Confirming a Sub-Earth-Sized Exoplanet in the Solar Neighborhood

Updated ephemeris for Visit 2 (11,12,13,14). No longer on hold, ready to shoot in Jan/Feb 2014. -1745734394 ----- Attempting Submission 6 (Thu Dec 19 21:16:26 GMT 2013) ----- ----- Attempting Submission 7 (Tue Dec 31 22:32:48 GMT 2013) ----- All tools were run for uncompleted visits. Confirming a Sub-Earth-Sized Exoplanet in the Solar Neighborhood The future of exoplanet characterization is moving towards atmospheric studies of transiting rocky exoplanets. The paucity of nearby candidates suitable for these studies is a pressing issue in the exoplanet community and several current and proposed programs (such as MEarth and TESS) are working towards uncovering these Earth-sized planets. We recently published evidence for at least one new exoplanet candidate in the GJ 436 system. If confirmed, UCF-1.01 would be one of the smallest exoplanets currently detected and, at a distance of only 10.2 pc, it would be the most easily-observable transiting rocky planet outside of the Solar System and part of the first compact system of planets orbiting a nearby M dwarf. The GJ 436 system would become a prime target for follow-up investigations in fields such as interiors, atmospheres, dynamics, and further radial-velocity and transit searches. In order to secure a firm detection, we require the stability and photon-gathering power of the Hubble Space Telescope. With only eight orbits around the Earth, HST is capable of confirming the presence of UCF-1.01 with an unassailable significance of 20 sigma. HST's two visits would obtain good phase coverage of the entire 45-minute transit, confirm consistency in the measured transit depths, and place better constraints on the planet's physical and orbital parameters. No other facility is currently capable of validating this exoplanet candidate and growing uncertainty in the mid-transit time is adding a real urgency to this task. Cycle 21 is now our best opportunity to definitively confirm the existence of the first sub-Earth-sized exoplanet in the solar neighborhood. This project aims to confirm the existence of a sub-Earth-sized exoplanet in the GJ 436 system. We will use WFC3 in spatial scan mode to observe the bright M-dwarf GJ 436 during predicted transit times. Each transit visit consists of 4 linked Visits (1 Visit per orbit) to ensure WFC3 performs a buffer dump at the end of each orbit. Otherwise, dumps would occur mid-observation. Orbits are timed such that two happen before the transit, one happens during transit, and one happens after the transit. There will be two visits to the target. Each orbit follows the same sequence: a direct image is obtained through the F126N filter for wavelength calibration, and then the rest of the orbit is filled with a series of exposures with the G141 grism. All observations will be performed with the GRISM256 subarray to save buffer memory and reduce systematics associated with the larger array sizes. The spectroscopic exposures will be obtained with the spatial scan mode. The scan rate will be 1.00 arcsec / sec using FGS guiding and the scan will be in the spatial direction to smear out the spectrum so that reasonable counts per pixel are maintained during a long exposure to reduce systematics from non-linearity and persistence. We are aiming for less than 40,000 electrons per pixel per exposure. The observations must be conducted such that the third orbit is in transit. The transits occur every 1.3659 days, and last for 45 minutes. We have set the phase constraints corresponding to this requirement. We use 'Betweens' to avoid observations near transit/eclipse events of GJ 436b. EXTRA-SOLAR PLANETS 12 false false 0.0 0.0 false false false SUPPORTED STAR M V-IV This object was generated by the targetselector and retrieved from the SIMBAD database. LHS-310 J2000 J2000 H = 6.3 WFC3/IR Spectroscopic No No G141 Timing link suitability includes constraints ([Sequence (01 02 03 04) within 0.3 days]) Hst Same orient constraint links visits (01 02 03 04 12 13 14) The scheduling data was generated by CASM 21.2. CASM was run in Phase II mode. 1387486953934 Due to increasing uncertainty in the planet's transit times, the program's science goals of detecting a sub-Earth-sized exoplanet will best be achieved by scheduling Visit 1 as soon as possible (Nov 24 - Dec 8). Waiting until May 2014 increases the risk of missing a significant fraction of the transit event, thus decreasing the significance of the detection. Orientation constraints are necessary to avoid overlapping spectra from a nearby stellar object (Hmag = 15.9, RA = 11:42:11.64, Dec = 26:42:49.6). We use 'Betweens' to avoid observations near transit/eclipse events of GJ 436b. Each transit visit consists of 4 linked Visits (1 Visit per orbit) to ensure WFC3 performs a buffer dump at the end of each orbit. Otherwise, dumps would occur mid-observation. Numerical simulations predict that the planet will exhibit ~10-minute transit timing variations (TTVs) with a period of ~40 days. The relatively short observing windows will help to measure transits near maximum TTV variation. We are using the average orbital period from the TTV simulations, instead of the published value. 1387289032000 291.0 (Tic-Visit :proposal-id 13338 :visit-id "01" :proposal-version -1 :trans-version "20130502" :date "19-Dec-2013 16:02:31.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 214816 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13338 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13338 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2761 :al-overhead-at-end 0 :internal-dur-at-end 316 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3253 :pcs-gap 0 ) false 1 0 Timing link suitability includes constraints ([Sequence (01 02 03 04) within 0.3 days]) Hst Same orient constraint links visits (01 02 03 04 12 13 14) The scheduling data was generated by CASM 21.2. CASM was run in Phase II mode. 1387294770000 291.0 (Tic-Visit :proposal-id 13338 :visit-id "02" :proposal-version -1 :trans-version "20130502" :date "21-Nov-2013 12:09:54.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 214816 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13338 :visit-id "02" :obset-id "02" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13338 :visit-id "02" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2761 :al-overhead-at-end 0 :internal-dur-at-end 316 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3253 :pcs-gap 0 ) true 1 0 Timing link suitability includes constraints ([Sequence (01 02 03 04) within 0.3 days]) Hst Same orient constraint links visits (01 02 03 04 12 13 14) The scheduling data was generated by CASM 21.2. CASM was run in Phase II mode. 1387300508000 291.0 (Tic-Visit :proposal-id 13338 :visit-id "03" :proposal-version -1 :trans-version "20130502" :date "21-Nov-2013 12:10:07.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 214816 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13338 :visit-id "03" :obset-id "03" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13338 :visit-id "03" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2761 :al-overhead-at-end 0 :internal-dur-at-end 316 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3253 :pcs-gap 0 ) true 1 0 Timing link suitability includes constraints ([Sequence (01 02 03 04) within 0.3 days]) Hst Same orient constraint links visits (01 02 03 04 12 13 14) The scheduling data was generated by CASM 21.2. CASM was run in Phase II mode. 1387306246000 291.0 (Tic-Visit :proposal-id 13338 :visit-id "04" :proposal-version -1 :trans-version "20130502" :date "21-Nov-2013 12:10:19.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 214816 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13338 :visit-id "04" :obset-id "04" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13338 :visit-id "04" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2761 :al-overhead-at-end 0 :internal-dur-at-end 316 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3253 :pcs-gap 0 ) true 1 0 Timing link suitability includes constraints ([Sequence (11 12 13 14) within 0.3 days]) Hst Same orient constraint links visits (11 12 13 14) The scheduling data was generated by CASM 21.2. CASM was run in Phase II mode. 1388528815585 Orientation constraints are necessary to avoid overlapping spectra from a nearby stellar object (Hmag = 15.9, RA = 11:42:11.64, Dec = 26:42:49.6). We use 'Betweens' to avoid observations near transit/eclipse events of GJ 436b. Each transit visit consists of 4 linked Visits (1 Visit per orbit) to ensure WFC3 performs a buffer dump at the end of each orbit. Otherwise, dumps would occur mid-observation. Numerical simulations predict that the planet will exhibit ~10-minute transit timing variations (TTVs) with a period of ~40 days. The relatively short observing windows will help to measure transits near maximum TTV variation. We are using the average orbital period from the TTV simulations, instead of the published value. (Tic-Visit :proposal-id 13338 :visit-id "11" :proposal-version -1 :trans-version "20130502" :date "31-Dec-2013 17:26:52.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 214816 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13338 :visit-id "11" :obset-id "11" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13338 :visit-id "11" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2761 :al-overhead-at-end 0 :internal-dur-at-end 316 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3106 :pcs-gap 0 ) false 1 0 Timing link suitability includes constraints ([Sequence (11 12 13 14) within 0.3 days]) Hst Same orient constraint links visits (11 12 13 14) The scheduling data was generated by CASM 21.2. CASM was run in Phase II mode. 1388528829845 (Tic-Visit :proposal-id 13338 :visit-id "12" :proposal-version -1 :trans-version "20130502" :date "31-Dec-2013 17:27:07.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 214816 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13338 :visit-id "12" :obset-id "12" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13338 :visit-id "12" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2761 :al-overhead-at-end 0 :internal-dur-at-end 316 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3106 :pcs-gap 0 ) true 1 0 Timing link suitability includes constraints ([Sequence (11 12 13 14) within 0.3 days]) Hst Same orient constraint links visits (11 12 13 14) The scheduling data was generated by CASM 21.2. CASM was run in Phase II mode. 1388528842597 (Tic-Visit :proposal-id 13338 :visit-id "13" :proposal-version -1 :trans-version "20130502" :date "31-Dec-2013 17:27:20.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 214816 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13338 :visit-id "13" :obset-id "13" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13338 :visit-id "13" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2761 :al-overhead-at-end 0 :internal-dur-at-end 316 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3106 :pcs-gap 0 ) true 1 0 Timing link suitability includes constraints ([Sequence (11 12 13 14) within 0.3 days]) Hst Same orient constraint links visits (11 12 13 14) The scheduling data was generated by CASM 21.2. CASM was run in Phase II mode. 1388528854324 (Tic-Visit :proposal-id 13338 :visit-id "14" :proposal-version -1 :trans-version "20130502" :date "31-Dec-2013 17:27:31.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "30" :si-bright-earth-limb-angle 20.0 :data-volume 214816 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13338 :visit-id "14" :obset-id "14" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13338 :visit-id "14" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2761 :al-overhead-at-end 0 :internal-dur-at-end 316 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3106 :pcs-gap 0 ) true 1 0