Illegal selection: 23. Couldn't identify "EXTRA-SOLAR PLANETS" as a legal selection. Science Keywords: Select from 2 to 5 items. Science Keywords: Extra-Solar Planets, Planetary Atmospheres and Terrestrial Planets are not valid selections. Cannot find file /Documents/Proposals/Current/TRAPPIST-1/Scientific_Justification.pdf This is a Mid-Cycle proposal 1246765892 Assigned ID: 1252 ----- Attempting Submission 1 (Fri Jan 29 12:17:47 GMT 2016) ----- I have updated the slit from 52x0.05 to 52x0.05 D1 in the ACQ/PEAK and SCI exposures. -1032497754 ----- Attempting Submission 1 (Thu Mar 31 11:43:45 GMT 2016) ----- ----- Attempting Submission 2 (Wed Apr 06 21:00:15 GMT 2016) ----- ----- Attempting Submission 3 (Thu Apr 21 12:58:14 GMT 2016) ----- ----- Attempting Submission 4 (Fri Oct 28 07:14:48 GMT 2016) ----- We just discovered 3 short-period Earth-sized planets transiting a nearby ultracool dwarf star. The inner two planets receive four and two times Earth irradiation, placing them close to the inner edge of the habitable zone. With equilibrium temperatures between 250 - 400 K these planets likely present habitable regions, but the sustained activity of M dwarfs over hundreds of millions of years could impact their habitability. The system proximity (12 pc), its large planet-to-star radii ratios and high systemic velocity (-56 km/s) make it an amazing target to study the state and evolution of terrestrial planets atmospheres around a late M dwarf in the UV. Yet large uncertainties in the strength of M dwarfs Ly-alpha emission and hydrogen escape from small planets make it difficult to plan an efficient HST program to make such measurements. We thus propose a 4-orbit reconnaissance study to determine how HST unique UV capabilities can be optimally employed to observe this important exoplanet system in next cycles. Here we will observe the star with STIS at Ly-alpha to 1) try and measure the stellar line, and 2) search for signatures of hydrogen escape from the planets, which would hint at evaporating water oceans. Because several orbits remain possible for the third discovered planet, we will ensure the best scientific by focusing on the two inner ones. Objective (1) will be achieved by observing the star twice, ensuring that the signal is high enough to constrain the intrinsic Ly-alpha emission. Objective (2) will be achieved by observing the transit of each of the two inner planets, allowing us to detect possible absorption of the stellar line caused by hydrogen exospheres With this program, we will use the four allocated HST orbits to observe the TRAPPIST-1 star at Lyman-alpha wavelengths. This close (12pc) ultracool dwarf hosts two transiting planets 'b' and 'c'. Our goals are (a) to measure how bright the star is at Lyman-alpha and (b) to assess whether escaping gas from the planet is causing very deep Lyman-alpha eclipses of the star. We define three visits: Visit #01 (two HST orbits) will be scheduled at times when both planets are within respective orbital phases 0.5 to 0.85. The goal is to measure the strength of the intrinsic stellar Lyman-alpha line, unabsorbed by the putative exospheres trailing behind the planets. This visit must be scheduled before the two others. Visit #02 (one HST orbit) will be scheduled at the time of planet 'b' transit, with the additional constraint that planet 'c' is within orbital phase 0.5 - 0.85. This will allow the measurement of a possible absorption signature from planet 'b' exosphere, with no contribution from planet 'c' exosphere. Similarly, visit #03 (one HST orbit) will be scheduled at the time of planet 'c' transit, with the additional constraint that planet 'b' is within orbital phase 0.5 - 0.85. It is possible that the star is faint at Lyman-alpha. This would make difficult the measurement of absorption from the planets' exospheres. If Visit #01 shows a faint emission at Lyman-alpha, we will reschedule Visits #02 and #03 with the same phase constraints as Visit #01, so that the four orbits of our program can be coadded to better constrain the stellar Lyman-alpha emission. We would like to request that our program be switched to available mode, so that the AUTO-WAVECAL can be moved to GO-WAVECAL during Earth occultation. Since each visit has a different objective, every minute that can be gained for the scientific exposure would be very useful, in particular because the star is faint, and the ACQ-PEAK takes a relatively long time to perform. In the present case, moving the wavecal during occultation would correspond to a gain of 4.4 mn. This has been done for past programs obtained by our team in agreement with the STScI (GO#13820 and #12681, PI: D. Ehrenreich; GO#14143, PI: V. Bourrier). EXTRA-SOLAR PLANETS 12 false true false false false false AVAILABLE STAR EXTRA-SOLAR PLANETARY SYSTEM We measured the J2000 equatorial coordinates of TRAPPIST-1 in the 2015 TRAPPIST images, using 29 stars from the UCAC2 catalog and the Pulkovo Observatory Izmccd astrometric software (we use the mean epoch of these observations secured between September and December 2015). We adopt uncertainties on RA and Dec as those for 2MASS for this object. We checked that the input coordinates and those given in SIMBAD at Epoch 2000 yield the same position in the APT target confirmation chart at Epoch 1991.68. We also checked independently that these coordinates and proper motion match with the position of the star in POSS image (1953) and 2MASS image (1998). Radial velocity comes from Barnes et al. 2014 TRAPPIST-1 J2000 J2000 V=18.80+-0.08, R=16.47+-0.07, I=14.0+-0.1, J=11.35+-0.02, K=10.30+-0.02 STIS/FUV-MAMA Spectroscopic No No G140M 1222 STIS/FUV-MAMA Spectroscopic No No G140M 1222 STIS/FUV-MAMA Spectroscopic No No G140M 1222 STIS/FUV-MAMA Spectroscopic No No G140M 1222 1477638841798 The scheduling data was generated by CASM 24.2. CASM was run in Phase II mode. /private/var/folders/33/rs56p2wx5q174bfyvvm_nq1m0000gn/T/OPVisit7488466490720145793.xml This visit must be obtained far from the time of transit of either planets TRAPPIST 1b and 1c, to provide a clean estimate of the baseline UV flux from the star. Experience from GJ436b (GO #12965) suggests that, in an extreme case, it might be possible for Ly-alpha to be absorbed from the phase of transit all the way to anti-transit. We indicate in the timing requirements specific time windows, obtained by requiring that boths planets are between (respective) orbital phases 0.5 to 0.85. Observations can start at any time between the given UTC times. We cannot provide phase constraints common to all epochs, because the two planets will be at different orbital phases in each epoch. Except for one earlier epoch, the target visibility with HST as indicated in the Visit Planner is mostly limited to (end of September 2016 - end of January 2017). We provide all possible windows for October and November 2016, and will provide more if no observations can be scheduled by then. 1474856945000 69.43210754951431 (Tic-Visit :proposal-id 14493 :visit-id "01" :proposal-version -1 :trans-version "20160601" :date "28-Oct-2016 09:14:01.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 452784 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14493 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14493 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2880 :al-overhead-at-end 0 :internal-dur-at-end 320 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3213 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14493 :visit-id "01" :orbit-number 2 :pcs-time 222 :si-vis-utilization 2991 :al-overhead-at-end 0 :internal-dur-at-end 639 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3213 :pcs-gap 0 ) true 2 0 We use the F28X50LP filter for this ACQ image, as recommended for this star with V magnitude of 18.8. It also ensures the brightness is weighted most strongly toward red wavelengths, where the target star is brightest. We estimated the exposure time for several stellar models close to the target star (STIS.ta.781640, STIS.ta.781641, STIS.ta.781643). Exposure times to reach a SNR of 40 range from 1.5 to 3.6s, and minimum saturation time is 290s. We thus choose an exposure time of 5s. We used Aladin to check that the closest star is at a distance of more than 220 arcsec. There is thus no chance that STIS acquires another object in the 5x5 arcsec search area. The ETC lists a time to saturation through the 52X0.05 slit of 1086s (for a black body model with the same temperature as the star). With our 10s exposure, we should reach 5600 source electrons, above the 5000 required for peak-up with the mirror element. The target star is a M8 ultracool dwarf from which we expect a much lower emission at Lyman-alpha than from GJ436 targeted in program GO#12965 (in the GJ140M spectral range, the stellar emission from these stars will arise from the Lyman-alpha line alone). We can thus use safely the same settings as program GO#12965. The ETC lists a time to saturation through the 52X0.05 slit of 1086s (for a black body model with the same temperature as the star). With our 10s exposure, we should reach 5600 source electrons, above the 5000 required for peak-up with the mirror element. The target star is a M8 ultracool dwarf from which we expect a much lower emission at Lyman-alpha than from GJ436 targeted in program GO#12965 (in the GJ140M spectral range, the stellar emission from these stars will arise from the Lyman-alpha line alone). We can thus use safely the same settings as program GO#12965. 1477638843105 The scheduling data was generated by CASM 24.2. CASM was run in Phase II mode. /private/var/folders/33/rs56p2wx5q174bfyvvm_nq1m0000gn/T/OPVisit6399664378471751180.xml This visit targets the transit of planet TRAPPIST 1b, and we indicate relevant lower/upper phase constraints in the ACQ subexposure. Furthermore, the visit should be obtained at a time when planet TRAPPIST-1c is far after its own transit, so as not to contaminate the observation of planet 'b' transit. We thus indicate in the timing requirements the windows when planet 'b' transits and planet 'c' is between orbital phases 0.5 to 0.85. Finally, we also request that visit 2 be scheduled at least 15 days after visit 1. The first opportunity for visit 1 being on 16 June 2017, we thus provide all possible opportunities for visit 2 starting at least 15 days after this date, and until the end of November 2016. 1475274741000 68.9282524617461 (Tic-Visit :proposal-id 14493 :visit-id "02" :proposal-version -1 :trans-version "20160601" :date "28-Oct-2016 09:14:02.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 226608 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14493 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14493 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2880 :al-overhead-at-end 0 :internal-dur-at-end 639 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3213 :pcs-gap 0 ) true 1 0 We use the F28X50LP filter for this ACQ image, as recommended for this star with V magnitude of 18.8. It also ensures the brightness is weighted most strongly toward red wavelengths, where the target star is brightest. We estimated the exposure time for several stellar models close to the target star (STIS.ta.781640, STIS.ta.781641, STIS.ta.781643). Exposure times to reach a SNR of 40 range from 1.5 to 3.6s, and minimum saturation time is 290s. We thus choose an exposure time of 5s. We used Aladin to check that the closest star is at a distance of more than 220 arcsec. There is thus no chance that STIS acquires another object in the 5x5 arcsec search area. The ETC lists a time to saturation through the 52X0.05 slit of 1086s (for a black body model with the same temperature as the star). With our 10s exposure, we should reach 5600 source electrons, above the 5000 required for peak-up with the mirror element. The target star is a M8 ultracool dwarf from which we expect a much lower emission at Lyman-alpha than from GJ436 targeted in program GO#12965 (in the GJ140M spectral range, the stellar emission from these stars will arise from the Lyman-alpha line alone). We can thus use safely the same settings as program GO#12965. 1477638844259 The scheduling data was generated by CASM 24.2. CASM was run in Phase II mode. /private/var/folders/33/rs56p2wx5q174bfyvvm_nq1m0000gn/T/OPVisit657209011222455995.xml This visit targets the transit of planet TRAPPIST 1c, and we indicate relevant lower/upper phase constraints in the ACQ subexposure. Furthermore, the visit should be obtained at a time when planet TRAPPIST-1b is far after its own transit, so as not to contaminate the observation of planet 'c' transit. We thus indicate in the timing requirements the windows when planet 'c' transits and planet 'b' is between orbital phases 0.5 to 0.85. Finally, we also request that visit 3 be scheduled at least 15 days after visit 1. The first opportunity for visit 1 being on 16 June 2017, we thus provide all possible opportunities for visit 3 starting at least 15 days after this date, and until the end of November 2016. (Tic-Visit :proposal-id 14493 :visit-id "03" :proposal-version -1 :trans-version "20160601" :date "28-Oct-2016 09:14:04.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 226608 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14493 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14493 :visit-id "03" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2880 :al-overhead-at-end 0 :internal-dur-at-end 639 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3213 :pcs-gap 0 ) true 1 0 We use the F28X50LP filter for this ACQ image, as recommended for this star with V magnitude of 18.8. It also ensures the brightness is weighted most strongly toward red wavelengths, where the target star is brightest. We estimated the exposure time for several stellar models close to the target star (STIS.ta.781640, STIS.ta.781641, STIS.ta.781643). Exposure times to reach a SNR of 40 range from 1.5 to 3.6s, and minimum saturation time is 290s. We thus choose an exposure time of 5s. We used Aladin to check that the closest star is at a distance of more than 220 arcsec. There is thus no chance that STIS acquires another object in the 5x5 arcsec search area. The ETC lists a time to saturation through the 52X0.05 slit of 1086s (for a black body model with the same temperature as the star). With our 10s exposure, we should reach 5600 source electrons, above the 5000 required for peak-up with the mirror element. The target star is a M8 ultracool dwarf from which we expect a much lower emission at Lyman-alpha than from GJ436 targeted in program GO#12965 (in the GJ140M spectral range, the stellar emission from these stars will arise from the Lyman-alpha line alone). We can thus use safely the same settings as program GO#12965.