10441( 3) - 11/02/04 13:59 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 10441 Version: 3 Check-in Date: 02-Nov-2004 18:57:35 1.Proposal Title: Characterizing a Newly-Found Extrasolar Planet ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle 4. Parallel Pointing Tolerance GO/DD 13 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Dr. Timothy M. Brown University Corporation For Atmospheric Research CoI: Dr. Ronald L. Gilliland Space Telescope Science Institute Y CoI: Dr. David W. Latham Smithsonian Institution Astrophysical N Observatory CoI: Dr. David Charbonneau Harvard University N CoI: Dr. Edward W. Dunham Lowell Observatory N CoI: Dr. Georgi Mandushev Lowell Observatory N CoI: Mr. Roi Alonso Instituto de Astrofisica de Canarias N CoI: Mr. Alessandro Sozzetti University of Pittsburgh N CoI: Mr. Francis T. O'Donovan California Institute of Technology N CoI: Dr. Juan A. Belmont Instituto de Astrofisica de Canarias N CoI: Dr. Hans-Joerg Deeg Instituto de Astrofisica de Canarias N ------------------------------------------------------------------------------------ 6. Abstract We propose to observe transits of the newly-discovered extrasolar planet TRES-1 using (1) ACS/HRC to obtain precise time-series photometry of the transit, and (2) NICMOS to measure the strength of water vapor absorption in the planetary atmosphere. The visible light curve will permit an accurate estimate of the planet's diameter by resolving uncertainty concerning the diameter of the parent star, and the water vapor observation can be used to test models of the structure, clouds and composition in the planet's upper atmosphere. ------------------------------------------------------------------------------------ 10441( 3) - 11/02/04 13:59 - [ 2] Observations Description ------------------------ We will observe TRES-1 during three visits on each of ACS/HRC using the grism G800L. Observations will be obtained at extremely high S/N in a time-series mode with a cadence of 2.1 minutes on ACS. The first two orbits of each visit will be phased to preceed a transit of TrES-1, orbits 3 and 4 will be in transit, and the 5th and final orbit will provide out-of-transit normalization in combination with orbit 2. (We have found conditions in the first orbit are unstable and it is best not to include it in the analysis. The science goals for the ACS observations closely parallel the prime goal of the "original" HST program on HD 209458, the GO/DD 8789 to provide a much cleaner transit light curve than possible from the ground, in order to firm up system parameters. For this prime goal 8789 used STIS with the G750M grating in place as a "light bucket", by dispersing the light over many pixels it was possible to count over $10^8$ e- per exposure, and thus reach time-series S/N of 10, 000. Given the $V$ = 7.64 magnitude of HD 209458, even the 570 \AA range of G750M at low- intrinsic efficiency provided 1.55 $\times \, 10^8$ e- per 60 s integration. Using the ACS/HRC grism to disperse the light over about 200 pixels allows collection of 5 $\times 10^7$ e- per exposure while staying 30\% under saturation. Given the much higher efficiency of the G800L on ACS than the medium resolution STIS grating, and that TrES-1 is 4.15 ($V$) magnitudes fainter than HD 209458 it makes perfect sense to switch from STIS to ACS (independent of the STIS loss). Although fainter by $\times$40 in the relevant bandpass, the count rate with HRC/G800L is only $\times$4.9 lower than our original STIS observations. Adopting an exposure time of 95 s, using the 512 square subarray nearest the readout Amp for HRC provides an overhead of 35 s per read, and still encompasses the full zeroth, first and second orders from G800L. With a 130s cycle time it is possible to maintain 73\% observing efficiency on TrES-1, which compares quite favorably to the 75\% we had with HD 209458. The S/N per HST orbit provided by ACS/HRC will be a factor of $\times$2.2 times lower than that realized for the much brighter HD 209458. Thus, the overall light curve we will obtain on TrES-1 will still be stunning, with some 330 exposures in total over the three, five-orbit visits with each exposure at a S/N of 7, 150. The original STIS observations also carried a more risky goal of detecting the planet atmosphere through increased depth of the Sodium D line during transit. At a resolution of 140 compared to 5, 500 for the STIS medium resolution grating, we do not expect to be able to do this component of the science. Nor is it likely that the redder parts of the grism spectrum, where the S/N per resolution element will be down, and fringing will exist, can provide atmospheric results via molecular features. The broad bandpass coverage will provide extra constraints via quantifying color dependence of limb darkening. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments 10441( 3) - 11/02/04 13:59 - [ 3] ------------------- The scheduling for these visits will be tight. The three visits each have a 20 minute phase window, offset from each other by 20 minute centers. ------------------------------------------------------------------------------------ 10441( 3) - 11/02/04 13:59 - [ 4] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 TRES1 STAR, K V-IV RA=19H 4M 09.89S +/- 0.01S, J2000 V = 11.79+/-0.05 DEC=36D 37' 57.7" +/-0.1", B-V = 0.78 PLATE-ID=037K Coordinate Source: GUIDE_STAR_CATALOG Comments: Extrasolar planet host star. Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 1982.39 -0.0035 -0.022 0.0 10441( 3) - 11/02/04 13:59 - [ 5] Visit: 01 Visit Priority: Visit Requirements: PERIOD 3.030065 D AND ZERO-PHASE JD2453186.806 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| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 TRES1 ACS/HRC ACCUM HRC-512 F555W GAIN=4,CR-SPLIT=NO 1 1.0 S POS TARG -0.6,+0.9; PHASE 0.9315 TO 0.9361 Comments: POS TARG to center 0th order and end of first order G800L within subarray. ------------------------------------------------------------------------------------------------------------------------------------ 20 TRES1 ACS/HRC ACCUM HRC-512 G800L GAIN=2,CR-SPLIT=NO, 20 95 S POS TARG -0.6,+0.9 AUTOIMAGE=NO Comments: starting spectral time series ------------------------------------------------------------------------------------------------------------------------------------ 30 TRES1 ACS/HRC ACCUM HRC-512 G800L GAIN=2,CR-SPLIT=NO, 22 95 S SEQ 30 NON-INT; POS TARG AUTOIMAGE=NO -0.6,+0.9 ------------------------------------------------------------------------------------------------------------------------------------ 40 TRES1 ACS/HRC ACCUM HRC-512 G800L GAIN=2,CR-SPLIT=NO, 22 95 S SEQ 40 NON-INT; POS TARG AUTOIMAGE=NO -0.6,+0.9 ------------------------------------------------------------------------------------------------------------------------------------ 50 TRES1 ACS/HRC ACCUM HRC-512 G800L GAIN=2,CR-SPLIT=NO, 22 95 S SEQ 50 NON-INT; POS TARG AUTOIMAGE=NO -0.6,+0.9 ------------------------------------------------------------------------------------------------------------------------------------ 60 TRES1 ACS/HRC ACCUM HRC-512 G800L GAIN=2,CR-SPLIT=NO, 22 95 S SEQ 60 NON-INT; POS TARG AUTOIMAGE=NO -0.6,+0.9 ------------------------------------------------------------------------------------------------------------------------------------ 10441( 3) - 11/02/04 13:59 - [ 6] Visit: 02 Visit Priority: Visit Requirements: PERIOD 3.030065 D AND ZERO-PHASE JD2453186.806 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| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 TRES1 ACS/HRC ACCUM HRC-512 F435W GAIN=4,CR-SPLIT=NO 1 1.0 S POS TARG -0.6,+0.9; PHASE 0.9361 TO 0.9407 Comments: POS TARG to center 0th order and end of first order G800L within subarray. ------------------------------------------------------------------------------------------------------------------------------------ 20 TRES1 ACS/HRC ACCUM HRC-512 G800L GAIN=2,CR-SPLIT=NO, 20 95 S POS TARG -0.6,+0.9 AUTOIMAGE=NO Comments: starting spectral time series ------------------------------------------------------------------------------------------------------------------------------------ 30 TRES1 ACS/HRC ACCUM HRC-512 G800L GAIN=2,CR-SPLIT=NO, 22 95 S SEQ 30 NON-INT; POS TARG AUTOIMAGE=NO -0.6,+0.9 ------------------------------------------------------------------------------------------------------------------------------------ 40 TRES1 ACS/HRC ACCUM HRC-512 G800L GAIN=2,CR-SPLIT=NO, 22 95 S SEQ 40 NON-INT; POS TARG AUTOIMAGE=NO -0.6,+0.9 ------------------------------------------------------------------------------------------------------------------------------------ 50 TRES1 ACS/HRC ACCUM HRC-512 G800L GAIN=2,CR-SPLIT=NO, 22 95 S SEQ 50 NON-INT; POS TARG AUTOIMAGE=NO -0.6,+0.9 ------------------------------------------------------------------------------------------------------------------------------------ 60 TRES1 ACS/HRC ACCUM HRC-512 G800L GAIN=2,CR-SPLIT=NO, 22 95 S SEQ 60 NON-INT; POS TARG AUTOIMAGE=NO -0.6,+0.9 ------------------------------------------------------------------------------------------------------------------------------------ 10441( 3) - 11/02/04 13:59 - [ 7] Visit: 03 Visit Priority: Visit Requirements: PERIOD 3.030065 D AND ZERO-PHASE JD2453186.806 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| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 TRES1 ACS/HRC ACCUM HRC-512 F814W GAIN=4,CR-SPLIT=NO 1 1.0 S POS TARG -0.6,+0.9; PHASE 0.9407 TO 0.9453 Comments: POS TARG to center 0th order and end of first order G800L within subarray. ------------------------------------------------------------------------------------------------------------------------------------ 20 TRES1 ACS/HRC ACCUM HRC-512 G800L GAIN=2,CR-SPLIT=NO, 20 95 S POS TARG -0.6,+0.9 AUTOIMAGE=NO Comments: starting spectral time series ------------------------------------------------------------------------------------------------------------------------------------ 30 TRES1 ACS/HRC ACCUM HRC-512 G800L GAIN=2,CR-SPLIT=NO, 22 95 S SEQ 30 NON-INT; POS TARG AUTOIMAGE=NO -0.6,+0.9 ------------------------------------------------------------------------------------------------------------------------------------ 40 TRES1 ACS/HRC ACCUM HRC-512 G800L GAIN=2,CR-SPLIT=NO, 22 95 S SEQ 40 NON-INT; POS TARG AUTOIMAGE=NO -0.6,+0.9 ------------------------------------------------------------------------------------------------------------------------------------ 50 TRES1 ACS/HRC ACCUM HRC-512 G800L GAIN=2,CR-SPLIT=NO, 22 95 S SEQ 50 NON-INT; POS TARG AUTOIMAGE=NO -0.6,+0.9 ------------------------------------------------------------------------------------------------------------------------------------ 60 TRES1 ACS/HRC ACCUM HRC-512 G800L GAIN=2,CR-SPLIT=NO, 22 95 S SEQ 60 NON-INT; POS TARG AUTOIMAGE=NO -0.6,+0.9 ------------------------------------------------------------------------------------------------------------------------------------ 10441( 3) - 11/02/04 13:59 - [ 8] Summary Form for Proposal 10441 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures HRC-512 ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/HRC ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters GAIN=4 CR-SPLIT=NO GAIN=2 AUTOIMAGE=NO ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO/DD ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PERIOD 3.030065 D AND ZERO-PHASE JD2453186.806 POS TARG -0.6,+0.9; PHASE 0.9315 TO 0.9361 POS TARG -0.6,+0.9 SEQ 30 NON-INT; POS TARG -0.6,+0.9 SEQ 40 NON-INT; POS TARG -0.6,+0.9 SEQ 50 NON-INT; POS TARG -0.6,+0.9 SEQ 60 NON-INT; POS TARG -0.6,+0.9 POS TARG -0.6,+0.9; PHASE 0.9361 TO 0.9407 POS TARG -0.6,+0.9; PHASE 0.9407 TO 0.9453 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F555W G800L F435W F814W ------------------------------------------------------------------------------------------------------------------------------------ Target Names TRES1 ------------------------------------------------------------------------------------------------------------------------------------