5875( 7) - 08/04/95 14:47 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 5875 Version: 7 Check-in Date: ********** 1.Proposal Title: Hot Winds in T Tauri Stars? ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Cool Stars GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Gibor Basri University of California CoI: Frederick Walter State University of New York at Stony Y Brook CoI: Lee Hartmann Harvard-Smithsonian Center for N Astrophysics CoI: Christopher Johns University of Texas N ------------------------------------------------------------------------------------ 6. Abstract Interest in T Tauri stars is high because they are surrounded by accretion disks like the solar nebula, and because they provide the best view of the mass loss mechanism responsible for bipolar outflows, protostellar jets, and the winds which play a big role in fixing the angular momentum and possibly the mass of the newly formed star. In Cycle 2 we obtained the first good high resolution observations of the ultraviolet emission lines formed in the interface between star and disk. These demonstrated that emission arises both in narrow components likely confined by the stellar magnetic field, and in broad components diagnostic of the accretion disk interaction with the star. There were several surprises; we did not expect material at 10^5K to so closely resemble the optical profiles. Especially tantalizing are hints that the wind itself may contain such hot material, possibly even optically thick. This has strong implications for the mechanism driving the outflow. In particular it may be difficult to produce such material in the magnetocentifugally driven winds which currently hold favor. We propose a program aimed specifically at the question of to what extent hot material exists in T Tauri winds. We will examine stars selected specifically for their wind diagnostics, and expand our coverage of stellar masses. We will also examine for the first time pre--main sequence stars without disks, to disentangle purely stellar phenomena. ------------------------------------------------------------------------------------ 5875( 7) - 08/04/95 14:47 - [ 2] Observations Description ------------------------ Our observing program is constructed to look at stars in which the suggestion of a wind is strong, and which have strong UV emission lines. We expand the coverage of stellar spectral types; one might expect real differences if the star has a lot to do with the wind, and minimal differences if the disk is primarily responsible. DG Tau is a target with a strong P Cygni profile in H Alpha. A recent HST imaging experiment^14 has shown that a highly collimated jet can be seen already in place down to a few AU from this star. It is an even stronger wind case than DR Tau. If our fundamental premise is correct, the evidence for blueshifted absorption in hot lines should be strongest in this target. We would also like to repeat DR Tau for two reasons (see Duplications section). Another bright target is T Tau itself (K1). It (naturally) shows a ``classical'' H Alpha profile with blueshifted absorption (not down to the continuum), and we have good optical coverage of it. Despite the complexities of the system in the infrared, the UV emission is likely to come almost entirely from the primary star. Finally, we can no longer put off observing examples of pre--main sequence stars without a disks. This is particularly important in light of the Si IV anomaly described in the section on Related HST Programs; it is important to understand whether it can have a stellar origin. In general we must know what young stars can produce on their own, before interpreting the profiles from disk systems. A good example of this is the report^15 of low broad wings in AU Mic (dMe) which are ascribed to microflaring; such wings in CTTS would be interpreted as due to turbulent accretion. We will observe a diskless star analogous to our low mass Taurus CTTS (HBC 388). In all cases we propose to observe the C IV, Si IV, and Mg II spectral regions as before. The main science is obvious from the description of our previous program. We have estimated exposure times based on our previous exposures for DR Tau and IUE measurements of line flux for the other stars. The orbit requirements given should yield spectra of the quality of our RW Aur spectra in almost all cases. We have allowed for the fact that there are broad components in most lines. It is clear from the required exposures that HST/GHRS is the only instrument capable of doing this project. We will again take WAVECAL exposures; the need for this is graphically demonstrated by the odd velocity structure in Si IV described below. Real Time Justification ----------------------- As in our last program, we will make every attempt to obtain supporting ground- -based observations. These will preferably be high dispersion spectra, although low dispersion spectra or photometry are also valuable. While impossible to insure pre--scheduled observatory time, we were able to make coude auxillary observations on short notice, and prevail upon our friends to make supporting observations. The same facilities at Lick Observatory will be available again, and additionally CJ has access to the spectroscopes at McDonald Observatory. Automated photometric telescopes owned by UC Berkeley will be available for photometric monitoring. Finally, we have an ongoing monitoring program for most of the targets that will place them in a longer term context. Calibration Justification ------------------------- We will obtain WAVE observations prior to the Si IV spectra, in order to confirm the anomalous wavelengths we observed last time. Additional Comments ------------------- ------------------------------------------------------------------------------------ 5875( 7) - 08/04/95 14:47 - [ 3] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: Fred Walter*Astronomy Program, Z=2100*Earth and Space Sciences Department*SUNY*Stony Brook NY 11794- 2100 Ship Via: UPS Email: fwalter@astro.sunysb.edu , ------------------------------------------------------------------------------------ 5875( 7) - 08/04/95 14:47 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 DG-Tau STAR RA=4H 27M 4.71S +/- 0.02S, J2000 V=12.01+/-0.3 DEC=26D 06' 16.78" +/- 0.2", B-V=0.93+/-0.1 PLATE-ID=000L Comments: Coordinates are from GSC Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 1983.020 0.0 0.0 0.0 2 DR-Tau STAR RA=4H 47M 6.22S +/- 0.02S, J2000 V=11.2+/-0.2 DEC=16D 58' 43.39" +/- 0.1", B-V=0.64+/-0.1 PLATE-ID=00FI Comments: Coordinates are from GSC Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 1982.959 0.0 0.0 0.0 3 T-Tau STAR RA=4H 21M 59.40S +/- 0.1S, J2000 V=10.30+/-0.7 DEC=19D 32' 7.5" +/- 0.3", PLATE B-V=1.20+/-0.2 -ID=000O Comments: Coordinates are from GSC Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 1982.959 0.0 0.0 0.0 4 HBC388 STAR RA=4H 27M 10.57S +/- 0.01S, J2000 V=10.34+/-0.2 DEC=17D 50' 42.40" +/- 0.2", B-V=0.79+/-0.05 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 0.0 5875( 7) - 08/04/95 14:47 - [ 5] 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 DG-Tau HRS ACQ 2.0 MIRROR-N2 BRIGHT=RETURN,S 1 18S ONBOARD ACQ FOR 12-18 EARCH-SIZE=3 Comments: STEP-TIME=2.0S ------------------------------------------------------------------------------------------------------------------------------------ 12 DG-Tau HRS ACCUM 2.0 G270M 2799 STEP-PATT=5 4 163.2S ------------------------------------------------------------------------------------------------------------------------------------ 14 DG-Tau HRS ACCUM 2.0 G160M 1552 STEP-PATT=5 18 299.2S ------------------------------------------------------------------------------------------------------------------------------------ 15 WAVE HRS ACCUM SC2 G160M 1400 STEP-PATT=3 1 28.8S ------------------------------------------------------------------------------------------------------------------------------------ 16 DG-Tau HRS ACCUM 2.0 G160M 1400 STEP-PATT=5 19 299.2S ------------------------------------------------------------------------------------------------------------------------------------ 17 DG-Tau HRS ACCUM 2.0 G160M 1400 STEP-PATT=5 18 299.2S ------------------------------------------------------------------------------------------------------------------------------------ 18 DG-Tau HRS ACCUM 2.0 G270M 2799 STEP-PATT=5 3 190.4S ------------------------------------------------------------------------------------------------------------------------------------ 5875( 7) - 08/04/95 14:47 - [ 6] 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 DR-Tau HRS ACQ 2.0 MIRROR-N2 BRIGHT=RETURN,S 1 18S ONBOARD ACQ FOR 22-28 EARCH-SIZE=3 Comments: STEP-TIME=2.0S ------------------------------------------------------------------------------------------------------------------------------------ 22 DR-Tau HRS ACCUM 2.0 G270M 2799 STEP-PATT=5 7 163.2S ------------------------------------------------------------------------------------------------------------------------------------ 23 WAVE HRS ACCUM SC2 G160M 1552 STEP-PATT=3 1 28.8S ------------------------------------------------------------------------------------------------------------------------------------ 24 DR-Tau HRS ACCUM 2.0 G160M 1552 STEP-PATT=5 20 299.2S ------------------------------------------------------------------------------------------------------------------------------------ 25 DR-Tau HRS ACCUM 2.0 G160M 1342 STEP-PATT=5 5 299.2S ------------------------------------------------------------------------------------------------------------------------------------ 28 DR-Tau HRS ACCUM 2.0 G270M 2799 STEP-PATT=5 4 163.2S ------------------------------------------------------------------------------------------------------------------------------------ 5875( 7) - 08/04/95 14:47 - [ 7] 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 T-Tau HRS ACQ 2.0 MIRROR-N2 BRIGHT=RETURN,S 1 9S ONBOARD ACQ FOR 32-38 EARCH-SIZE=3 Comments: STEP-TIME=1.0S ------------------------------------------------------------------------------------------------------------------------------------ 32 T-Tau HRS ACCUM 2.0 G270M 2799 STEP-PATT=5 4 108.8S ------------------------------------------------------------------------------------------------------------------------------------ 34 T-Tau HRS ACCUM 2.0 G160M 1342 STEP-PATT=5 5 272S ------------------------------------------------------------------------------------------------------------------------------------ 35 T-Tau HRS ACCUM 2.0 G160M 1497 STEP-PATT=5 5 272S ------------------------------------------------------------------------------------------------------------------------------------ 36 T-Tau HRS ACCUM 2.0 G160M 1552 STEP-PATT=5 4 299.2S ------------------------------------------------------------------------------------------------------------------------------------ 37 WAVE HRS ACCUM SC2 G160M 1400 STEP-PATT=3 1 28.8S ------------------------------------------------------------------------------------------------------------------------------------ 38 T-Tau HRS ACCUM 2.0 G160M 1400 STEP-PATT=5 9 272S ------------------------------------------------------------------------------------------------------------------------------------ 5875( 7) - 08/04/95 14:47 - [ 8] Visit: 04 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 ------------------------------------------------------------------------------------------------------------------------------------ 40 HBC388 HRS ACQ 2.0 MIRROR-N2 BRIGHT=RETURN,S 1 9S ONBOARD ACQ FOR 44-48 EARCH-SIZE=3 Comments: STEP-TIME=1.0S ------------------------------------------------------------------------------------------------------------------------------------ 44 HBC388 HRS ACCUM 2.0 G160M 1552 STEP-PATT=5 18 299.2S ------------------------------------------------------------------------------------------------------------------------------------ 45 WAVE HRS ACCUM SC2 G160M 1400 STEP-PATT=3 1 28.8S ------------------------------------------------------------------------------------------------------------------------------------ 46 HBC388 HRS ACCUM 2.0 G160M 1400 STEP-PATT=5 20 299.2S ------------------------------------------------------------------------------------------------------------------------------------ 48 HBC388 HRS ACCUM 2.0 G270M 2799 STEP-PATT=5 5 217.6S ------------------------------------------------------------------------------------------------------------------------------------ 5875( 7) - 08/04/95 14:47 - [ 9] Summary Form for Proposal 5875 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BRIGHT=RETURN SEARCH-SIZE=3 STEP-PATT=5 STEP-PATT=3 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Cool Stars ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 12-18 ONBOARD ACQ FOR 22-28 ONBOARD ACQ FOR 32-38 ONBOARD ACQ FOR 44-48 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-N2 G270M G160M ------------------------------------------------------------------------------------------------------------------------------------ Target Names DG-Tau WAVE DR-Tau T-Tau HBC388 ------------------------------------------------------------------------------------------------------------------------------------