7483( 13) - 11/04/97 12:51 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 7483 Version: 13 Check-in Date: 04-Nov-1997 12:50:57 1.Proposal Title: The Nature of T Tau S ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 7 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: MICHAL SIMON State University of New York, Stony Brook CoI: Lisa Prato State University of New York N CoI: Karl Stapelfeldt Jet Propulsion Laboratory N ------------------------------------------------------------------------------------ 5. Abstract We propose to make spectroscopic observations of T Tau S, the IR luminous component of the T Tau binary, in order to establish the nature of the obscured star, to probe the aftermath of its flare, and to estimate the extinction and the wavelength dependence of the dust in the circumstellar disk. ------------------------------------------------------------------------------------ 7483( 13) - 11/04/97 12:51 - [ 2] Observations Description ------------------------ Our proposed observation requires STIS operating with the CCD detector, the G750L grating, the 52X0.2F1 slit, and the telescope positioned so that the slit is oriented along the position angle of the T Tau binary, 178^degrees. We estimate about 53 minutes of an orbit will be available. After acquiring the visible light star, T Tau N, we will perform an acquisition peakup to center it within the 0.2'' slit. The relevant magnitudes of T Tau N are V =10, R =9.2, and I = 8.5 mag (Herbig and Bell 1988). Because T Tau N is >= 5000 time brighter than T Tau S at R, we need to determine whether any of its light is spread in the instrument, at a very low level, to the 0.7'' angular separation of T Tau S. We will do this in two ways. First, we will take a one 1 second reference spectrum of T Tau N; this will reach S/N>50 over the entire spectrum. We choose this integration time to guard against saturating at HAlpha. For EW(HAlpha) = 60 Angstrom (Herbig and Bell 1988), the counts in the line will still fall more than a factor of 10 below the full well limit. We will then move T Tau N behind the 0.4'' coronographic bar. T Tau S will be located 0.7'' to the S along the slit. We estimate that 26 minutes will remain at this point in Orbit 1 for science exposure of T Tau S. Allowing 2 minutes for CRSPLT=4, we expect approximately 24 minutes (1440 sec) of integration. Analysis of the ``sky'' observation, 0.7'' north of the coronographic bar along the slit, and comparison with the T Tau N reference spectrum, will provide a direct measure of the level of contamination. If present, we will subract the contamination from the T Tau S spectrum. The observations in Orbits 2 and 3 will be identical: we will obtain the reference spectrum of T Tau N in each before occulting it behind the coronographic bar. Guide star acquisition will be about 3 minutes faster however, increasing the time for observation of T Tau S to 29 minutes. With CRSPLT=4 we expect approximately 27 minutes (1620 seconds) of integration, for total of ~ 4680 seconds in the 3 orbits. Real Time Justification ----------------------- Since T Tau is in the Taurus dark cloud region guide star availability is, in principle, an intrinsic problem. HST has, however, already observed T Tau with WFPC2 and the GHRS, so we anticipate that guide stars and time-windows for the STIS observations can be found. We require that the orientation of the slit lie along the position angle of the T Tau N - S binary. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Media: DAT Blocking Factor: 10 Ship To: PI_Address Ship Via: Email: ------------------------------------------------------------------------------------ 7483( 13) - 11/04/97 12:51 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 T-TAU STAR, T Tauri Star RA=04H 21M 59.41S +/- J2000 V = 9+/-1 0.1S,DEC=19D 32' 7.0" +/- B-V = 1.2 1.0",PLATE-ID=000P Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 1982 .0011 -.013 0.0 7483( 13) - 11/04/97 12:51 - [ 4] Visit: 01 Visit Priority: Visit Requirements: ORIENT 42D TO 43D SCHED 70% BETWEEN 1-DEC-1997 AND 31-DEC-1997 On Hold Comments: Additional Comments: Orientation chosen to relate slit position to binary orientation. Coordinated with groundbased observations. Time window will be narrowed to better suit coordination. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 T-TAU STIS/C ACQ F25ND3 MIRROR ACQTYPE=POINT 1 0.1 S ONBOARD ACQ FOR 20-60 CD Comments: Orbit #1 ------------------------------------------------------------------------------------------------------------------------------------ 20 T-TAU STIS/C ACCUM 52X0.2F G750L 7751 CR-SPLIT=4 1 35 M END ORBIT CD 1 Comments: Spectrum of T-TAU S w/ T-TAU N under fiducial Orbit #1 ------------------------------------------------------------------------------------------------------------------------------------ 30 T-TAU STIS/C ACCUM 52X0.2F G750L 7751 CR-SPLIT=4 1 42 M END ORBIT CD 1 Comments: Spectrum of T-TAU S w/ T-TAU N under fiducial Orbit #2 ------------------------------------------------------------------------------------------------------------------------------------ 40 NONE STIS/C ACCUM 52X0.2F G750L 7751 LAMP=TUNGSTEN,CR-SPLIT=NO,GAIN=4, 2 25 S CD 1 BINAXIS1=1,BINAXIS2=1 Comments: Fringe flat for T-TAU S observations Flat should execute during occultation Orbit #2 ------------------------------------------------------------------------------------------------------------------------------------ 50 T-TAU STIS/C ACCUM 52X0.2F G750L 7751 CR-SPLIT=4 1 36 M CD 1 Comments: Spectrum of T-TAU S w/ T-TAU N under fiducial Orbit #3 ------------------------------------------------------------------------------------------------------------------------------------ 60 T-TAU STIS/C ACCUM 52X0.2 G750L 7751 1 1 S CD Comments: Spectrum of T-TAU N at center of slit Orbit #3 ------------------------------------------------------------------------------------------------------------------------------------ 62 T-TAU STIS/C ACCUM 52X0.2 G750L 7751 1 1 S CD Comments: Spectrum of T-TAU N at center of slit Orbit #3 ------------------------------------------------------------------------------------------------------------------------------------ 64 T-TAU STIS/C ACCUM 52X0.2 G750L 7751 1 0.4 S END ORBIT CD Comments: Spectrum of T-TAU N at center of slit Orbit #3 ------------------------------------------------------------------------------------------------------------------------------------ 70 NONE STIS/C ACCUM 0.3X0.0 G750L 7751 LAMP=TUNGSTEN,CR-SPLIT=NO,GAIN=4, 2 56 S CD 9 BINAXIS1=1,BINAXIS2=1 Comments: Fringe flat for T-TAU N observation Flat should execute during occultation Orbit #3 ------------------------------------------------------------------------------------------------------------------------------------ 7483( 13) - 11/04/97 12:51 - [ 5] Summary Form for Proposal 7483 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT CR-SPLIT=4 BINAXIS2=1 BINAXIS1=1 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 42D TO 43D SCHED 70% BETWEEN 1-DEC-1997 AND 31-DEC-1997 ONBOARD ACQ FOR 20-60 END ORBIT ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G750L ------------------------------------------------------------------------------------------------------------------------------------ Target Names T-TAU NONE ------------------------------------------------------------------------------------------------------------------------------------