14877( 3) - 20-Dec-2016 00:27:47 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 14877 Version: 3 Check-in Time: 20-Dec-2016 00:27:47 STScI Edit Number: 0 Title Confirmation and characterization of an exosphere around the super Earth 55 Cnc e ------------------------------------------------------------------------------------ Type Cycle GO 24 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Vincent Bourrier Observatoire de Geneve Y CoI: Dr. David Ehrenreich Observatoire de Geneve N CoI: Dr. Alain Lecavelier des Etangs CNRS, Institut d'Astrophysique de Paris N CoI: Dr. Francesco Pepe Observatoire de Geneve N CoI: Mr. Baptiste Lavie University of Bern N ------------------------------------------------------------------------------------ Abstract The super-Earth 55 Cnc e transits an extremely bright star (V=6) at a very short separation (a=0.016 au). Transit spectroscopy of the planet in the ultraviolet detected no significant amounts of hydrogen or water, while optical and infrared observations suggest it could either have no atmosphere, or be surrounded by a heavyweight metal-rich envelope. Located within a carbon-rich system, 55 Cnc e might indeed be a 'Super-Venus' with a carbon-dioxyde atmosphere that could expand under the strong stellar irradiation. Our recent observation of the transit at far UV wavelengths with HST/COS may bring a new and decisive insight in favor of this scenario. Indeed, we detect a significant absorption signature of ionized carbon during and after the optical transit of 55 Cnc e. However, while this could represent the first clear detection of an exosphere around a super Earth, it relies on a single visit and previous experience demonstrates the importance of repeatability. Furthermore, a single visit is not enough to fully interpret the dynamics of the putative carbon exosphere. With two independent visits of five orbits each, a Mid-Cycle program is the perfect opportunity to assess the repeatability of this absorption, and characterize an envelope of carbon around 55 Cnc e. For the foreseeable future, the Hubble Space Telescope provides our only option to observe the transit of this super Earth at UV wavelengths, and indeed represents a unique possibility to characterize the atmosphere of this small planet, its composition, and its evolution. ------------------------------------------------------------------------------------ Observations Description ------------------------ This program consists in 2 visits of 5 HST orbits each (total of 10 HST orbits), dedicated to the observations of the transits of the exoplanet 55 Cancri e in front of their host-star. The aim is to confirm a signature detected in the frame of Visit 2 in GO#14094, and this program will thus use the same instrumental settings. The scheduling will be slightly different however, because this new program has one more orbit per visit, and we need to obtain a good baseline by measuring the stellar flux farther from the planet transit. The transits of the targeted planet 55 Cancri 'e' occur every 17.7 hours and last for about 1.5 hours. The timing requirements for both visits are set as 14877( 3) - 20-Dec-2016 00:27:47 - [ 2] phase constraints on the first ACQ exposure of the first orbit. ------------------------------------------------------------------------------------ 14877( 3) - 20-Dec-2016 00:27:47 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 -RHO-CNC STAR, EXTRA-SOLAR RA=08H52M35.8109S +/- 0.0085", J2000 V = V = 5.95 U=7.45, B=6.82, R=5.4, I=5.0, PLANETARY SYSTEM, G DEC=+28D19'50.95" +/- 0.006" 27.36 J=4.59, H=4.14, K=4.015 V-IV Reference Frame: ICRS Extended: NO Comments: This star is in a double system (common proper motions) with 55 Cancri B (GJ 324B), a much fainter (V=13) M4 dwarf that is 1.4-arcmin away. It also 4.6-arcmin away from the similarly bright (V=6.3) star 53 Cancri (BO Cancri) Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000 -0.03679373930991556 -0.23405 0.08103 ------------------------------------------------------------------------------------------------------------------------------------ 14877( 3) - 20-Dec-2016 00:27:47 - [ 4] Visit: 01 Visit Requirements: SCHED 100%; Period 0.736543 D AND ZERO-PHASE HJD2455733.008 On Hold Comments: Additional Comments: 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 -RHO-CNC COS/NUV ACQ/IMA BOA MIRRORA 1 80 S (80 PHASE 0.737 TO 0.754; GE S) SEQ 1-2 NON-INT Comments: We compared the counts for the brightest pixel in the acquisition image of GO#14094, and the value predicted for similar settings with the ETC but the GALEX magnitude (12.93 in NUV band). There is a ratio of about 7.5 between the actual count (lower) and the predicted count. Then, we used the ETC with the GALEX magnitude and mirror A to find that an exposure time of 80s is required to obtain a predicted count of 3230 for the brightest pixel, which should correspond to a true count of 430 and a SNR of 55 (assuming the ratio of 7.5 between the predicted and true counts) ------------------------------------------------------------------------------------------------------------------------------------ 2 -RHO-CNC COS/FUV TIME-TA PSA G130M 1291 FLASH=YES, FP-POS=ALL, 1 535 S G BUFFER-TIME=1000 see below (1772 S) Comments: In the ETC run, the strength of the stellar Lyman-alpha line has been set to an extremely conservative value, and the airglow as set to its higher value, in order to calculate the buffer-time. We use the same settings as in Visit 2 of GO#14094, which was successfully obtained. ------------------------------------------------------------------------------------------------------------------------------------ 3 -RHO-CNC COS/FUV TIME-TA PSA G130M 1291 FLASH=YES, FP-POS=ALL, 1 535 S SEQ 3 NON-INT G BUFFER-TIME=1000 see below (2248 S) Comments: In the ETC run, the strength of the stellar Lyman-alpha line has been set to an extremely conservative value, and the airglow as set to its higher value, in order to calculate the buffer-time. ------------------------------------------------------------------------------------------------------------------------------------ 14877( 3) - 20-Dec-2016 00:27:47 - [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 4 -RHO-CNC COS/FUV TIME-TA PSA G130M 1291 FLASH=YES, FP-POS=ALL, 1 535 S SEQ 4 NON-INT G BUFFER-TIME=1000 see below (2248 S) Comments: In the ETC run, the strength of the stellar Lyman-alpha line has been set to an extremely conservative value, and the airglow as set to its higher value, in order to calculate the buffer-time. ------------------------------------------------------------------------------------------------------------------------------------ 5 -RHO-CNC COS/FUV TIME-TA PSA G130M 1291 FLASH=YES, FP-POS=ALL, 1 535 S SEQ 5 NON-INT G BUFFER-TIME=1000 see below (2248 S) Comments: In the ETC run, the strength of the stellar Lyman-alpha line has been set to an extremely conservative value, and the airglow as set to its higher value, in order to calculate the buffer-time. ------------------------------------------------------------------------------------------------------------------------------------ 6 -RHO-CNC COS/FUV TIME-TA PSA G130M 1291 FLASH=YES, FP-POS=ALL, 1 535 S SEQ 6 NON-INT G BUFFER-TIME=1000 see below (2248 S) Comments: In the ETC run, the strength of the stellar Lyman-alpha line has been set to an extremely conservative value, and the airglow as set to its higher value, in order to calculate the buffer-time. ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ -RHO-CNC 1 COS/NUV ACQ/IMA BOA MIRRORA none none none none 1 N/A GE -RHO-CNC 2 COS/FUV TIME-TA PSA G130M 1291 none none none 1 1 443.0 S G -RHO-CNC 2 COS/FUV TIME-TA PSA G130M 1291 none none none 2 1 443.0 S G -RHO-CNC 2 COS/FUV TIME-TA PSA G130M 1291 none none none 3 1 443.0 S G -RHO-CNC 2 COS/FUV TIME-TA PSA G130M 1291 none none none 4 1 443.0 S G -RHO-CNC 3 COS/FUV TIME-TA PSA G130M 1291 none none none 1 2 562.0 S G -RHO-CNC 3 COS/FUV TIME-TA PSA G130M 1291 none none none 2 2 562.0 S G 14877( 3) - 20-Dec-2016 00:27:47 - [ 6] 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 | ------------------------------------------------------------------------------------------------------------------------------------ -RHO-CNC 3 COS/FUV TIME-TA PSA G130M 1291 none none none 3 2 562.0 S G -RHO-CNC 3 COS/FUV TIME-TA PSA G130M 1291 none none none 4 2 562.0 S G -RHO-CNC 4 COS/FUV TIME-TA PSA G130M 1291 none none none 1 3 562.0 S G -RHO-CNC 4 COS/FUV TIME-TA PSA G130M 1291 none none none 2 3 562.0 S G -RHO-CNC 4 COS/FUV TIME-TA PSA G130M 1291 none none none 3 3 562.0 S G -RHO-CNC 4 COS/FUV TIME-TA PSA G130M 1291 none none none 4 3 562.0 S G -RHO-CNC 5 COS/FUV TIME-TA PSA G130M 1291 none none none 1 4 562.0 S G -RHO-CNC 5 COS/FUV TIME-TA PSA G130M 1291 none none none 2 4 562.0 S G -RHO-CNC 5 COS/FUV TIME-TA PSA G130M 1291 none none none 3 4 562.0 S G -RHO-CNC 5 COS/FUV TIME-TA PSA G130M 1291 none none none 4 4 562.0 S G -RHO-CNC 6 COS/FUV TIME-TA PSA G130M 1291 none none none 1 5 562.0 S G -RHO-CNC 6 COS/FUV TIME-TA PSA G130M 1291 none none none 2 5 562.0 S G -RHO-CNC 6 COS/FUV TIME-TA PSA G130M 1291 none none none 3 5 562.0 S G -RHO-CNC 6 COS/FUV TIME-TA PSA G130M 1291 none none none 4 5 562.0 S G 14877( 3) - 20-Dec-2016 00:27:47 - [ 7] Visit: 02 Visit Requirements: SCHED 100%; Period 0.736543 D AND ZERO-PHASE HJD2455733.008 On Hold Comments: Additional Comments: 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 -RHO-CNC COS/NUV ACQ/IMA BOA MIRRORA 1 80 S (80 PHASE 0.779 TO 0.815; GE S) SEQ 1-2 NON-INT Comments: See visit #01 ------------------------------------------------------------------------------------------------------------------------------------ 2 -RHO-CNC COS/FUV TIME-TA PSA G130M 1291 FLASH=YES, FP-POS=ALL, 1 535 S G BUFFER-TIME=1000 see below (1772 S) Comments: In the ETC run, the strength of the stellar Lyman-alpha line has been set to an extremely conservative value, and the airglow as set to its higher value, in order to calculate the buffer-time. We use the same settings as in Visit 2 of GO#14094, which was successfully obtained. ------------------------------------------------------------------------------------------------------------------------------------ 3 -RHO-CNC COS/FUV TIME-TA PSA G130M 1291 FLASH=YES, FP-POS=ALL, 1 535 S SEQ 3 NON-INT G BUFFER-TIME=1000 see below (2248 S) Comments: In the ETC run, the strength of the stellar Lyman-alpha line has been set to an extremely conservative value, and the airglow as set to its higher value, in order to calculate the buffer-time. ------------------------------------------------------------------------------------------------------------------------------------ 4 -RHO-CNC COS/FUV TIME-TA PSA G130M 1291 FLASH=YES, FP-POS=ALL, 1 535 S SEQ 4 NON-INT G BUFFER-TIME=1000 see below (2248 S) Comments: In the ETC run, the strength of the stellar Lyman-alpha line has been set to an extremely conservative value, and the airglow as set to its higher value, in order to calculate the buffer-time. ------------------------------------------------------------------------------------------------------------------------------------ 5 -RHO-CNC COS/FUV TIME-TA PSA G130M 1291 FLASH=YES, FP-POS=ALL, 1 535 S SEQ 5 NON-INT G BUFFER-TIME=1000 see below (2248 S) Comments: In the ETC run, the strength of the stellar Lyman-alpha line has been set to an extremely conservative value, and the airglow as set to its higher value, in order to calculate the buffer-time. ------------------------------------------------------------------------------------------------------------------------------------ 14877( 3) - 20-Dec-2016 00:27:47 - [ 8] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 6 -RHO-CNC COS/FUV TIME-TA PSA G130M 1291 FLASH=YES, FP-POS=ALL, 1 535 S SEQ 6 NON-INT G BUFFER-TIME=1000 see below (2248 S) Comments: In the ETC run, the strength of the stellar Lyman-alpha line has been set to an extremely conservative value, and the airglow as set to its higher value, in order to calculate the buffer-time. ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ -RHO-CNC 1 COS/NUV ACQ/IMA BOA MIRRORA none none none none 1 N/A GE -RHO-CNC 2 COS/FUV TIME-TA PSA G130M 1291 none none none 1 1 443.0 S G -RHO-CNC 2 COS/FUV TIME-TA PSA G130M 1291 none none none 2 1 443.0 S G -RHO-CNC 2 COS/FUV TIME-TA PSA G130M 1291 none none none 3 1 443.0 S G -RHO-CNC 2 COS/FUV TIME-TA PSA G130M 1291 none none none 4 1 443.0 S G -RHO-CNC 3 COS/FUV TIME-TA PSA G130M 1291 none none none 1 2 562.0 S G -RHO-CNC 3 COS/FUV TIME-TA PSA G130M 1291 none none none 2 2 562.0 S G -RHO-CNC 3 COS/FUV TIME-TA PSA G130M 1291 none none none 3 2 562.0 S G -RHO-CNC 3 COS/FUV TIME-TA PSA G130M 1291 none none none 4 2 562.0 S G -RHO-CNC 4 COS/FUV TIME-TA PSA G130M 1291 none none none 1 3 562.0 S G -RHO-CNC 4 COS/FUV TIME-TA PSA G130M 1291 none none none 2 3 562.0 S G -RHO-CNC 4 COS/FUV TIME-TA PSA G130M 1291 none none none 3 3 562.0 S G -RHO-CNC 4 COS/FUV TIME-TA PSA G130M 1291 none none none 4 3 562.0 S G -RHO-CNC 5 COS/FUV TIME-TA PSA G130M 1291 none none none 1 4 562.0 S G -RHO-CNC 5 COS/FUV TIME-TA PSA G130M 1291 none none none 2 4 562.0 S G -RHO-CNC 5 COS/FUV TIME-TA PSA G130M 1291 none none none 3 4 562.0 S G 14877( 3) - 20-Dec-2016 00:27:47 - [ 9] 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 | ------------------------------------------------------------------------------------------------------------------------------------ -RHO-CNC 5 COS/FUV TIME-TA PSA G130M 1291 none none none 4 4 562.0 S G -RHO-CNC 6 COS/FUV TIME-TA PSA G130M 1291 none none none 1 5 562.0 S G -RHO-CNC 6 COS/FUV TIME-TA PSA G130M 1291 none none none 2 5 562.0 S G -RHO-CNC 6 COS/FUV TIME-TA PSA G130M 1291 none none none 3 5 562.0 S G -RHO-CNC 6 COS/FUV TIME-TA PSA G130M 1291 none none none 4 5 562.0 S G 14877( 3) - 20-Dec-2016 00:27:47 - [ 10] Summary Form for Proposal 14877 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures BOA, PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV, COS/NUV ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/IMAGE, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=1000, FLASH=YES, FP-POS=ALL ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PHASE 0.737 TO 0.754, PHASE 0.779 TO 0.815, Period 0.736543 D AND ZERO-PHASE HJD2455733.008 , SCHED 100%, SEQ 1-2 NON-INT, SEQ 3 NON-INT, SEQ 4 NON-INT, SEQ 5 NON-INT, SEQ 6 NON-INT ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G130M, MIRRORA ------------------------------------------------------------------------------------------------------------------------------------ Target Names -RHO-CNC ------------------------------------------------------------------------------------------------------------------------------------