12907( 4) - 11-Jul-2012 19:32:13 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 12907 Version: 4 Check-in Time: 11-Jul-2012 19:32:13 STScI Edit Number: 1 Title Stationary components in the DG Tau jet: A new challenge for jet models? ------------------------------------------------------------------------------------ Type Cycle GO 20 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Peter Christian Schneider Universitat Hamburg, Hamburger Sternwarte Y CoI: Dr. Gregory J. Herczeg Peking University N CoI: Prof. Manuel Guedel University of Vienna N CoI: Dr. Jochen Eisloeffel Thuringer Landessternwarte Tautenburg N (TLS) CoI: Dr. Hans Moritz Guenther Smithsonian Institution Astrophysical N Observatory CoI: Prof. Jurgen H.M.M. Schmitt Universitat Hamburg, Hamburger Sternwarte N CoI: Dr. Jan Robrade Universitat Hamburg, Hamburger Sternwarte N CoI: Dr. Francesca Bacciotti Osservatorio Astrofisico di Arcetri N CoI: Mr. Lorenzo Maurri Osservatorio Astrofisico di Arcetri N CoI: Dr. Linda Podio Institut de Planetologie et N d'Astrophysique de Grenoble ------------------------------------------------------------------------------------ Abstract Jets from young stellar objects play an important role for star formation as they can regulate the angular momentum balance of the system. The jet from the classical T Tauri star DG Tau stands out due to its stationary very high temperature plasma (T>10^6 K) very close to the driving source observed in deep multi-epoch X-ray observations. This X-ray emitting jet material is significantly hotter than previously studied material and not predicted by current jet theories. Our HST observations during Cycle 18 reveal intermediate temperature FUV C IV emission (T~10^5 K) co-spatial with the X-rays and indications for a further stationary low temperature component (T~10^4 K). In order to investigate the nature of the stationary component(s), we propose to obtain new epoch STIS long-slit spectra with the slit oriented along the jet axis. By studying the evolution of the individual emission components we will determine if C IV and X-ray emission are physically connected and constrain their respective heating processes. We will also test if further stationary components exist in addition to the known moving emission regions which result from episodic mass-loss events. ------------------------------------------------------------------------------------ Observations Description ------------------------ The goal of the proposed observations is to spatially resolve the kinematics of the intermediate (T = 10^5 K) and low temperature (T = 10^4 K) material within the DG Tau jet. No stellar FUV emission has been detected in the previous observations, so that all FUV emission comes from the jet. The interemediate temperature plasma will be traced by C IV emission at ~1550 A and we dedicate three orbits for the associated STIS G140M exposures. For the comparison of the C IV emission with the lower temperature ionic emission one additional orbit 12907( 4) - 11-Jul-2012 19:32:13 - [ 2] with the STIS G750M grating is needed to measure the current forbidden line emission. The position angle of the jet (PA=226 deg) is known from previous observations (HST and ground based AO). A tolerance of ±1deg in position angle is acceptable for this jet. The 52 × 0. 2 slit will include virtually all of the relevant high-velocity emission. Setting the G140M grating to the wavelength range 1513–1567 ̊ includes the C iv emission line doublet (1548 and 1551 A) and ro-vibrationally excited H2 emission at 1521 A and 1525 A. The FUV exposures will be dithered along the slit to identify hot pixel (dither amplitude of 0.5"). A short ACQ exposure (STIS CCD with F28X50LP filter) is needed to center the jet in the slit. As the target is acquired with the CCD, we will take a short G430L exposure prior to the FUV observations in order to check the current accretion state of DG Tau. The two visits (optical and FUV) should be performed within 15 days to ensure that the jet evolution is negligible between the exposures. Detector Safety: We know from our last FUV observations of DG Tau that the expected global (< 200 counts s−1 ) and local count-rates (<0.1 counts/sec/pix) are significantly below the STIS brighness limits. The slit orientation is identical to our last program and no other (bright) sources will illuminate the slit. Further information on surrounding sources can be found in the observation description of Prop 12199. In particular, no other bright sources are known. As discussed for Prop-ID 12199, the two unknown BOT sources (N9QL001759, N9QL009269) do not violate any brightness limit. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 12907( 4) - 11-Jul-2012 19:32:13 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 V-DG-TAU STAR, JET, T TAURI RA=04H27M4.7000S +/- 0.1", J2000 V = 12.5 +/- 1.1 The C IV is about STAR, YSO DEC=+26D06'16.10" +/- 0.4" 2e-14 erg/s/cm^2. Reference Frame: ICRS Comments: This object was generated by the targetselector and retrieved from the SIMBAD database. The alternate name is also from the SIMBAD database. The target uncertainties pertain to the difference between the expected, proper-motion corrected position from Ducourant et al. (2005) and the 2MASS position for epoch 2012 given here. We regard this as the uncertainty since both values do not agree for the same epoch. ------------------------------------------------------------------------------------------------------------------------------------ 12907( 4) - 11-Jul-2012 19:32:13 - [ 4] Patterns ------------------------------------------------------------------------------------------------------------------------------------ Pattern_Number: 1 Primary_Pattern Secondary_Pattern Pattern_Type STIS-ALONG-SLIT Pattern_Purpose DITHER Number_Of_Points 3 Point_Spacing 0.5 Line_Spacing Coordinate_Frame POS-TARG Pattern_Orient 90.0 Angle_Between_Sides Center_Pattern NO Pattern_Comments: This pattern is applied to the FUV observations to dither the emission along the slit. The dither amplitude of 0.5" places the emission (size about 0.5") at disjunct regions on the detector during the three dither positions. Each dither position should be applied to a different orbit. Centering the pattern places the emission at the nominal center of the detector during the longer exposure of the second orbit. ------------------------------------------------------------------------------------------------------------------------------------ 12907( 4) - 11-Jul-2012 19:32:13 - [ 5] Visit: 01 Visit Requirements: SCHED 100%; ORIENT 90D TO 92 D; ORIENT 270D TO 272 D; GROUP 01, 02 WITHIN 15D On Hold Comments: Additional Comments: This visit is dedicated to the FUV MAMA exposures (G140M) and the short G430L optical spectrum. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 V-DG-TAU STIS/CCD ACQ F28X50LP MIRROR ACQTYPE=POINT 1 0.2 S GS ACQ SCENARIO BASE1B3 ------------------------------------------------------------------------------------------------------------------------------------ 2 V-DG-TAU STIS/CCD ACCUM 52X0.2 G430L 4300 CR-SPLIT=2 1 360 S Comments: CR-SPLIT=2 should be sufficient for cosmic ray removal since the exposure time is sufficiently short. ------------------------------------------------------------------------------------------------------------------------------------ 3 V-DG-TAU STIS/FUV TIME-TA 52X0.2 G140M 1540 BUFFER-TIME=1000 1 1000 S PATTERN 1 3 -MAMA G see below Comments: The FUV observations will be dithered along the slit (dither amplitude 0.5") for an improved hot pixel removal. ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ V-DG-TAU 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A V-DG-TAU 2 STIS/CCD ACCUM 52X0.2 G430L 4300 none none none 1 1 N/A V-DG-TAU 2 STIS/CCD ACCUM 52X0.2 G430L 4300 none none none 2 1 N/A V-DG-TAU 3 STIS/FUV TIME-TA 52X0.2 G140M 1540 1 none none none 1 1441.0 S -MAMA G V-DG-TAU 3 STIS/FUV TIME-TA 52X0.2 G140M 1540 2 none none none 2 2761.0 S -MAMA G V-DG-TAU 3 STIS/FUV TIME-TA 52X0.2 G140M 1540 3 none none none 3 2761.0 S -MAMA G 12907( 4) - 11-Jul-2012 19:32:13 - [ 6] Visit: 02 Visit Requirements: SCHED 100%; ORIENT 90D TO 92 D; ORIENT 270D TO 272 D; GROUP 02, 01 WITHIN 15D On Hold Comments: Additional Comments: This visit is dedicated to the G750M long-slit spectrum. No dithering is applied to these exposures. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 V-DG-TAU STIS/CCD ACQ F28X50LP MIRROR ACQTYPE=POINT 1 0.2 S GS ACQ SCENARIO BASE1B3 ------------------------------------------------------------------------------------------------------------------------------------ 2 V-DG-TAU STIS/CCD ACCUM 52X0.2 G750M 6581 CR-SPLIT=3 1 3000 S see below ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ V-DG-TAU 1 STIS/CCD ACQ F28X50LP MIRROR none none none none 1 N/A V-DG-TAU 2 STIS/CCD ACCUM 52X0.2 G750M 6581 none none none 1 1 691.0 S V-DG-TAU 2 STIS/CCD ACCUM 52X0.2 G750M 6581 none none none 2 1 692.0 S V-DG-TAU 2 STIS/CCD ACCUM 52X0.2 G750M 6581 none none none 3 1 692.0 S 12907( 4) - 11-Jul-2012 19:32:13 - [ 7] Summary Form for Proposal 12907 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures 52X0.2, F28X50LP ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD, STIS/FUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM, ACQ, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT, BUFFER-TIME=1000, CR-SPLIT=2, CR-SPLIT=3 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements GROUP 01, 02 WITHIN 15D, GROUP 02, 01 WITHIN 15D, GS ACQ SCENARIO BASE1B3, ORIENT 270D TO 272 D, ORIENT 90D TO 92 D, PATTERN 1 3, SCHED 100% ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G140M, G430L, G750M, MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names V-DG-TAU ------------------------------------------------------------------------------------------------------------------------------------