15859( 4) - 02-Dec-2019 15:23:23 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 15859 Version: 4 Check-in Time: 02-Dec-2019 15:23:23 STScI Edit Number: 0 Title Traveling across the valley: comparative exoplanetology in the GJ 9827 system ------------------------------------------------------------------------------------ Type Cycle GO 27 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Vincent Bourrier Observatoire de Geneve Y CoI: Prof. David Ehrenreich Observatoire de Geneve N CoI: Dr. Baptiste Lavie Observatoire de Geneve N CoI: Mr. Leonardo Dos Santos University of Geneva-Department of N Astronomy CoI: Mr. Romain Allart Observatoire de Geneve N CoI: Dr. Martin Turbet Observatoire de Geneve N CoI: Dr. Alain Lecavelier des Etangs CNRS, Institut d'Astrophysique de Paris N ------------------------------------------------------------------------------------ Abstract The transition between rocky and volatile-rich planets is one of the most topical questions. The valley found to split the population of small close-in planets into 2 size regimes is thought to originate from atmospheric escape: some planets lose their atmosphere while others retain their volatile species. The 3-planets system orbiting GJ9827 spans the breadth of the valley: GJ9827c is on its low-radius side, and likely lost its volatile envelope; GJ9827b may be one of the few planets to have formed without an envelope within the valley, or it could have a water-rich envelope resilient to escape; GJ9827d is on the large-radius side, and the most favorable for atmospheric escape detection. GJ9827 is one of the few multi-planet systems whose star is bright and close enough for Ly-alpha transit spectroscopy. GJ9827b is being observed as part of an ongoing HST/UV program, and we propose to complete the exploration of the system by observing 2 transits of GJ9827d with STIS in the Ly-alpha line (10 HST orbits in total). The planet is sufficiently irradiated to evaporate, but a much larger hydrogen escape is expected from a H/He atmosphere compared to a water-rich envelope, both proposed to explain GJ9827d properties. Detecting a giant hydrogen cloud would thus favor an H/He atmosphere, while a non-detection or low hydrogen escape would favor a water-rich envelope acquired beyond the snowline. The program will constrain the nature of GJ9827d and the origin of the GJ9827 system, improve our understanding of the role played by evaporation in the transition from mini-Neptunes to super-Earths, and inform the community for an in-depth characterization of the GJ9827 planets with JWST ------------------------------------------------------------------------------------ Observations Description ------------------------ This program consists in 2 visits of 5 HST orbits each. In each visit, we will observe the transit of an exoplanet (GJ9827d) in front of its host star. Transits occur every 6.2 days (the orbital period of the planet) and last for 1.2 hours. The goal is to search for a hydrogen exosphere surrounding the planet and occulting the star at Lyman-alpha. The timing requirements are set as phase constraints on the first ACQ exposure of the first orbit in a visit, with allowed start phase range of 25 min. 15859( 4) - 02-Dec-2019 15:23:23 - [ 2] Visits could be reduced to 4 HST orbits each if scheduling proves too difficult, however our science goals would be better reached with 5 orbits. Two orbits before the planet transit are required to measure the flux from the unocculted star, one orbit is scheduled during the nominal planet transit (when absorption from a putative extended exosphere is maximum), and two orbits scheduled after the transit will allow us to search for and characterize an exospheric tail trailing the planet. We set BETWEEN constraints for the two visits to avoid time windows when other planets in the system (GJ9827b and GJ9827c) transit as well. Ideally the two visits should further be scheduled between July 25th 2019 and December 13rd 2019, or between July, 25th 2020 and December, 13rd 2020 to reduce airglow contamination. It would be best for our science goals if the two visits could be scheduled as close as possible to each other, and as closes as possible to the start of these windows. These constraints can however be removed if scheduling proves too difficult. We use the same settings as GO#15434, which used STIS/FUV-MAMA and the G140M grism centered on a wavelength of 1, 222 to observe the transit of GJ9827b at Lyman-alpha. ------------------------------------------------------------------------------------ 15859( 4) - 02-Dec-2019 15:23:23 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 GJ9827 STAR, EXTRA-SOLAR RA=23H27M4.8377S +/- 0.0511", J2000 V = 32.1 V = 10.1 B =11.57 , R =10.09 , I =8.89 PLANET, K V-IV DEC=-01D17'10.59" +/- 0.0358" , G =9.8377 , J =7.984 , H =7.379 , K =7.193 , i = 9.18 Reference Frame: ICRS Extended: NO Comments: All target properties come from the SIMBAD database. We used the confirmation charts to check that the coordinates and proper motion were correct. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 0.025074251660895934 0.21607099999999999 0.0336855 ------------------------------------------------------------------------------------------------------------------------------------ 15859( 4) - 02-Dec-2019 15:23:23 - [ 4] Visit: 01 Visit Requirements: SCHED 100%; Period 6.201467 D AND ZERO-PHASE HJD2457740.96110 On Hold Comments: Additional Comments: We set a BETWEEN constraint to limit airglow contamination Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 GJ9827 STIS/CCD ACQ F25ND3 MIRROR ACQTYPE=POINT 1 6.6 S (6.6 PHASE 0.965 TO 0.9773; S) SEQ 1-4 NON-INT Comments: Same settings as GO#15434 ------------------------------------------------------------------------------------------------------------------------------------ 2 GJ9827 STIS/CCD ACQ/PEA 31X0.05ND G430L 4300 1 1 S (1 S) K C Comments: Same settings as GO#15434 ------------------------------------------------------------------------------------------------------------------------------------ 3 GJ9827 STIS/FUV TIME-TA 52X0.1D1 G140M 1222 BUFFER-TIME=900, WAVECAL=NO 1 1786 S -MAMA G see below (1502 S) Comments: Same settings as GO#15434 ------------------------------------------------------------------------------------------------------------------------------------ 4 WAVE STIS/FUV ACCUM 52X0.1 G140M 1222 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 5 GJ9827 STIS/FUV TIME-TA 52X0.1D1 G140M 1222 BUFFER-TIME=900, WAVECAL=NO 1 2890 S SEQ 5-6 NON-INT -MAMA G see below (2586 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 WAVE STIS/FUV ACCUM 52X0.1 G140M 1222 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 7 GJ9827 STIS/FUV TIME-TA 52X0.1D1 G140M 1222 BUFFER-TIME=900, WAVECAL=NO 1 3000 S SEQ 7-8 NON-INT -MAMA G see below (2586 S) ------------------------------------------------------------------------------------------------------------------------------------ 8 WAVE STIS/FUV ACCUM 52X0.1 G140M 1222 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 9 GJ9827 STIS/FUV TIME-TA 52X0.1D1 G140M 1222 BUFFER-TIME=900, WAVECAL=NO 1 3000 S SEQ 9-10 NON-INT -MAMA G see below (2586 S) ------------------------------------------------------------------------------------------------------------------------------------ 10 WAVE STIS/FUV ACCUM 52X0.1 G140M 1222 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 11 GJ9827 STIS/FUV TIME-TA 52X0.1D1 G140M 1222 BUFFER-TIME=900, WAVECAL=NO 1 3000 S SEQ 11-12 NON-INT -MAMA G see below (2586 S) ------------------------------------------------------------------------------------------------------------------------------------ 15859( 4) - 02-Dec-2019 15:23:23 - [ 5] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 12 WAVE STIS/FUV ACCUM 52X0.1 G140M 1222 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ GJ9827 1 STIS/CCD ACQ F25ND3 MIRROR none none none none 1 N/A GJ9827 2 STIS/CCD ACQ/PEA 31X0.05N G430L 4300 none none none none 1 N/A K DC GJ9827 3 STIS/FUV TIME-TA 52X0.1D1 G140M 1222 none none none none 1 1502.0 S -MAMA G WAVE 4 STIS/FUV ACCUM 52X0.1 G140M 1222 none none none none 1 N/A -MAMA GJ9827 5 STIS/FUV TIME-TA 52X0.1D1 G140M 1222 none none none none 2 2586.0 S -MAMA G WAVE 6 STIS/FUV ACCUM 52X0.1 G140M 1222 none none none none 2 N/A -MAMA GJ9827 7 STIS/FUV TIME-TA 52X0.1D1 G140M 1222 none none none none 3 2586.0 S -MAMA G WAVE 8 STIS/FUV ACCUM 52X0.1 G140M 1222 none none none none 3 N/A -MAMA GJ9827 9 STIS/FUV TIME-TA 52X0.1D1 G140M 1222 none none none none 4 2586.0 S -MAMA G WAVE 10 STIS/FUV ACCUM 52X0.1 G140M 1222 none none none none 4 N/A -MAMA GJ9827 11 STIS/FUV TIME-TA 52X0.1D1 G140M 1222 none none none none 5 2586.0 S -MAMA G WAVE 12 STIS/FUV ACCUM 52X0.1 G140M 1222 none none none none 5 N/A -MAMA 15859( 4) - 02-Dec-2019 15:23:23 - [ 6] Visit: 02 Visit Requirements: SCHED 100%; Period 6.201467 D AND ZERO-PHASE HJD2457740.96110 On Hold Comments: Additional Comments: We set a BETWEEN constraint to limit airglow contamination Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 GJ9827 STIS/CCD ACQ F25ND3 MIRROR ACQTYPE=POINT 1 6.6 S (6.6 PHASE 0.965 TO 0.9773; S) SEQ 1-4 NON-INT Comments: Same settings as GO#15434 ------------------------------------------------------------------------------------------------------------------------------------ 2 GJ9827 STIS/CCD ACQ/PEA 31X0.05ND G430L 4300 1 1 S (1 S) K C Comments: Same settings as GO#15434 ------------------------------------------------------------------------------------------------------------------------------------ 3 GJ9827 STIS/FUV TIME-TA 52X0.1D1 G140M 1222 BUFFER-TIME=900, WAVECAL=NO 1 1786 S -MAMA G see below (1502 S) Comments: Same settings as GO#15434 ------------------------------------------------------------------------------------------------------------------------------------ 4 WAVE STIS/FUV ACCUM 52X0.1 G140M 1222 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 5 GJ9827 STIS/FUV TIME-TA 52X0.1D1 G140M 1222 BUFFER-TIME=900, WAVECAL=NO 1 3000 S SEQ 5-6 NON-INT -MAMA G see below (2586 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 WAVE STIS/FUV ACCUM 52X0.1 G140M 1222 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 7 GJ9827 STIS/FUV TIME-TA 52X0.1D1 G140M 1222 BUFFER-TIME=900, WAVECAL=NO 1 3000 S SEQ 7-8 NON-INT -MAMA G see below (2586 S) ------------------------------------------------------------------------------------------------------------------------------------ 8 WAVE STIS/FUV ACCUM 52X0.1 G140M 1222 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 9 GJ9827 STIS/FUV TIME-TA 52X0.1D1 G140M 1222 BUFFER-TIME=900, WAVECAL=NO 1 3000 S SEQ 9-10 NON-INT -MAMA G see below (2586 S) ------------------------------------------------------------------------------------------------------------------------------------ 10 WAVE STIS/FUV ACCUM 52X0.1 G140M 1222 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ 11 GJ9827 STIS/FUV TIME-TA 52X0.1D1 G140M 1222 BUFFER-TIME=900, WAVECAL=NO 1 3000 S SEQ 11-12 NON-INT -MAMA G see below (2586 S) ------------------------------------------------------------------------------------------------------------------------------------ 15859( 4) - 02-Dec-2019 15:23:23 - [ 7] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 12 WAVE STIS/FUV ACCUM 52X0.1 G140M 1222 1 DEF (0 S) -MAMA ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ GJ9827 1 STIS/CCD ACQ F25ND3 MIRROR none none none none 1 N/A GJ9827 2 STIS/CCD ACQ/PEA 31X0.05N G430L 4300 none none none none 1 N/A K DC GJ9827 3 STIS/FUV TIME-TA 52X0.1D1 G140M 1222 none none none none 1 1502.0 S -MAMA G WAVE 4 STIS/FUV ACCUM 52X0.1 G140M 1222 none none none none 1 N/A -MAMA GJ9827 5 STIS/FUV TIME-TA 52X0.1D1 G140M 1222 none none none none 2 2586.0 S -MAMA G WAVE 6 STIS/FUV ACCUM 52X0.1 G140M 1222 none none none none 2 N/A -MAMA GJ9827 7 STIS/FUV TIME-TA 52X0.1D1 G140M 1222 none none none none 3 2586.0 S -MAMA G WAVE 8 STIS/FUV ACCUM 52X0.1 G140M 1222 none none none none 3 N/A -MAMA GJ9827 9 STIS/FUV TIME-TA 52X0.1D1 G140M 1222 none none none none 4 2586.0 S -MAMA G WAVE 10 STIS/FUV ACCUM 52X0.1 G140M 1222 none none none none 4 N/A -MAMA GJ9827 11 STIS/FUV TIME-TA 52X0.1D1 G140M 1222 none none none none 5 2586.0 S -MAMA G WAVE 12 STIS/FUV ACCUM 52X0.1 G140M 1222 none none none none 5 N/A -MAMA 15859( 4) - 02-Dec-2019 15:23:23 - [ 8] Summary Form for Proposal 15859 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 31X0.05NDC, 52X0.1, 52X0.1D1, F25ND3 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD, STIS/FUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, ACQ, ACQ/PEAK, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT, BUFFER-TIME=900, WAVECAL=NO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PHASE 0.965 TO 0.9773, Period 6.201467 D AND ZERO-PHASE HJD2457740.96110, SCHED 100%, SEQ 1-4 NON-INT, SEQ 11-12 NON-INT, SEQ 5-6 NON-INT, SEQ 7-8 NON-INT, SEQ 9-10 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G140M, G430L, MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names GJ9827, WAVE ------------------------------------------------------------------------------------------------------------------------------------