Target observations with wedge in three filters (with absolute orient)
ii) Immediate Roll 10 degrees and repeat target observations with wedge in three filters
iii) Immediate slew to reference star and observations with wedge in three filters
iv) Target observations with wedge in three filters with 30-40 degree roll (at later date)
v) Immediate Roll 10 degrees and repeat target observations with wedge in three filters
vi) Immediate slew to reference star and observations with wedge in three filters

Comments

Specific position angles and some relative timing links.

Goal

This program performs direct imaging of planets using the NRM on NIRISS.

By choice this program does not include a ''search'' for new planets in this first version. The decision to build this program entirely as follow-ups of known planets is motivated by putting more stress on the scheduling system. Because we assume the planets to be known, we request tight constraints on the absolute orientation for each target, as well as an immediate 10-degree roll, and an immediate PSF reference star observation. As a result, because of limitations on allowed rolls as a function of ecliptic latitude, it is expected that a number of these observations will not be schedulable. The goal is to better understand the physical limitations for coronagraphic observations and develop mitigation strategies if necessary, and to define a set of rules to prevent the observer from requesting un-schedulable observations.

Each target star is also associated with a reference star to be observed immediately after the target. The reference stars have been picked loosely to provide a very good match both in magnitude and spectral type. This means that the requested slews can be very large in some cases and large (degrees) in most cases, and it is possible that these observations may not be schedulable. In many cases it should be possible to relax these constraints. For example, with MIRI it is very likely that spectral type matching will not be very important criterion, so that we should be able to use reference stars much closer to the targets in most cases. Again, a range of separations is assumed here to help understand what realistic limitations are for reference star separations.

For NRM observations, we used 9 targets that were provided by the NRM team. These are very well known targets of interest for the NRM observations.

Targets

NRM targets in star forming regions

DM Tau
GM Aur
LkCa 15 (=V1079 Tau) UX TauA (=HD285846)
LkHa 330 (=IRAS 03426+3214)
Em* SR 21 (=2MASS J16271027-2419127)
TW Hya
HD 135344B (=CD-36 10010B)
T Cha

Observing Template

NIRISS NRM

Observation Details

NIRISS NRM (First 5 targets)

i) Target observations with 9-point dither in each three filters (with absolute orient)
ii) Reference observations with 9-point dither in each three filters 2.

NIRISS NRM (Last 4 targets)

i) Target observations with 9-point dither in each three filters (with absolute orient)
ii) Reference observations with 9-point dither in each three filters
iii) Target observations with 9-point dither in each three filters with Roll 30-40 deg (at later date)
iv) Reference observations with 9-point dither in each three filters

Constraints

Specific position angles and some relative timing links.

Goal

Planetary systems do not necessarily die when their stars do. White dwarfs (WDs), the end state for 1-8 M☉ stellar evolution, can show evidence for the presence of planetary systems in orbit around them in the form of infrared excesses due to dust disks and pollution of their atmospheres from the surface accretion of dust grains. The dust disks observed around WDs are most likely caused by the tidal disruption of asteroids a few tens of WD radii away. The asteroids are perturbed by presumed unseen gas giant planets at distances of 5-10 AU. The disks are relatively bright in the infrared and can be characterized in detail at resolutions >10 times better than previously done with Spitzer using the MIRI MRS. The spectra will be used to compare mineral chemistry in the disk with what is accreted onto the WD photospheres in order to determine detailed atomic abundances of dust that participated in terrestrial and giant planet formation. Because of their low luminosity, WDs are excellent targets for direct imaging surveys for giant planets--in the F480M filter of NIRCAM, the contrast of a 5~Gyr 2 MJup planet is 2x10-4, 1x10-4 and 4x10-5 relative to WDs with T eff =5000, 10000, and 25000 K, the range of Teff for WDs within 10 pc of the Sun (Burrows, Sudarsky & Lunine 2003; Bergeron et al., 1996; Holberg et al., 2008).

Nominal Allocation (hours)

50

Targets

WD (Disks):

G29-38
GD 362
GD 56
GD 40
WD 1150-153
WD 2115-560
GD 16
GALEX J1931+0117
GD 133
WD 1015+161

WD (Direct Imaging):

G29-38
WD 0046+051
WD 1142-645
WD 0413-077
WD 0426+588
WD 0752-676
WD 1748+708
WD 0552-041
WD 0553+053
WD 2251-070
WD 1334+039
WD 0839-327
WD 0435-088
WD 1132-325
WD 0738-172
WD 0038-226
WD 0310-688
WD 0245+541
WD 0912+536

Observing Templates

NIRCAM Coronagraphic Imaging
MIRI MRS

Observation Details

The observing strategy will be as follows:

A sample of the brightest 10 WD dust disks (roughly half of currently known disks) will be observed with the MIRI MRS to fully characterize the 5-20 μm spectrum in order to determine dust grain composition, abundances, and disk structure. A 1hr observation per disk (1000 s for G29-38) will ensure S/N>10 for all MRS wavelengths <20 μm assuming a G29-38 analog spectrum scaled to the flux for our dimmest target at 8 μm. We will observe a volume limited sample of WDs (+G29-38, the closest WD dust disk) within 10 pc at 1hr integration/target in the F480M filter and the MASKLWB coronagraphic wedge with PSF Rolls. JWST is sensitive to a 5 Gyr, 2 MJup companion at a S/N > 10 at this distance, provided that the object is not dimmer than 3 times the PSF brightness/pixel. It is assumed that the full sample of WDs can be used as a basis set of PSFs for a variant of the LOCI reduction procedure in conjunction with a coronagraphic mask to ensure sensitivity goals without positional or roll dithers. If roll or position dithers are needed this may increase the required direct observing time. Some targets may not need the use of a coronagraphic mask if detailed contrast calculations show that the desired sensitivity can be obtained with direct PSF subtraction.

Parallel Observations Possible (yes/no/pure parallel)?

No.

Program Coordinator/Date

J.H. Debes/14 December 2011

Goal

The discovery of an earth-like planet around a sun-like star will certainly be deemed as a major milestone in the study of extrasolar planets. Many large efforts, including space missions like Kepler, are currently under way to achieve this goal. The discovery will be most interesting if the host star happens to be bright enough so that the molecular signatures from the atmosphere of such a planet can be detected by JWST.

Since bright host stars will be particularly interesting, let us estimate the brightness of the brightest of such objects. The probability of transit for an earth at 1 AU around a G-type star can be expressed as R☉/a ~ 7 x1010 /1.5 x1013~ 0.5%. Assuming every star has an earth-like planet, the optimal sample size needed to observe the first earthlike planet around a sun-like star is thus ~200. Taking the brightness distribution of known stars, the expected brightness of the first sun- like host of an earth-like planet is V ~ 6. As described in detail by Sahu et al. (Technical Report, JWST-STScI-001999), special configurations can be used to avoid saturation in such bright- target observations.

The JWST observations of this earth analogue include continuous monitoring of the star before, during, and after the transit. We note that the expected transit duration is ~12 hours for a planet with an orbital period of 1 year around a Sun-like star. Since this is a differential observation, the baseline observations outside the transit should preferably have higher S/N than the observations during the transit. One way to achieve this would be to spend equal amount of time during and outside the transit, and use on-chip comparisons. Thus the observations last 36 continuous hours (12 hours during transit and 24 hours outside). Time resolution of ~10 minutes would be desirable to sample the ingress/egress of the transit, and to detect/study occasional passage of the planet over star spots. The observations involve imaging with NIRCam: to get high S/N required for accurate radius determination and determination of inclination angle. Since the timing of the transit is generally known to high accuracy, full time resolution is needed only during ingress and egress. During the main part of the event, sparser time sampling would be adequate.

Nominal Allocation (hours)

36

Target

Kepler 22-b (We use Kepler 22-b as the target, which is an earth-analogue around a fainter star, but we have changed its magnitude to V=6 in anticipation of future discoveries.)

Observing Template

NIRCam Imaging

Observation Details

Observations are carried out for a continuous period of 36 hours: 12 hours before, 12 hours during, and 12 hours after the transit. In the SW, we need to use a weak lens to avoid saturation. In the LW, we need to use the grism for the same reason. We use RAPID readout pattern with N_GROUP=2 and N_INT=460, resulting in 9752 sec of integration time per exposure. We request 8 of these exposures.

Parallel Observations Possible (yes/no/pure parallel)?

No.

Comments

No dithering is possible during exoplanet observations, so while parallel exposures would be quite deep, it would be difficult to correct for detector artifacts. Since exoplanet hosts are typically near the galactic plane, bright stars in the field could give rise to persistence in parallel instruments that are not shuttered.

Program Coordinator/Date

K. Sahu

Goal

Characterize diverse exoplanet properties via differential spectroscopy in and out of transit and eclipse and as a function of orbital phase. Differential spectroscopy constrains stellar mean density, orbital inclination, orbital eccentricity, planetary radius, planetary atmosphere composition, temperature structure, and surface heat redistribution.

Nominal Allocation (hours)

600 hours for all exoplanet observations (program 3040)

Targets

The 23 currently known transiting exoplanet hosts with K band [Vega] magnitude between 5.5 and 9. The list (sorted by decreasing K-band brightness) is:

HD 189733 b
HD 97658 b
GJ 436 b
HD 209458 b
HD 17156 b
HD 149026 b
HAT-P-11 b
HD 80606 b
WASP-33 b
HAT-P-2 b
WASP-38 b
WASP-8 b
WASP-18 b
WASP-7 b
HAT-P-17 b
WASP-14 b
GJ 1214 b
WASP-29 b
XO-3 b
WASP-34 b
HAT-P-14 b
HAT-P-8 b
HAT-P-13 b

The number of targets in this brightness range will likely double between now and the launch of JWST.

Note: Strike-throughs above show targets cut to reduce program size. Additionally, 6 eclipse visits were trimmed from the series on GJ 1214 b.

Observing Template

NIRSpec Fixed Slit Spectroscopy

Observation Details

Each observation begins with a NIRSpec target acquisition into the S1600A1 aperture, which is 1.6 x 1.6 arcsec square. For a well-centered star, this large aperture is relatively insensitive to target drift (due to ISIM thermal changes and/or rotation about the FGS guide star) because the wings of the PSF have dropped roughly symmetrically to relatively low levels at the edge of the aperture.

The standard MSA acquisition will not work because exoplanet hosts are too bright for full-frame NIRCam imaging, so the position of the exoplanet host relative to reference stars cannot be measured precisely enough. A dispersed light acquisition and peakup is needed to acquire exoplanet hosts. In the associated spreadsheet, we assume that this alternate target acquisition will take 15 minutes.

Nominally, a new target acquisition is required after 10,000 seconds to compensate for target drift and to allow the observatory an opportunity to repoint the antenna. Repeating target acquisition may affect precise calibration more than target drift, so here we assume only one target acquisition per observation.

After target acquisition, 1-5 exposures will be obtained with minimum interruption between. Each observation will consist of hundreds to thousands of integrations. Each integration will have 2-38 groups, tuned to approach but not exceed saturation of the detector A/D converter. By rule individual exposures will not exceed 10000 seconds, but longer exposures would be useful. Exposure times are adjusted below this maximum to avoid exposure breaks near ingress or egress.

Transiting planets have well-defined ephemerides. Most known exoplanets have orbital periods of one to several days, implying tens of scheduling windows per year. Visits do not have an orientation constraint.

Given the flexibility of event-driven observations, the observatory may be ready to execute an exoplanet visit before the nominal start time. As soon as the preceding visit completes, the observatory should slew from the old attitude to the exoplanet-observing attitude. Slewing immediately allows slew-related mechanical and thermal transients to decay as much as possible before the high-precision exoplanet observation begins. The observer will be charged (at least statistically) for the time spent by the observatory waiting for the exoplanet transit or eclipse window to occur. The associated spreadsheet assumes an overhead of 15 minutes per observation, waiting for the observation to begin.

Transit observations will generally be obtained at short wavelengths where the star is bright, except where going to longer wavelengths is necessary to avoid saturation (e.g., HD 189733). Eclipse observations will be obtained at long wavelengths, where the planet is brighter and the star is fainter. Exposures will be obtained with high-resolution gratings to resolve spectral features, allow binning in wavelength to mitigate detector artifacts, and to increase slightly the bright limit. Thus, the nominal grating and filter combinations will be G140H/F100LP for transits and G395/F290LP for eclipses.

Exposures will be obtained with a 2048 x 32 pixel subarray. Spectra will curve on the detectors, but 32 pixels should be enough to record spectra from a point source well centered in the aperture.

Because exoplanet hosts are bright, integrations will saturate after only a few frames. The NRSRAPID detector pattern (one frame per group, i.e. NFRAMES=1) will be used to record as many groups as possible without saturating. [Note: the A/D converter saturates at 64k ADU before charge fills the pixel wells.] Because the data rate for a subarray is 25% the data rate for a full-frame, NRSRAPID can be used indefinitely without exceeding the NIRSpec data volume allocation.

Constraints

Every visit has a PERIOD, ZERO-PHASE, and PHASE special requirement. Periods are one to several days, so there will typically be many scheduling opportunities per year. ObsGroup1 has a transit observation and an eclipse observation for 23 different exoplanets spread over the entire sky, each with a different ephemeris. ObsGroup2 has 32 eclipse observations of the same exoplanet to build S/N, requiring many large slews to and from this target. ObsGroup3 has 3 phase curve observations that span one transit and one eclipse, requiring visits that are 16-24 hours in duration.

Parallel Observations Possible (yes/no/pure parallel)?)

No dithering is possible during exoplanet observations, so while parallel exposures would be quite deep, it would be difficult to correct for detector artifacts. Since exoplanet hosts are typically near the galactic plane, bright stars in the field could give rise to persistence in parallel instruments that are not shuttered.

Program Coordinator/Date

J. Valenti, B. Blair/7 March 2012

Goal

This project is to determine the frequency of hot earths in a given population. We note that the expected transit depth caused by a hot earth (R ~ 3 R⊕) is ~ 0.1%, the expected transit duration is ~ 3 hours, and the expected orbital period is 1 to 5 days. We also note that for the minimum pixel-by-pixel reset+read time of (10.6+10.6=) 21.2sec, using F150W filter, saturation will be just avoided for stars with V ~17 for a G-type star. This is close to the turn-off magnitude for NGC 6791, making this an ideal target.

A reasonable way to achieve this goal therefore, is to monitor a nearby, rich, high-metallicity cluster, such as NGC 6791 ([Fe/H] ~ +0.4). The expected observations will be similar to the SWEEPS program towards the Galactic bulge (Sahu et al. 2006) or the 47-Tuc monitoring program (Gilliland et al. 2001), where a rich stellar field was monitored continuously for about about a week. Hot-earths can be detected with 10-sigma detection in such an observational scenario. Monitoring of 2000 to 5000 stars can potentially lead to the detection of ~20 hot earths (where we assume that 10% of the earth-size planets are ''hot earths'', and 10% of them transit), perhaps further boosted by the higher metallicity of the cluster. Being able to reach to a few Earth radii as the limit for planet size, and determining the frequency of such planets would certainly be worthwhile experiment that is likely to be carried out with JWST.

Since the expected transit duration is ~ 1 to 3 hr, the observations need to be continuous so that no transits will be missed. The observations should be preferably carried out in 2 filters, which serve as a guard against astrophysical false positives (such as star spots and binaries), as demonstrated by the SWEEPS data.

We note that ICDH [ISIM (Integrated Science Instrument Module) Command and Data Handling] hardware is capable of co-adding up to 16 frames (in powers of 2) of a maximum of 5 SCAs. Since we need to monitor a large number of stars, 5 detectors need to be used simultaneously for the monitoring program.

Nominal Allocation (hours)

105

Target

NGC 6791

Observing Template

NIRCam Imaging

Observation Details

Observations are carried out for a continuous period of 105 hours. We use RAPID readout pattern with N_GROUP=2 and N_INT=460, resulting in 9752 sec of integration time per exposure. 38 such exposures can be taken in 105 hours.

Parallel Observations Possible (yes/no/pure parallel)?

Possible to do parallel observations with NIRISS which will increase the efficiency of the detection of hot Earths.

Program Coordinator/Date

K. Shau/3 January 2012

Goal

The primary goal of this program is to characterize a few interesting exoplanets, with an emphasis on giant, Neptune-sized, and mini-Neptune planets. Planets as small as Earth with M star hosts may also be good targets if they have H-dominated (large scale height) atmospheres. Mid-IR imaging and spectroscopy in and out of transit and eclipse, and as a function of orbital phase, will be used to determine (i) the average temperatures and profiles, (ii) surface temperatures , (iii) atmospheric compositions, and (iv) heat transfer of the exoplanets.

Nominal Allocations (hours)

40

Targets

We use the currently known list of transiting exoplanets for our targets (203 transiting planets). These do not include and Earth-sized planets observable with JWST, but we hope and expect that such planets will be discovered in the coming years. We have chosen targets that span a variety of masses, surface gravities, stellar insolations, and are likely to show spectral features that would be useful in diagnosing their atmospheric compositions, temperature profiles, and thermal emissions/heat transfer in a single transit or eclipse observation.

The details of the targets are given in table 1. The first 9 in the list are slitless LRS and the last one is a photometric observation. The Table also lists the transit and eclipse durations, which are in the 1 - 3 hour range.

Constraints

Every visit has a PERIOD, ZERO-PHASE, and PHASE special requirement. Periods are one to several days, so there will typically be many scheduling opportunities per year.

Parallel Observations Possible (yes/no/pure parallel)?

The whole program could in principle be done with a parallel program deep imaging program.

Program Coordinator/Date

K. Sahu, T. Greene

Goal

The identification and characterization of planets in star-forming regions can uniquely address several important questions. Looking for such newborn planets is the only way to uncover a pristine planet population, unaffected by dynamical evolution that is expected to occur over the first tens of Myr. This primordial population is a direct tracer of the planet formation mechanism. Also, by comparing results in star-forming regions with results from studies of older stars, this further allows studying the dynamical evolution process itself. The study of planets at these young ages also allows probing the timescale for planet formation, expected to be 1-10 Myr for giant planets. Also, the ability to study planets at a well-established age in a regime where evolution models are poorly constrained is useful to calibrate the evolution models and understand the early evolution of giant planets.

The goal of this proposal is to find young gas giant planets at 10-50 AU around stars of various masses in the Taurus star-forming region (1-2 Myr, ~150 pc). The proposed NRM observations will typically be >50% complete for planets of >1 MJup at >10 AU. Because of the optical faintness of the target stars, these observations will not be possible from the ground using extreme adaptive optics systems.

Actual Time (hours)

180 hours (150 hours for the first observation of the 100 targets, plus 30 hours for the follow-up of ~5 planets in two 100 targets, plus 30 hours for the follow-up of ~5 planets in two additional filters).

Targets

100 stars (~0.2-1.5 Msun) in Taurus. Typical M band magnitudes between 7 and 11. The coordinates of all targets are magnitudes between 7 and 11. The coordinates of all targets are close to RA=4h40, DEC=+25.

Observing Template

NIRISS NRM

Observation Details

The initial observations for this project would be made in only one of the three red medium band filters of NIRISS, likely F430M. A typical observing sequence would be the following.

1. Select NRM element
2. Select desired filter
3. Perform a Target Acq
4. Repeat 9-25 times
4.1. Take several exposures
4.2. Dither

The observations will use either the 256x256 or 512x512 subarrays with the TFIRAPID or TFI readout patterns, depending on the target magnitude. Each target will be observed at 9 (up to 25) dither positions, and at each position several exposures will be acquired successively, always keeping the brightest PSF pixel close to but below 70000 electrons. Each observing sequence will amount to 90 minutes total (clock time).

Any planet detection made will require follow-up observations the other two filters for characterization. The observing approach will be identical to above.

Constraints

NRM observations require the observations of calibrator stars, ideally of similar spectral type and brightness, stars, ideally of similar spectral type and brightness, and to be acquired close in time. For this program, these calibrators will be other targets from the program, so it would be good when possible to plan observation of two or three targets successively in a group.

Parallel Observations Possible (yes/no/pure parallel)?

Yes.

Comments

For the spreadsheet, 100 targets were selected from Luhman et al. 2010, ApJS, 186, 111 with RA between 67<RA<72 degrees and 23<Dec<27 degrees. Coordinates and K band mags were grabbed from SIMBAD, and acquisition fluxes were computed from the K band magnitudes assuming 0 color correction. Target acquisition is put in with F430M for all the targets and just a single ramp. SUB128 is used if the target was brighter than K=9 and SUB256 if the target is fainter. The number of reads and iterations is set to give a total exposure time of 3600s for each source and have no more than 30 reads, where the number of reads was taken to be INT(10-0.4(M-K)) with M=8 for SUB256 and M=6.6 for SUB128. This is just a rough guess to provide some variety in the readout subarrays and NINTS so that any data volume studies have some semi-realistic variety. Every source is viewed at 25 dither positions.

Three additional fake reference stars were added, and linked so that a given reference is used for 10 successive targets. There should be no telescope rephrasing between target and reference. Coordinates and K band mags were grabbed from SIMBAD, and acquisition fluxes were computed from the K band magnitudes assuming 0 color correction.

This program is a clear candidate for "cluster targets," since the stars are all relatively close together.

Program Coordinator/Date

D. Lafrenière, H. Ferguson/21 March 2012

Goal

New instruments specialized for direct exoplanet imaging will begin operation in the next year or so. Probably the two most important such instruments are the Gemini Planet Imager (GPI) and the Spectro-Polarimetric High-contrast Exoplanet REsearch instrument (SPHERE, for the VLT). These instruments will probe angular separations of 0.1''-1'' at very high contrast (10-7:1) and detect and characterize giant exoplanets at wavelengths of 1.0-2.5μm. Both GPI and SPHERE will be mostly used for large campaigns, to occur over the 2013-2018 periods, and will be over when JWST begins its operation. Monte Carlo simulations indicate that these two main surveys should uncover about 100 new planets with masses of 1-10 MJup and semi-major axes of 5-40 UA.

These new planets will have been well characterized over 1-2.5 5μm, the operating wavelength range of both instruments, but not at longer wavelengths. However, the 2.5-5.0μm region contains a significant fraction of the planets flux and is quite important for atmospheric characterization and accurate luminosity measurements. At Lâ, ground-based NRM observations can reach contrast of 7-8 mag and a limiting magnitude of about 14, insufficient to detect most planets. The long wavelength characterization of the GPI (and SPHERE) planets will thus likely be impossible to accomplish from the ground. Many of the GPI (and SPHERE) planets will be inside the IWA of the JWST coronagraph, and thus will be observable with JWST only with the NIRISS NRM. This proposal is to do precisely that: acquire photometric measurements at 3.8-4.8 microns for giant planets previously discovered from the ground but uncharacterized at long wavelengths.

Actual Time (hours)

75 hours (15 targets, each target observed for 2 hours in three filters, plus observations of 5 calibrators).

Targets

15 planets detected by GPI or SPHERE that fall inside the IWA of the NIRCam coronagraph and have expected contrasts within the reach of NIRISS NRM at ~4 microns. The target magnitudes at L and M will be between 5 and 8.5. The targets will be spread across the whole range of right ascension and will be at declinations below +20.

Observing Template

NIRISS NRM

Observation Details

A typical observing sequence would be the following:

1. Select NRM element
2. Select desired filter
3. Perform a Target Acq
4. Repeat 9-25 times
4.1. Take several exposures
4.2. Dither
5. Switch filter
6. Go back to 3.

The observations will use either the 128x128 or 256x256 subarray with the TFIRAPID readout patterns. Each target will be observed at 9 dither positions, and at each position several exposures will be acquired successively, always keeping the brightest PSF pixel close to but below 70000 electrons. Each observing sequence in a given filter will typically amount to 2 hours total (clock time).

The observations will be repeated in three filters (F380M, F430M and F480M) for each target. In addition to the targets, 5 calibrator stars will be observed using identical sequences.

Constraints

NRM observations require the observations of calibrator stars, ideally of similar spectral type and brightness, and to be acquired close in time. For this program, we plan on having 5 such calibrators for the 15 targets, so the same calibrator will be used for about 3 targets. Thus it would be good to plan observations in groups of four (three targets plus one calibrator).

This strategy may or may not be practical given the limited field-of-regard of JWST.

Parallel Observations Possible (yes/no/pure parallel)?

Yes.

Comments

For the spreadsheet, random stars with 7<V<9.5 and 6.5<K<10 were selected with dec < +20. Each filter was given 1800s of exposure time. Target acquisition is put in with F430M for all the targets and just a single ramp. The number of reads was taken to be INT(10-0.4(M-K)) with M=6.6 for SUB128. Given the limiting magnitudes for GPI and SPHERE, small subarrays are probably going to keep the readout times short enough. The spreadsheet has strawman timing links between targets and reference stars that probably will not work in practice given the JWST field of regard.

Program Coordinator/Date

D. Lafrenière, H. Ferguson/21 March 2012

Goal

In the next few years ground-based imaging surveys for exoplanets will mainly probe solar or higher mass stars, as they are brighter and thus amenable to extreme adaptive optics observations. These surveys will fully bridge the gap in semi-major axis with indirect techniques and provide a complete picture of the giant planet population around solar and higher mass stars. The giant planet populations at large separations (few to tens of AUs) around low mass stars will remain unconstrained however, as they are too faint for extreme adaptive optics observations.

Fortunately, it will be possible to observe these stars with the NIRISS NRM and search for planets in the relevant regime of mass and semi-major axis. This will allow us to determine how often and where do gas giants form around low-mass stars compared to more massive ones, which in turn will greatly help us understand the planetary formation process. NIRISS NRM will be able to detect planets of 1-3 MJup at separations of 3-20 AU around young (10-100 Myr) nearby (10-75 pc), low-mass stars (0.1-0.5 Msun). Thus NIRISS NRM offers a good, and possibly the only, means of probing the same orbital separation for low-mass stars as specialized ground-based instruments (GPI/SPHERE) will probe for more massive stars. In addition, these observations might have the sensitivity to detect molten rocky planets afterglow, following a collision by a large planetesimals.

Actual Time (hours)

75 hours (50 targets, each target observed for 90 minutes in one filter)

Target(s)

50 young M stars (10-100 Myr, 0.1-0.5 Msun) spread across the sky. Typical M band magnitudes between 7 and 11.

Observing Template

NIRISS NRM

Observation Details

The initial observations for this project would be made in only one of the three red medium band filters of NIRISS, likely F480M. A typical observing sequence would be the following:

1. Select NRM element
2. Select desired filter
3. Perform a Target Acq
4. Repeat 9-25 times
4.1. Take several exposures
4.2. Dither

The observations will use either the 256x256 or 512x512 subarrays with the TFIRAPID or TFI readout patterns, depending on the target magnitude. Each target will be observed at 9 (up to 25) dither positions, and at each position several exposures will be acquired successively, always keeping the brightest PSF pixel close to but below 70000 electrons. Each observing sequence will amount to 90 minutes total (clock time).

Constraints

NRM observations require the observations of calibrator stars, ideally of similar spectral type and brightness, stars, ideally of similar spectral type and brightness, and to be acquired close in time. For this program, these calibrators will be other targets from the program, so it would be good when possible to plan observation of two or three targets successively in a group.

Parallel Observations Possible (yes/no/pure parallel)?

Yes.

Comments

For the spreadsheet, SIMBAD was used to select M stars with high proper motions and/or parallaxes, and with 7.5<K<11. These were then grouped by RA & Dec, and a guess was made as to which might be able to be observed at the same time. There were 6 in the that did not have other nearby targets in the list, so 6 reference stars were made up with positions within about 2.5 degrees of each of those targets. Target acquisition is put in with F480M for all the targets and just a single ramp. SUB128 is used if the target was brighter than K=9 and SUB256 if the target is fainter. The number of reads and iterations is set to give a total exposure time of 4320s (90 minutes on target at 80% efficiency) for each source and have no more than 30 reads, where the number of reads was taken to be INT(10-0.4(M-K)) with M=8 for SUB256 and M=6.6 for SUB128. This is just a rough guess to provide some variety in the readout subarrays and NINTS so that any data volume studies have some semi-realistic variety. Every source is viewed at 25 dither positions.

Program Coordinator/Date

D. Lafrenière, H. Ferguson/21 March 2012

Goal

Over the next few years, based on large campaigns such as SPIROU (near-infrared radial velocity survey), it is highly likely that a few transiting, habitable Earth-like planets will be found. The atmospheric composition of those planets can be probed with NIRISS transit spectroscopy (0.6-2.5μm simultaneous coverage), and molecules such as H2O and CO2 could potentially be detected. This proposal is to observe the most favorable of these transiting habitable Earth-like planet to characterize its atmosphere. The goal is to reach a 1σ accuracy of 10 ppm per resolution element at a resolving power of 150, sufficient to detect H2O with confidence.

Actual Time (hours)

138 hours (2 target observed 12 times each for 5.75 h per visit)

Given the parameters of the star and planet (see below), a S/N of 13500 is reached per resolution element at R=700 for each visit, equivalent to a S/N of 29000 at R=150. To reach the goal of 105 at R=150, 12 visits are needed.

Targets

2 M dwarfs harboring a transiting Earth-like planet. Such targets are still unknown but for this exercise we assume the targets to be 0.25 M☉ stars (~M4-M5), for which the habitable zone is at separation ~0.1 AU (orbital period 23 days); we assume that the planet lies precisely at this separation. At 10 pc, the targets would have V=12 and J=9. Assuming that they are to be found with SPIROU, they would have a northern declination.

Given this stellar mass and planet semi-major axis, assuming a circular orbit, the transit duration would be 2.54 h for the flat part (T23), and 2.69 h for the full transit (T14). The transit depth would be 0.0008.

Observing Template

NIRISS G700XD

Observation Details

The observations will begin with a target acquisition to position the star precisely at a predefined location (specific to G700XD observations) on the array. Then the G700XD element will be inserted into the beam. We assumed 15 minutes are needed to complete this.

A long, uninterrupted sequence of several exposures will then be acquired spanning 5.5 hours and approximately centered on the mid-transit time. To keep the maximum pixel signal below 50000 e-, the individual exposure time will be 31.8 s (26.5 s effective integration time), using the 256x2048 subarray (tframe =5.3 s) with TFIRAPID readout and Ngroup =6. Accounting for overheads, each exposure will require 40 s. For the 5.5 h sequence, a total of 495 exposures will be required. No dithers will be performed.

This observing mode requires the observation of calibrators, likely bright white dwarfs with a well-modeled spectrum, to monitor the flat field and wavelength solution. These observations need not be done every time a target is observed, but only once a month or so as a baseline calibration for the observatory. We did not account for the time needed for this calibration here.

Constraints

The observations must be scheduled such that the middle of the sequence occurs within about 1 hour of the mid-transit time. Over a 1.5 year period, there will be 23 transit events per target; 12 of those need to be observed.

Parallel Observations Possible (yes/no/pure parallel?)

Yes, but no dithers possible.

Program Coordinator/Date

D. Lafrenière, H. Ferguson/5 April 2012

Goal

Characterize the atmosphere (composition and structure) of several exoplanets using NIRISS transit spectroscopy, which provides a 0.6-2.5μm simultaneous coverage with a resolving power of 700. For these observations, the goal is to reach a S/N or 10000 per resolution element for differential in/out of transit spectroscopy.

Actual Time (hours)

125 hours (15 targets, each observed for 2X the transit duration, four are observed twice, one is observed 4 times).

Target(s)

15 transiting exoplanet systems: the five brightest systems with a hot Jupiter (0.1-2 MJup), the five brightest with a hot Neptune (10-30 M⊕), and the five brightest with a hot super-Earth (2-10 M⊕). Targets brighter than J=7 are not considered as they would saturate the array.

With the current sample of known exoplanets, the targets would be for hot Jupiters:

HD 149026 b
WASP-7 b
HAT-P-8 b
HAT-P-1 b
HAT-P-30 b

Hot Neptunes:

Kepler-21 b
HAT-P-11 b
Kepler-10 c
HAT-P-26 b
Kepler-19 b

Super-Earths:

Kepler-10 b
CoRoT-7 b
GJ 1214 b
Kepler-20 b
Kepler-11 e

The desired S/N can be reached for all but 5 targets in a single visit. For Kepler-19 b, CoRoT-7 b, GJ 1214 b, and Kepler-20 b, two visits will be needed, while for Kepler-11 e 4 visits will be needed.

Observing Template

NIRISS G700XD

Observation Details

The observations will begin with a target acquisition to position the star precisely at a predefined location (specific to G700XD observations) on the array. Then the G700XD element will be inserted into the beam.

A long, uninterrupted sequence of several exposures will then be acquired spanning twice the transit duration (to get sufficient off-transit baseline coverage) and approximately centered on the mid-transit time. Individual sequences will typically last for 3-6 hours. The maximum pixel signal will be kept below 50000 e- by adjusting the individual exposure times. The 256x2048 subarray (tframe =5.3 s) will be used with, typically, a TFIRAPID readout mode.

This observing mode requires the observation of calibrators, likely bright white dwarfs with a well-modeled spectrum, to monitor the flat field and wavelength solution. These observations need not be done every time a target is observed, but only once a month or so as a baseline calibration for the observatory. We did not account for the time needed for this calibration here.

Constraints

The observations must be scheduled such that the middle of the sequence occurs within about 1 hour of the mid-transit time. The orbital periods of the target planets are a few days at most, so there are plenty of opportunities for observations.

Parallel Observations Possible (yes/no/pure parallel)?

Yes, but dithers are not possible.

Comments

The deired time for each source was set to 30ks * 10(0.15*(K-9.1)) where K is the K magnitude either taken from 2MASS or a guess from a V mag. For some sources, the total integration can not be reaed in a single transit, so the observations are pread over multiple transits, taking the time per transit to be twice the transit duration. Visits of more than 10ks duration were broken up into equal chunks of integration time. The number of reads was taken to be 10(-0.4*(7-K)) for G700sub and 10(-0.4*(5.5-K)) for G700sub4, with a minimum of 1 read before going to the smaller subarray. The resulting number of transits, visits per transit, and the readout pattern are listed in the table below. For the phasing, of the observations, a random fraction of the period was added to JD 2458547.5, and the phase start and end were set to encompass twice the transit duration.

Program Coordinator/Date

D. Lafrenière, H. Ferguson/5 April 2012

Goal

Characterize the emission spectrum of hot Jupiters as a function of orbital phase with NIRISS spectroscopy (0.6-2.5μm simultaneous coverage with a resolving power of 700). This will inform us about the planet temperatures, atmosphere structure, heat redistribution, and composition. For these observations, the goal is to reach a S/N or 30000 per resolution element for each visit.

Actual Time (hours)

95 hours (5 targets, each observed 6 different orbital phases)

Targets

5 brighest stars (with J>7) with a transiting hot jupiters: HD 149026, HD 17156, WASP 33, HAT-P-2, and WASP-18.
The desired S/N can be reached in 1.1, 1.1, 1.7, 2.1 and 3.6 hours for the above targets, respectively.

Observing Template

NIRISS G700XD

Observation Details

The observations will begin with a target acquisition to position the star precisely at a predefined location (specific to G700XD observations) on the array. Then the G700XD element will be inserted into the beam.

A long, uninterrupted sequence of several exposures will then be acquired; the corresponding times are given above. The maximum pixel signal will be kept below 50000 e- by adjusting the individual exposure times. The 256x2048 subarray (tframe=5.3 s) will be used with a TFIRAPID readout mode.

Each target will be observed at 6 different orbital phases, one of which will coincide with the primary transit and one with the secondary eclipse. For the observation covering the primary transit and secondary eclipse, the sequence duration will be modified to last for twice the transit/eclipse duration, such that differential spectroscopy can be done.

This observing mode requires the observation of calibrators, likely bright white dwarfs with a well-modeled spectrum, to monitor the flat field and wavelength solution. These observations need not be done every time a target is observed, but only once a month or so as a baseline calibration for the observatory. We did not account for the time needed for this calibration here.

Constraints

The observations must be scheduled such that the middle of the sequence occurs within about 1 hour of the mid-transit time.

Parallel Observations Possible (yes/no/pure parallel)?

Yes. but dithers are not possible.

Comments

For the spreadsheet, the desired time for each source was set to 2x the transit duration for both eclipse and transit. For the other phases, it was set to 1.1, 1.1, 1.7, 2.1 and 3.6 hours, respectively, for the different targets. Visits of more than 10ks duration were broken up into equal chunks of integration time. The number of reads was taken to be 10(-0.4*(7-K)) for G700sub and 10(-0.4*(5.5-K)) for G700sub4, with a minimum of 1 read before going to the smaller subarray. The resulting exposure times and readout patterns are listed in the table below. For the phasing, of the observations, a random fraction of the period was added to JD 2458547.5, and the phase start and end were set to encompass 1.2 times the exposure time (to account for overhead), centered on the desired phase.

Program Coordinator/Date

D. Lafrenière/5 April 2012