8132( 4) - 04/04/00 09:57 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 8132 Version: 4 Check-in Date: 30-Mar-2000 13:56:37 1.Proposal Title: The Nature of T Tauri and Herbig Ae/Be Star Winds ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 8 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Thomas Ray Dublin Institute For Advanced Studies CoI: Dr. Jochen Eisloeffel Thueringer Landessterwarte Tautenburg N CoI: Dr. Reinhard Mundt MPI for Astronomy, Heidelberg N CoI: Dr. Chris Davis Joint Astronomy Center N ------------------------------------------------------------------------------------ 5. Abstract The forbidden line emission, of what are probably the youngest classical T Tauri stars and Herbig Ae/Be stars, is often characterised by two radial velocity components. The so-called high velocity component (HVC) is thought to be a jet close to the source since its velocity is normally found to coincide with that of any associated, and extended, Herbig-Haro type jet. In comparison very little is known about the low velocity component (LVC). In this study, we will carry out a detailed investigation of the outflows from the classical T Tauri star RW Aur and the Herbig Ae/Be star LkHAlpha 233 using long-slit spectroscopic imaging. This technique will provide both 2-D intensity and radial velocity data for the HVC and LVC of these flows. Our targets are ideal in that there is very little extinction towards either of these young stellar objects (YSOs) thereby allowing us to study the morphology and dynamics of the innermost regions (<= 1'') of their outflows. The observations wil l be used to address a number of fundamental questions that are common to outflows from both low and intermediate mass young stars. What, for example, is the origin of the LVC, which is much more compact (<= 1'') than the jet? The LVC is often neglected in outflow models although it may be some form of poorly collimated disk wind. To test this idea, the superior resolution of the HST is required. What is the velocity, temperature, ionization fraction and density of these flows on scales of 0.1''--2'? Can we find evidence for entrainment and velocity variations close to the source? Finally by spectroscopically imaging along the extended outflow (jet) direction, we should also be able to examine, for example, what the transverse velocity profile of a YSO jet looks like. Is there evidence for an extensive boundary layer? How do the fundamental parameters mentioned above, such as ionization fraction, change along the jet? ------------------------------------------------------------------------------------ 8132( 4) - 04/04/00 09:57 - [ 2] Observations Description ------------------------ Spectroscopic imaging of LkHAlpha 233 and RW Tau will be carried out using the G750M STIS grating at a central wavelength of 6581 Angstroms. The spectrum will thus cover the range from 6295 Angstroms to 6867 Angstroms allowing us to obtain 2-D intensity/velocity data in HAlpha and all of the strong red forbidden emission lines. The direction of the extended outflows from LkHAlpha233 and RW Tau are well known and the slit (with a width of 0.1'') will be oriented at these position angles. To obtain the 2-D intensity velocity images, while at the same time properly sampling the HST PSF, we propose to use 7 closely spaced parallel slit positions for each target. The central slit position will directly cut through the star while the other 6 will be offset perpendicular to the outflow direction in steps of +/-0.07''. More slit positions were not judged necessary in the transverse direction to the flows since the HVC and the LVC in both cases is spatially not extended by more than ~ 0.3'' in this direction. Our choice of exposure time is largely dictated by [NII] Lambda6583 fluxes. This is an important line for diagnostic purposes which we will use to obtain ionization fractions in the LVCs, the HVCs and the extended jets. We expect a [NII] Lambda6583 surface brightness of about 2^-13 erg s^-1 cm^-2 arcsec^-2 AA^-1 (for a 3 Angstrom broad line) for LkHAlpha 233 and a somewhat higher value for RW Aur. Using the STIS Exposure Time Calculator, one finds that for an effective total integration time of 1800 sec (3 way cosmic ray split of one orbit i.e.\ 3x600s) a S/N ratio of about 90 is obtained for this line in regions free of stellar continuum emission. The S/N ratio, however, will decrease in both cases nearer the star, the effect being more marked in the case of RW Aur, where the stellar continuum becomes the dominant noise source. Real Time Justification ----------------------- none none Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Paper Products: NO Media: ELECTRONIC Blocking Factor: 10 Ship To: PI_Address Ship Via: Email: ------------------------------------------------------------------------------------ 8132( 4) - 04/04/00 09:57 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 RW-AUR STAR, T TAURI STAR, RA=05H 7M 49.57S +/- 0S, DEC=30D J2000 V = 10.34 JET, WIND, EJECTA 24' 5.2" +/- 0" TYPE=G5V SURF-LINE(6583)=8e-13 W-LINE(6583)=2.0+/-1.0 Comments: HIPPARCOS position used. Note this is a triple system. Our target is the primary (A). B and C are positioned at P.A.=256 and 1".4 away. B is 2-3 magnitudes fainter than A and C is fainter still. 2 LKHALPHA-233 STAR, HERBIG AE/BE, RA=22H 34M 40.94S +/- 0S, J2000 V = 11.54 JET, WIND, EJECTA DEC=40D 40' 3.4" +/- 0" TYPE=AV SURF-LINE(6583)=6e-13 W-LINE(6583)=2.0+/-1.0 8132( 4) - 04/04/00 09:57 - [ 4] Visit: 01 Visit Priority: Visit Requirements: ORIENT 175D TO 175D ORIENT 355D TO 355D 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 RW-AUR STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 0.1 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 2 RW-AUR STIS/C ACQ/PEA 52X0.1 MIRROR 1 0.1 S CD K ------------------------------------------------------------------------------------------------------------------------------------ 3 RW-AUR STIS/C ACCUM 52X0.1 G750M 6581 CR-SPLIT=NO,PATTERN=PERP-TO-SLIT, 6 6 M POS TARG -0.14, 0.0 CD NUM-POS=3,STEP-SIZE=0.14, PATTERN-DIRECTION=PLUS ------------------------------------------------------------------------------------------------------------------------------------ 8132( 4) - 04/04/00 09:57 - [ 5] Visit: 02 Visit Priority: Visit Requirements: ORIENT 175D TO 175D ORIENT 355D TO 355D 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 RW-AUR STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 0.1 S CD P ------------------------------------------------------------------------------------------------------------------------------------ 2 RW-AUR STIS/C ACQ/PEA 52X0.1 MIRROR 1 0.1 S CD K ------------------------------------------------------------------------------------------------------------------------------------ 3 RW-AUR STIS/C ACCUM 52X0.1 G750M 6581 CR-SPLIT=NO,PATTERN=PERP-TO-SLIT, 6 6 M POS TARG -0.21, 0.0 CD NUM-POS=4,STEP-SIZE=0.14, PATTERN-DIRECTION=PLUS ------------------------------------------------------------------------------------------------------------------------------------ 8132( 4) - 04/04/00 09:57 - [ 6] Visit: 03 Visit Priority: Visit Requirements: ORIENT 115D TO 115D ORIENT 295D TO 295D 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 LKHALPHA-23 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 1 S ONBOARD ACQ FOR 2 3 CD P ------------------------------------------------------------------------------------------------------------------------------------ 2 LKHALPHA-23 STIS/C ACQ/PEA 52X0.1 MIRROR 1 1 S ONBOARD ACQ FOR 3 3 CD K ------------------------------------------------------------------------------------------------------------------------------------ 3 LKHALPHA-23 STIS/C ACCUM 52X0.1 G750M 6581 CR-SPLIT=2,PATTERN=PERP-TO-SLIT, 1 35 M POS TARG -0.14, 0.0 3 CD NUM-POS=3,STEP-SIZE=0.14, PATTERN-DIRECTION=PLUS ------------------------------------------------------------------------------------------------------------------------------------ 8132( 4) - 04/04/00 09:57 - [ 7] Visit: 04 Visit Priority: Visit Requirements: ORIENT 115D TO 115D ORIENT 295D TO 295D 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 ------------------------------------------------------------------------------------------------------------------------------------ 1 LKHALPHA-23 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 1 S ONBOARD ACQ FOR 2 3 CD P ------------------------------------------------------------------------------------------------------------------------------------ 2 LKHALPHA-23 STIS/C ACQ/PEA 52X0.1 MIRROR 1 1 S ONBOARD ACQ FOR 3 3 CD K ------------------------------------------------------------------------------------------------------------------------------------ 3 LKHALPHA-23 STIS/C ACCUM 52X0.1 G750M 6581 CR-SPLIT=2,PATTERN=PERP-TO-SLIT, 1 35 M POS TARG -0.21, 0.0 3 CD NUM-POS=4,STEP-SIZE=0.14, PATTERN-DIRECTION=PLUS ------------------------------------------------------------------------------------------------------------------------------------ 8132( 4) - 04/04/00 09:57 - [ 8] Summary Form for Proposal 8132 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F28X50LP 52X0.1 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACQ/PEAK ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT PATTERN-DIRECTION=PLUS STEP-SIZE=0.14 NUM-POS=3 NUM-POS=4 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 175D TO 175D ORIENT 355D TO 355D POS TARG -0.14, 0.0 POS TARG -0.21, 0.0 ORIENT 115D TO 115D ORIENT 295D TO 295D ONBOARD ACQ FOR 2 ONBOARD ACQ FOR 3 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G750M ------------------------------------------------------------------------------------------------------------------------------------ Target Names RW-AUR LKHALPHA-233 ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 6581 ------------------------------------------------------------------------------------------------------------------------------------