6759( 3) - 02/14/96 12:54 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6759 Version: 3 Check-in Date: 14-Feb-1996 12:45:50 1.Proposal Title: Imaging Arcsecond Scale Jets from Young Stars ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle BINARIES AND STAR FOR GO 6 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Dr. Jochen Eisloeffel Thueringer Landessternwarte Tautenburg CoI: Dr. R. Mundt Max-Planck-Institut fuer Astronomie N CoI: Dr. T. Ray Dublin Institute for Advanced Studies N CoI: Dr. M. Camenzind Landessternwarte, Heidelberg N ------------------------------------------------------------------------------------ 6. Abstract Although extended jets from young stellar objects (YSOs) represent a rather dramatic demonstration of the outflow phenomenon common to pre-main sequence stars, statistically this phase is short-lived with respect to the classical T Tauri phase. Generally speaking, it is the more heavily extincted, or even embedded, T Tauri stars that display such jets. Recently however we have found evidence that the jet phenomenon may be much more universal than previously thought. A long-slit spectroscopic survey by us now strongly suggests that the high velocity forbidden emission lines seen in many classical T Tauri stars arise from arcsecond or subarcsecond scale jets. The nature of these jets, even their morphology, is however not known even though they are much more common than their extended counterparts. We propose here to carry out the first detailed study of this phenomenon, a task that can only be undertaken using HST. Our proposal concentrates on imaging certain T Tauri stars in the nearby Taurus Auriga Dark Cloud where, on the basis of ground- based observations and theory, one stands an excellent chance of resolving these jets with the PC of the WFPC2. Our targets have also been specially chosen to give us additional information on the evolution of jets in close binaries, a topic about which virtually nothing is known. ------------------------------------------------------------------------------------ 6759( 3) - 02/14/96 12:54 - [ 2] Observations Description ------------------------ YSO jets are only seen in line emission, most of which is of relatively low excitation, i.e. these jets emit most of their light in lines like [OI]Lambda6300 and [SII]LambdaLambda6716,6731. They can be distinguished from any associated reflection nebula by imaging in both line emission and nearby continuum filters. The continuum images can then be subtracted from the ``line+continuum'' frames to yield a ``pure'' emission line frame. We propose to apply this subtraction method by using the filters F631N ([OI]), F656N (HAlpha), and F673N ([SII]) as line filters, and the filters F569W and F791W as continuum filters. Because of its higher critical density, and because we expect electron densities N_e > 10^5 cm^-3 close to the source (i.e. less than about 0.3 arcsec), the [OI] line is particularly suited for imaging jets which can probably be traced close to the source. The [SII] filter is more appropriate for extended features (i.e. on scales greater than about 0.3 arcsec) or for cases where the central star is presumably occulted by a circumstellar disk, as suspected for FS Tau A and B on the basis of the HST images of HH30. The HAlpha images will be used in conjunction with the forbidden line images to measure excitation. It is hoped also that by imaging the jets in these different emission lines we will also seen evidence for differential cooling. Our targets (FS Tau, UZ Tau) are hierarchical TTS triple systems, where the third star is 20 arcsec and 4 arcsec from the close binary, which has a separation of about 0.3 arcsec for both objects. Thus in these cases our imaging is essentially confined to the PC. Our choice of exposure times and the number of orbits required are based on ground-based measurements of the jet fluxes. Typical integrated intensities of these jets per square arcsecond in HAlpha are 10^-15 ergs cm^-2 s^-1 arcsec^-2 with similar integrated intensities per square arcsecond in the other lines. UZ Tau will only be imaged in the [OI] 6300 line and in the continuum (using filter F569W), since its jet is 5 to 10 times fainter in the [SII] 6716,6731 lines and since in HAlpha imaging is not so suitable because of the strong stellar HAlpha emission component. In addition to two long exposures several short exposures in both the [OI] line and in the continuum will be necessary to avoid saturation of the sources and in order to trace the jet as close as possible to the source. Two orbits will be used for this part of the programme. The close binary FS Tau A and the classical jet source FS Tau B will be imaged simultaneously with PC and WFC, respectively. Since the sources are much fainter and extended due to strong reflection nebulae, saturation is far less a problem than with UZ Tau. The FS Tau region will be imaged in both HAlpha and [SII], and in F569W and F791W as continuum filters. Since the reflection nebulae are expected to have stong colour gradients (as observed in the HST images of HL Tau) imaging at two continuum wavelengths is necessary for a proper correction of the continuum contribution in the emission line filters. Three exposures in all four filters will be carried out for this region requiring a total of four orbits. Our targets have similar declinations so the visibility time is in all cases about 53 minutes. Real Time Justification ----------------------- No special requirements. No supporting observations. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 6759( 3) - 02/14/96 12:54 - [ 3] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 6759( 3) - 02/14/96 12:54 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 FS-TAU STAR,T TAURI RA=4H 22M 2.16S +/- 0.3",DEC=26D J2000 V = 14.58+/-0.40 STAR,WIND,JET,ISM,HERBI 57' 31.5" +/- 0.3",PLATE-ID=000L B-V = +1.37 G-HARO TYPE=M1 OBJECT,REFLECTION Comments: coordinates are from GSC; source is known to be variable in the range V = 14.1 - 17.6 mag; triple system: very close binary and a third star at a distance of 20 arcsec; Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) J1983.020 0.0 0.0 0.0 2 UZ-TAU STAR,T TAURI RA=4H 32M 42.96S +/- J2000 V = 12.86 STAR,WIND,JET,ISM,HERBI 0.3",DEC=25D 52' 31.8" +/- B-V = +1.19 G-HARO 0.3",PLATE-ID=000L TYPE=M3V OBJECT,REFLECTION Comments: coordinates are from GSC; source is known to be variable in the range V = 11.7 to 15.0 mag; triple system: very close binary and a third star at a distance of 4 arcsec; Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) J1983.020 0.0 0.0 0.0 6759( 3) - 02/14/96 12:54 - [ 5] Visit: 01 Visit Requirements: ORIENT 240D TO 285D On Hold Comments: Additional Comments: Description of position of target and possible orientation angles: The target should be placed at 10.7, 10.7 arcsec from the centre of the PC towards the apex of the 4 CCDs. The orientation angle for the U3 axis should be in the range from 240 to 285 degrees from north over east, OR from 95 to 110 degrees from north over east, OR from 140 to 155 degrees from north over east. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 FS-TAU WFPC2 IMAGE PC1-FIX F569W ATD-GAIN=15 1 100S POS TARG -10.7,-10.7 NO SPLIT MIN DUR MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 20 FS-TAU WFPC2 IMAGE PC1-FIX F569W ATD-GAIN=15 1 100S SAME POS AS 10 NO SPLIT MIN DUR MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 30 FS-TAU WFPC2 IMAGE PC1-FIX F569W ATD-GAIN=15 1 100S SAME POS AS 10 NO SPLIT MIN DUR MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 40 FS-TAU WFPC2 IMAGE PC1-FIX F791W ATD-GAIN=15 1 100S SAME POS AS 10 NO SPLIT MIN DUR MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 50 FS-TAU WFPC2 IMAGE PC1-FIX F791W ATD-GAIN=15 1 100S SAME POS AS 10 NO SPLIT MIN DUR MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 60 FS-TAU WFPC2 IMAGE PC1-FIX F791W ATD-GAIN=15 1 100S SAME POS AS 10 NO SPLIT MIN DUR MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 70 FS-TAU WFPC2 IMAGE PC1-FIX F656N CR-SPLIT=no,ATD 1 1200S SAME POS AS 10 NO SPLIT MIN DUR MAX DUR -GAIN=15 1500S ------------------------------------------------------------------------------------------------------------------------------------ 80 FS-TAU WFPC2 IMAGE PC1-FIX F656N CR-SPLIT=no,ATD 1 1200S SAME POS AS 10 NO SPLIT MIN DUR MAX DUR -GAIN=15 1500S ------------------------------------------------------------------------------------------------------------------------------------ 90 FS-TAU WFPC2 IMAGE PC1-FIX F656N CR-SPLIT=no,ATD 1 1200S SAME POS AS 10 NO SPLIT MIN DUR MAX DUR -GAIN=15 1500S ------------------------------------------------------------------------------------------------------------------------------------ 100 FS-TAU WFPC2 IMAGE PC1-FIX F673N CR-SPLIT=no,ATD 1 1200S SAME POS AS 10 NO SPLIT MIN DUR MAX DUR -GAIN=15 1500S ------------------------------------------------------------------------------------------------------------------------------------ 110 FS-TAU WFPC2 IMAGE PC1-FIX F673N CR-SPLIT=no,ATD 1 1200S SAME POS AS 10 NO SPLIT MIN DUR MAX DUR -GAIN=15 1500S ------------------------------------------------------------------------------------------------------------------------------------ 120 FS-TAU WFPC2 IMAGE PC1-FIX F673N CR-SPLIT=no,ATD 1 1200S SAME POS AS 10 NO SPLIT MIN DUR MAX DUR -GAIN=15 1500S ------------------------------------------------------------------------------------------------------------------------------------ 130 FS-TAU WFPC2 IMAGE PC1-FIX F673N CR-SPLIT=no,ATD 1 1200S SAME POS AS 10 NO SPLIT MIN DUR MAX DUR -GAIN=15 1500S ------------------------------------------------------------------------------------------------------------------------------------ 6759( 3) - 02/14/96 12:54 - [ 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 ------------------------------------------------------------------------------------------------------------------------------------ 10 UZ-TAU WFPC2 IMAGE PC1-FIX F569W ATD-GAIN=15 1 10S NO SPLIT MIN DUR MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 20 UZ-TAU WFPC2 IMAGE PC1-FIX F569W ATD-GAIN=15 1 10S SAME POS AS 10 NO SPLIT MIN DUR MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 30 UZ-TAU WFPC2 IMAGE PC1-FIX F569W ATD-GAIN=15 1 10S SAME POS AS 10 NO SPLIT MIN DUR MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 40 UZ-TAU WFPC2 IMAGE PC1-FIX F569W ATD-GAIN=15 1 10S SAME POS AS 10 NO SPLIT MIN DUR MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 50 UZ-TAU WFPC2 IMAGE PC1-FIX F569W ATD-GAIN=15 1 10S SAME POS AS 10 NO SPLIT MIN DUR MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 60 UZ-TAU WFPC2 IMAGE PC1-FIX F569W ATD-GAIN=15 1 30S SAME POS AS 10 NO SPLIT MIN DUR MAX DUR 40S ------------------------------------------------------------------------------------------------------------------------------------ 70 UZ-TAU WFPC2 IMAGE PC1-FIX F631N ATD-GAIN=15 1 300S SAME POS AS 10 NO SPLIT MIN DUR MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 80 UZ-TAU WFPC2 IMAGE PC1-FIX F631N ATD-GAIN=15 1 300S SAME POS AS 10 NO SPLIT MIN DUR MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 90 UZ-TAU WFPC2 IMAGE PC1-FIX F631N CR-SPLIT=no,ATD 1 900S SAME POS AS 10 END ORBIT NO SPLIT MIN DUR -GAIN=15 MAX DUR 1200S ------------------------------------------------------------------------------------------------------------------------------------ 200 UZ-TAU WFPC2 IMAGE PC1-FIX F569W ATD-GAIN=15 1 30S SAME POS AS 10 NO SPLIT MIN DUR MAX DUR 40S ------------------------------------------------------------------------------------------------------------------------------------ 210 UZ-TAU WFPC2 IMAGE PC1-FIX F569W ATD-GAIN=15 1 30S NO SPLIT MIN DUR MAX DUR 40S ------------------------------------------------------------------------------------------------------------------------------------ 220 UZ-TAU WFPC2 IMAGE PC1-FIX F569W ATD-GAIN=15 1 30S SAME POS AS 10 NO SPLIT MIN DUR MAX DUR 40S ------------------------------------------------------------------------------------------------------------------------------------ 230 UZ-TAU WFPC2 IMAGE PC1-FIX F569W ATD-GAIN=15 1 30S SAME POS AS 10 NO SPLIT MIN DUR MAX DUR 40S ------------------------------------------------------------------------------------------------------------------------------------ 240 UZ-TAU WFPC2 IMAGE PC1-FIX F569W ATD-GAIN=15 1 30S SAME POS AS 10 NO SPLIT MIN DUR MAX DUR 40S ------------------------------------------------------------------------------------------------------------------------------------ 250 UZ-TAU WFPC2 IMAGE PC1-FIX F569W ATD-GAIN=15 1 30S SAME POS AS 10 NO SPLIT MIN DUR MAX DUR 40S ------------------------------------------------------------------------------------------------------------------------------------ 260 UZ-TAU WFPC2 IMAGE PC1-FIX F631N ATD-GAIN=15 1 300S SAME POS AS 10 NO SPLIT MIN DUR MAX DUR ------------------------------------------------------------------------------------------------------------------------------------ 270 UZ-TAU WFPC2 IMAGE PC1-FIX F631N ATD-GAIN=15 1 300S SAME POS AS 10 MAX DUR NO SPLIT MIN DUR ------------------------------------------------------------------------------------------------------------------------------------ 280 UZ-TAU WFPC2 IMAGE PC1-FIX F631N CR-SPLIT=no,ATD 1 900S SAME POS AS 10 END ORBIT NO SPLIT MIN DUR -GAIN=15 MAX DUR 1200S ------------------------------------------------------------------------------------------------------------------------------------ 6759( 3) - 02/14/96 12:54 - [ 7] Summary Form for Proposal 6759 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ATD-GAIN=15 CR-SPLIT=no ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category BINARIES AND STAR FORMATION ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 240D TO 285D POS TARG -10.7,-10.7 NO SPLIT MIN DUR MAX DUR SAME POS AS 10 NO SPLIT MIN DUR MAX DUR SAME POS AS 10 NO SPLIT MIN DUR MAX DUR 1500S SAME POS AS 10 NO SPLIT MIN DUR MAX DUR 40S SAME POS AS 10 END ORBIT NO SPLIT MIN DUR MAX DUR 1200S SAME POS AS 10 MAX DUR NO SPLIT MIN DUR ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F569W F791W F656N F673N F631N ------------------------------------------------------------------------------------------------------------------------------------ Target Names FS-TAU UZ-TAU ------------------------------------------------------------------------------------------------------------------------------------