9064( 2) - 02/16/01 12:54 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 9064 Version: 2 Check-in Date: 16-Feb-2001 12:54:06 1.Proposal Title: HI Detection of an Extra-Solar Planetary Atmosphere ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 10 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Alfred Vidal-Madjar CNRS, Institute d'Astrophysique de Paris CoI: Dr Gilda Ballester University of Arizona N CoI: Dr Lotfi BenJaffel Institut d'Astrophysique de Paris N CoI: Dr Roger Ferlet Institut d'Astrophysique de Paris N CoI: Dr Alain Lecavelier Institut d'Astrophysique de Paris N CoI: Dr Michel Mayor Observatoire de Geneve N ------------------------------------------------------------------------------------ 5. Abstract The extra-solar planet discovered around HD 209458 is the unique one also detected through occultation. During its transit, we will obtain spectra of the HI and DI Lyman-Alpha line at 1215 Angstrom. The extremely extended planetary exosphere is expected to produce an absorption line against the stellar chromospheric Lyman-Alpha emission. Because hydrogen is the most abundant element and its scale height in the exosphere is the largest (H is the lightest element), hydrogen is certainly the best suited species to be detected in an extra-solar planetary atmosphere. From a detection we will better understand the status of such peculiar planetary atmospheres while a non detection should underline possible important missing links in our present views on such subjects. Reference spectra obtained in quadrature position of the planet will give as a by-product the possible detection of extra- solar planetary Lyman-Alpha aurorae. All collected spectra will also allow to evaluate the interstellar D/H ratio on this line of sight. ------------------------------------------------------------------------------------ 9064( 2) - 02/16/01 12:54 - [ 2] Observations Description ------------------------ We propose to observe during the planetary transit in front of the star HD 209458 the Lyman-Alpha line using STIS/G140M and E140M mode. The transit occurs every 3.5 days and lasts about 3 hours. Thus each visit allows to obtain scientific data for about 2 consecutive orbits during the transit. We will perform 3 visits of 3 orbits beginning before the occultation and 1 visit of 2 orbits. The observations of the Lyman-Alpha stellar emission before or after the occultation will be used as reference spectra to check the level of Lyman- Alpha variations. We will thus obtain a total time of about 10000 seconds on the target during the occultation. A spectrum is also to be obtained during 2 orbits when the planet is at the quadrature. This spectrum will serve as an independent reference and will provide the opportunity to possibly detect the signature of an exo-planetary aurora. A total of 13 orbits (11+2) are used to perform the present program. Experience from a lot of observations with STIS shows that G140M gives the best compromise between resolution, noise due to scattered light and sensitivity; a visit with E140H will also allow to test the absorption against other stellar lines. Real Time Justification ----------------------- The observations are Time-critical; they must be obtained at two particular phases of the planet orbit: occultation and quadrature. The list of possible schedules is calculted from the radial velocity and photometric surveys of this famous target (Mayor et al.). The occultation lasts about 3 hours, while the constraints on the quadrature is less stringent (about 17 hours). To obtain a good S/N ratio, we propose to observe several transits. We also propose to schedule the observation close to opposition to minimize the perturbation by the terrestrial Lyman-Alpha airglow. This is specified with the BETWEEN keyword. However, we are aware that it may not be possible to follow this requirement and simultaneously follow the need of an observation at a particular phase of the occultation. This BETWEEN requirement must thus be considered as a preference, not critical for the science. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 9064( 2) - 02/16/01 12:54 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 HD209458 STAR, G V-IV RA=22H 3M 10.75S +/- 0.1", J2000 V = - V = 7.65 DEC=18D 53' 3.7" +/- 0.1" 14.7652 B-V = 0.594 V-I = 0.66 TYPE=G0V Coordinate Source: HIPPARCOS/TYCHO_CATALOGUE Comments: Star of extra-solar planet. Proper motion and flux data from Hipparcos/Tycho Catalogue and SIMBAD. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 1991.25 0.00204 -0.01837 0.02124 9064( 2) - 02/16/01 12:54 - [ 4] Visit: 01 Visit Priority: Visit Requirements: PERIOD 3.524739 D AND ZERO-PHASE JD2451659.936750 BETWEEN 18-Jul-2001 AND 14-Oct-2001 On Hold Comments: Additional Comments: Observation near opposition for Beta angle <50 deg. to minimize the airglow. Orbital elements are from Brown et al. (2001). Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 100 HD209458 STIS/C ACQ F28X50O MIRROR ACQTYPE=POINT 1 2.0 S PHASE 0.955 TO 0.995 CD II Comments: Phase = -3.80 to -0.42 hours before mid-transit. Expected CCD peak counts 26500 e-, S/N=205, Global=4.1e3 e-. ------------------------------------------------------------------------------------------------------------------------------------ 101 HD209458 STIS/C ACQ/PEA 52X0.05 G430L 4300 1 2.0 S CD K Comments: Expected CCD peak counts at 3550 e-, S/N=95, Global=5.8e6 e-. ------------------------------------------------------------------------------------------------------------------------------------ 102 HD209458 STIS/F TIME-TA 52X0.1 G140M 1222 BUFFER-TIME=8000 1 1780 S UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 131 HD209458 STIS/C ACQ/PEA 52X0.05 G430L 4300 1 2.0 S CD K ------------------------------------------------------------------------------------------------------------------------------------ 132 HD209458 STIS/F TIME-TA 52X0.1 G140M 1222 BUFFER-TIME=8000 1 2100 S UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 141 HD209458 STIS/C ACQ/PEA 52X0.05 G430L 4300 1 2.0 S CD K ------------------------------------------------------------------------------------------------------------------------------------ 142 HD209458 STIS/F TIME-TA 52X0.1 G140M 1222 BUFFER-TIME=8000 1 2100 S UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 9064( 2) - 02/16/01 12:54 - [ 5] Visit: 02 Visit Priority: Visit Requirements: PERIOD 3.524739 D AND ZERO-PHASE JD2451659.936750 BETWEEN 01-Jul-2001 AND 01-Nov-2001 On Hold Comments: Additional Comments: +/- 2. months from opposition: Beta <60 deg. to minimize airglow. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 100 HD209458 STIS/C ACQ F28X50O MIRROR ACQTYPE=POINT 1 2.0 S PHASE 0.955 TO 0.995 CD II Comments: Phase = -3.80 to -0.42 hours before mid-transit. ------------------------------------------------------------------------------------------------------------------------------------ 101 HD209458 STIS/C ACQ/PEA 52X0.05 G430L 4300 1 2.0 S CD K ------------------------------------------------------------------------------------------------------------------------------------ 102 HD209458 STIS/F TIME-TA 52X0.1 G140M 1222 BUFFER-TIME=8000 1 1780 S UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 131 HD209458 STIS/C ACQ/PEA 52X0.05 G430L 4300 1 2.0 S CD K ------------------------------------------------------------------------------------------------------------------------------------ 132 HD209458 STIS/F TIME-TA 52X0.1 G140M 1222 BUFFER-TIME=8000 1 2100 S UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 141 HD209458 STIS/C ACQ/PEA 52X0.05 G430L 4300 1 2.0 S CD K ------------------------------------------------------------------------------------------------------------------------------------ 142 HD209458 STIS/F TIME-TA 52X0.1 G140M 1222 BUFFER-TIME=8000 1 2100 S UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 9064( 2) - 02/16/01 12:54 - [ 6] Visit: 03 Visit Priority: Visit Requirements: PERIOD 3.524739 D AND ZERO-PHASE JD2451659.936750 BETWEEN 01-Jun-2001 AND 01-Dec-2001 On Hold Comments: Additional Comments: +/- 3 months from opposition: Beta <90 deg. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 100 HD209458 STIS/C ACQ F28X50O MIRROR ACQTYPE=POINT 1 2.0 S PHASE 0.955 TO 0.995 CD II Comments: Phase = -3.80 to -0.42 hours before mid-transit. ------------------------------------------------------------------------------------------------------------------------------------ 101 HD209458 STIS/C ACQ/PEA 52X0.05 G430L 4300 1 2.0 S CD K ------------------------------------------------------------------------------------------------------------------------------------ 102 HD209458 STIS/F TIME-TA 52X0.1 G140M 1222 BUFFER-TIME=8000 1 1780 S UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 131 HD209458 STIS/C ACQ/PEA 52X0.05 G430L 4300 1 2.0 S CD K ------------------------------------------------------------------------------------------------------------------------------------ 132 HD209458 STIS/F TIME-TA 52X0.1 G140M 1222 BUFFER-TIME=8000 1 2100 S UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 141 HD209458 STIS/C ACQ/PEA 52X0.05 G430L 4300 1 2.0 S CD K ------------------------------------------------------------------------------------------------------------------------------------ 142 HD209458 STIS/F TIME-TA 52X0.1 G140M 1222 BUFFER-TIME=8000 1 2100 S UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 9064( 2) - 02/16/01 12:54 - [ 7] Visit: 04 Visit Priority: Visit Requirements: PERIOD 3.524739 D AND ZERO-PHASE JD2451659.936750 BETWEEN 01-Jul-2001 AND 01-Nov-2001 On Hold Comments: Additional Comments: +/- 2. months from opposition: Beta <60 deg. to minimize airglow. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 100 HD209458 STIS/C ACQ F28X50O MIRROR ACQTYPE=POINT 1 2.0 S PHASE 0.967 TO 0.973 CD II Comments: or PHASE 0.998 TO 1.005. Phase = (-2.8 to -2.3) or (-0.17 to 0.42) hours from central time of transit ------------------------------------------------------------------------------------------------------------------------------------ 101 HD209458 STIS/C ACQ/PEA 0.2X0.0 G430L 4300 1 2.0 S CD K 6 Comments: Expected CCD peak counts at 7000 e-, S/N ~ 100 ------------------------------------------------------------------------------------------------------------------------------------ 102 HD209458 STIS/F TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=8000 1 1750 S UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 131 HD209458 STIS/C ACQ/PEA 0.2X0.0 G430L 4300 1 2.0 S CD K 6 ------------------------------------------------------------------------------------------------------------------------------------ 132 HD209458 STIS/F TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=8000 1 2050 S UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 9064( 2) - 02/16/01 12:54 - [ 8] Visit: 05 Visit Priority: Visit Requirements: PERIOD 3.524739 D AND ZERO-PHASE JD2451659.936750 BETWEEN 01-Jul-2001 AND 01-Nov-2001 On Hold Comments: Additional Comments: +/- 2. months from opposition: Beta <60 deg. to minimize airglow. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 100 HD209458 STIS/C ACQ F28X50O MIRROR ACQTYPE=POINT 1 2.0 S PHASE 0.14 TO 0.34 CD II Comments: Planet at quadrature around phase 0.25 ------------------------------------------------------------------------------------------------------------------------------------ 101 HD209458 STIS/C ACQ/PEA 0.2X0.0 G430L 4300 1 2.0 S CD K 6 ------------------------------------------------------------------------------------------------------------------------------------ 102 HD209458 STIS/F TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=8000 1 1750 S UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 131 HD209458 STIS/C ACQ/PEA 0.2X0.0 G430L 4300 1 2.0 S CD K 6 ------------------------------------------------------------------------------------------------------------------------------------ 132 HD209458 STIS/F TIME-TA 0.2X0.2 E140M 1425 BUFFER-TIME=8000 1 2050 S UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 9064( 2) - 02/16/01 12:54 - [ 9] Summary Form for Proposal 9064 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F28X50OII 52X0.05 52X0.1 0.2X0.06 0.2X0.2 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD STIS/FUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACQ/PEAK TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT BUFFER-TIME=8000 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PERIOD 3.524739 D AND ZERO-PHASE JD2451659.936750 BETWEEN 18-Jul-2001 AND 14-Oct-2001 PHASE 0.955 TO 0.995 PERIOD 3.524739 D AND ZERO-PHASE JD2451659.936750 BETWEEN 01-Jul-2001 AND 01-Nov-2001 PERIOD 3.524739 D AND ZERO-PHASE JD2451659.936750 BETWEEN 01-Jun-2001 AND 01-Dec-2001 PHASE 0.967 TO 0.973 PHASE 0.14 TO 0.34 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G430L G140M E140M ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD209458 ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 4300 1222 1425 ------------------------------------------------------------------------------------------------------------------------------------