5880( 0) - 07/18/95 18:26 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 5880 Version: ********** Check-in Date: ********** 1.Proposal Title: OH as a Signpost of Accretion in T Tauri Stars ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Cool Stars GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: George H. Herbig Institute for Astronomy, University of Hawaii CoI: Theodore Simon Institute for Astronomy, University of Y Hawaii ------------------------------------------------------------------------------------ 6. Abstract The H_2O in the interstellar material moving inward in the accretion disk around a T Tauri star, if it is similar to the material in cometary nuclei, will be dissociated by the ultraviolet radiation of the star. A major product is OH, which is detectable in emission by resonance scattering of the 0--0 band near 3100 Angstrom. We propose to examine T Tau and RU Lup for this phenomenon. ------------------------------------------------------------------------------------ 5880( 0) - 07/18/95 18:26 - [ 2] Observations Description ------------------------ We propose to obtain one GHRS spectrum each of T Tauri and RU Lupi, using the G270M grating + D2 detector and the large science aperture. The spectra will cover the 3064--3108 Angstrom\ region, centered on the 0--0 band of OH. Adopting fluxes measured from low dispersion IUE spectra, we estimate that for T Tau a 73-minute integration spanning two orbits of HST will yield a S/N of 17:1 for a single diode. Similarly, a 75-minute integration on RU Lup (also over two orbits) will yield a S/N ratio of 21:1. For T Tau we adopt a flux of 5 * 10^-14 erg cm^-2 s^-1 ang^-1, which yields an expected count rate of 0.075 cts s^-1. For RU Lup the flux is 7 * 10^ -14 erg cm^-2 s^-1 ang^-1, giving a count rate of 0.10 cts s^ -1. If required, a 2-pixel sliding mean can be applied to the data to improve the S/N ratio to 24:1 and 29:1, respectively, at the expense of a lower, smoothed spectral resolution of 0.18 Angstrom. A short observation will also be made of a spectral standard, Eta Cephei. From an IUE flux of 1.5 * 10^-11 erg cm^-2 s^-1 ang^-1 we deduce a GHRS count rate of 22 cts diode^-1 s^-1 and a S/N > 50:1 across the entire 3064- -3108 Angstrom\ region in a 5 minute exposure. Real Time Justification ----------------------- None. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 5880( 0) - 07/18/95 18:26 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 HD284419 STAR, T TAURI STAR RA = 04H 21M 59.42S +/- 0.01S, J2000 V = V = 9.08 +/- 0.40 B-V = 1.19 +/- 0.2 DEC = 19D 32' 6.4" +/- 0.2", +19.1 F-CONT(3100) = 5 +/- 3 E-14 PLATE-ID = 000P Comments: Coordinates are from GSC Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 1982.962 0.0 0.0 0.007 2 HD142560 STAR, T TAURI STAR RA = 15H 56M 42.26S +/- 0.04S, J2000 V = -6.4 V = 11.27 +/- 0.41 B-V = 0.48 +/- 0.2 DEC = -37D 49' 15.7" +/- 0.5", F-CONT(3100) = 7 +/- 3 E-14 PLATE-ID = 02F8 Comments: Coordinates are from GSC Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 1975.423 0.0 0.0 0.008 3 HD198149 STAR, K V-IV RA = 20H 45M 17.24S +/- 0.01S, J2000 V = - V = 3.40 B-V = 0.92 +/- 0.02 DEC = 61D 50' 20.3" +/- 0.1" 87.3 F-CONT(3100) = 1.6 +/- .2 E-11 Comments: Coordinates are from Hipparcos INCA Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000.000 0.0123 0.818 0.071 5880( 0) - 07/18/95 18:26 - [ 4] Visit: 01 Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 HD284419 HRS ACQ 2.0 MIRROR-N2 SEARCH-SIZE = 1 9S ONBOARD ACQuisition FOR 12 3, BRIGHT = RETURN Comments: STEP-TIME = 1.0, EXPECT 5000 COUNTS FOR V=9.90 BASED ON UV FLUX RATIO vs RU LUP ------------------------------------------------------------------------------------------------------------------------------------ 12 HD284419 HRS ACCUM 2.0 G270M 3064- FP-SPLIT = STD, 3 1523.2S 3110 DOPPLER = ON, STEP-PATT = 5 ------------------------------------------------------------------------------------------------------------------------------------ 5880( 0) - 07/18/95 18:26 - [ 5] Visit: 02 Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 20 HD142560 HRS ACQ 2.0 MIRROR-N2 SEARCH-SIZE = 1 9S ONBOARD ACQuisition FOR 22 3, BRIGHT = RETURN Comments: STEP-TIME = 1.0, EXPECT 8000 COUNTS FOR V=10.5 BASED ON PREVIOUS ACQ OF RU LUP ------------------------------------------------------------------------------------------------------------------------------------ 22 HD142560 HRS ACCUM 2.0 G270M 3064- FP-SPLIT = STD, 3 1523.2S 3110 DOPPLER = ON, STEP-PATT = 5 ------------------------------------------------------------------------------------------------------------------------------------ 5880( 0) - 07/18/95 18:26 - [ 6] Visit: 03 Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 30 HD198149 HRS ACQ 2.0 MIRROR-A2 SEARCH-SIZE = 1 9S ONBOARD ACQuisition FOR 32 3, BRIGHT = RETURN Comments: STEP-TIME = 1.0, EXPECT 1800 COUNTS FOR V=3.43 ------------------------------------------------------------------------------------------------------------------------------------ 32 HD198149 HRS ACCUM 2.0 G270M 3064- FP-SPLIT = STD, 2 326.4S 3110 DOPPLER = ON, STEP-PATT = 5 ------------------------------------------------------------------------------------------------------------------------------------ 5880( 0) - 07/18/95 18:26 - [ 7] Summary Form for Proposal 5880 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters SEARCH-SIZE = 3 BRIGHT = RETURN STEP-PATT = 5 DOPPLER = ON FP-SPLIT = STD ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Cool Stars ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQuisition FOR 12 ONBOARD ACQuisition FOR 22 ONBOARD ACQuisition FOR 32 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-N2 G270M MIRROR-A2 ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD284419 HD142560 HD198149 ------------------------------------------------------------------------------------------------------------------------------------