8120( 13) - 04/24/00 11:23 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 8120 Version: 13 Check-in Date: 24-Apr-2000 11:22:24 1.Proposal Title: Determination of Circumstellar Cloud Mass Loss Rates with STIS Spectra ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 8 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: C. O'Dell Rice University CoI: Dr. W. J. Henney Instituto de Astronom N CoI: Prof. John Meaburn Manchester University N ------------------------------------------------------------------------------------ 5. Abstract We propose to resolve the question of whether or not the circumstellar disks around young low mass stars in clusters containing O type stars are rapidly destroyed by photoevaporation. The answer will determine whether or not the conditions necessary for planet formation are common or rare in the massive star clusters where most stars are created. At the present there is a conundrum arising from the fact that most of the circumstellar disks survive in the Orion Nebula Cluster even though the theoretical models predict that the intense radiation field should have destroyed them in times short compared with the estimated age of the cluster. We propose to obtain STIS high resolution spectra which will allow direct measurement of any photoevaporative flow off disks around two young low mass stars near \tc\ Ori. These results will test existing theories for photoevaporation and directly tell us how long these disks can survive. Only the HST and STIS have the right combination o f spatial and spectral resolution to adequately reject the contaminating light from the Orion Nebula itself and allow clear determination of the emission coming from the young stellar object. ------------------------------------------------------------------------------------ 8120( 13) - 04/24/00 11:23 - [ 2] Observations Description ------------------------ Only the FUV MAMA configuration of STIS offers the necessary spectral resolution for this program, producing a resolution of about 2.5 kms. This is adequate for detecting the photoevaporative expansions of about 12--20 kms\ and distinquishing them from the thermal broadening, which will be about 6 kms. Fortunately, the C III doublet near 1908 Angstrom\ is sufficiently strong (about 10\ observations) to give good S/N ratios in acceptable exposure times. This doublet has the added advantage of being a density indicator. In the inner parts of the proplyd atmospheres the semi- forbidden C III 1909 line will dominate and in the outer parts of the atmospheres the forbidden C III 1907 line will reach about 0.3 of the 1909 line's intensity. The wavelength separation of 2.05Angstrom\ corresponds to a velocity separation of 322 kms, so that the lines will be adequately split. We will use the 6x0.2"\ slit, which will sample the diagnostically most important portion of the proplyds b y its width and the the long slit will allow determination of the adjacent nebular background. The resulting spectrum will be complex because of the overlap of orders, but since there are few strong emission lines the challenge will be to remove the signatures of the scattered light stellar spectrum coming from the dust in the nebula. At this high resolution the continuum will be very weak. The slit orientation will be selected to be along a line from the central star of the proplyd to the photoionizing star \tc\ Ori. One full (unocculted portion) orbit will be necessary for obtaining a spectrum with a signal to noise ratio of 50 on Ori 167--317, which has an H Alpha\ flux of 3.1 photons cm^-2 s^-1 and two orbits for Ori 158--323, with a flux of 1.41 photons cm^-2 s^-1. The two objects were selected because they are not only among the brightess proplyds, they also have simple appearances and their expected geometries should yield to comparison with the theoretical models. Th e parallel observations with WFPC2 will employ the same set of filters used for building up the initial mosaic image that provided the complete survey of proplyds in the Orion Nebula. The pointing of the WFPC2 is determined by the position angle and location of the primary target proplyds. Fortunately these are interesting locations that have not been imaged before by HST and will slightly overlap the existing mosaic, so that the new parallel observations will extend the homogeneous census of this star formation region. Ground based images indicate that there is one new HH object in one of the proposed parallel WFPC2 fields of view. A general argument for extending the mosaic is shown in recent results obtained as parallel observations (GO 6603) in the northern part of the nebula where one new HH object was found at the extension of the Allen and Burton H_2 fingers and an additional edge-on dark disk proplyd was discovered. The analysis techniques employed will be similar to those employed by our team on groundbased echelle spectra. Both team members Meaburn and O'Dell have extensive experience with similar data, Meaburn with the Manchester spectrograph which has been used for high spectral resolution studies of numerous H II regions and O'Dell with the Coude Feed system at KPNO, where he and his students have mapped the internal velocities of the Orion Nebula at high spectral, but low spatial resolution. Both observers have intentionally included proplyds in their studies, with Meaburn publishing a detailed analysis in the cited Henney et al.\ (1997) paper. O'Dell's most detailed study is being done at the present with Keck HIRES spectra obtained last December, a sample of which is included as Figure 1b. Henney is a product of the Manchester department which has traditionally specialized in the dynamics of ionized gas and has calculated sophisticated predictive models of the proplyds and published a comparison of the predicted and observed sp ec tra. This combination of observational and theoretical experience should lead to rapid and correct analysis of the new STIS spectra. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 8120( 13) - 04/24/00 11:23 - [ 3] Data Distribution Paper Products: YES Media: ELECTRONIC Blocking Factor: 10 Ship To: PI_Address Ship Via: Email: ------------------------------------------------------------------------------------ 8120( 13) - 04/24/00 11:23 - [ 4] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC1976- STAR, B0-B2 V-IV RA=5H 35M 15.81S +/- 0.010S, J2000 V = 20.0 OFFSET12 DEC=-5D 23' 14.1" +/- 0.15" B-V = 0.0 TYPE=B0.5V V = 6.72+/-0.05 E(B-V) = 0.28 Coordinate Source: Comments: POSSIBLE, BUT UNLIKELY, V = 7.7 BECAUSE STAR ECLIPSING BINARY P=65.432D, PRIMARY ECLIPSE LASTS 20H WITH 2.5H CONSTANT MINIMUM AT MID-ECLIPSE. S&T 4/95 p.75 - min. light predicted ~4:48 UT April 11, 1995 7 hrs to fade & 7 hrs to recover. 2 NGC1976-167- ISM, HII REGION, STAR, RA-OFF=+0.934S+/- 0.001S, DEC- 2000 SURF-CONT(5470)=4.00e-14 317 T TAURI STAR OFF=-2.14"+/- 0.01", FROM 1 V = 10.0+/-0.05 Coordinate Source: Comments: Position corrected to keep end of slit 5" from theta1c ori. 52 NGC1976-167- ISM, HII REGION, STAR, RA-OFF=+0.965S+/- 0.001S, DEC- 2000 SURF-CONT(5470)=4.00e-14 317A T TAURI STAR OFF=-1.46"+/- 0.01", FROM 1 V = 10.0+/-0.05 Coordinate Source: Comments: Position corrected to keep end of slit 5.82" from theta1c ori. 8120( 13) - 04/24/00 11:23 - [ 5] Visit: 01 Visit Priority: Visit Requirements: ORIENT 257D to 261D On Hold Comments: Additional Comments: ORIENT tightened because of displacing the slit center. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 NGC1976-OFF STIS/C ACQ F25ND3 MIRROR ACQTYPE=POINT 1 0.1 S ONBOARD ACQ FOR 21 SET12 CD through 101 Comments: Acquisition exposure on Theta1A Ori. ------------------------------------------------------------------------------------------------------------------------------------ 21 NGC1976-167 STIS/N ACCUM 6X0.2 E230H 1913 CR-SPLIT=NO 1 700.0 S PAR 22 WITH 21 -317 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 22 NGC1976-167 WFPC2 IMAGE WFALL F547M 5476 CR-SPlIT=NO 3 100 S -317 Comments: Coordinated Parallel with 21 ------------------------------------------------------------------------------------------------------------------------------------ 31 NGC1976-167 STIS/N ACCUM 6X0.2 E230H 1913 CR-SPLIT=NO 1 700.0 S PAR 32 WITH 31 -317 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 32 NGC1976-167 WFPC2 IMAGE PC1 F656N 6563 CR-SPLIT=NO 1 350 S -317 Comments: Coordinated Parallel with 31 ------------------------------------------------------------------------------------------------------------------------------------ 41 NGC1976-167 STIS/N ACCUM 6X0.2 E230H 1913 CR-SPLIT=NO 1 650.0 S PAR 42 WITH 41 -317 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 42 NGC1976-167 WFPC2 IMAGE PC1 F656N 6563 CR-SPLIT=NO 1 350 S -317 Comments: Coordinated Parallel with 41 ------------------------------------------------------------------------------------------------------------------------------------ 51 NGC1976-167 STIS/N ACCUM 6X0.2 E230H 1913 CR-SPLIT=NO 1 900.0 S PAR 52 WITH 51 -317 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 52 NGC1976-167 WFPC2 IMAGE PC1 F658N CR-SPLIT=NO 1 600 S -317 Comments: Coordinated Parallel with 51 ------------------------------------------------------------------------------------------------------------------------------------ 61 NGC1976-167 STIS/N ACCUM 6X0.2 E230H 1913 CR-SPLIT=NO 1 900.0 S PAR 62 WITH 61 -317 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 62 NGC1976-167 WFPC2 IMAGE PC1 F658N CR-SPLIT=NO 1 550 S -317 Comments: Coordinated Parallel with 61 ------------------------------------------------------------------------------------------------------------------------------------ 8120( 13) - 04/24/00 11:23 - [ 6] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 71 NGC1976-167 STIS/N ACCUM 6X0.2 E230H 1913 CR-SPLIT=NO 1 800.0 S PAR 72 WITH 71 -317 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 72 NGC1976-167 WFPC2 IMAGE PC1 F502N CR-SPLIT=NO 1 550 S -317 Comments: Coordinated Parallel with 71 ------------------------------------------------------------------------------------------------------------------------------------ 81 NGC1976-167 STIS/N ACCUM 6X0.2 E230H 1913 CR-SPLIT=NO 1 850.0 S PAR 82 WITH 81 -317 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 82 NGC1976-167 WFPC2 IMAGE PC1 F502N CR-SPLIT=NO 1 600 S -317 Comments: Coordinated Parallel with 81 ------------------------------------------------------------------------------------------------------------------------------------ 91 NGC1976-167 STIS/N ACCUM 6X0.2 E230H 1913 CR-SPLIT=NO 1 850.0 S PAR 92 WITH 91 -317 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 92 NGC1976-167 WFPC2 IMAGE PC1 F673N CR-SPLIT=NO 1 550 S -317 Comments: Coordinated Parallel with 91 ------------------------------------------------------------------------------------------------------------------------------------ 101 NGC1976-167 STIS/N ACCUM 6X0.2 E230H 1913 CR-SPLIT=NO 1 850.0 S PAR 102 WITH 101 -317 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 102 NGC1976-167 WFPC2 IMAGE PC1 F673N CR-SPLIT=NO 1 550 S -317 Comments: Coordinated Parallel with 101 ------------------------------------------------------------------------------------------------------------------------------------ 8120( 13) - 04/24/00 11:23 - [ 7] Visit: 51 Visit Priority: Visit Requirements: ORIENT 257D to 261D On Hold Comments: Additional Comments: ORIENT tightened because of displacing the slit center. Visit 51 MUST USE a previously proven pair: Pair 0477400829F30477400885F1 OK'd for use Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 NGC1976-OFF STIS/C ACQ F25ND3 MIRROR ACQTYPE=POINT 1 0.1 S SET12 CD Comments: Acquisition exposure on Theta1A Ori. ------------------------------------------------------------------------------------------------------------------------------------ 15 NGC1976-OFF STIS/C ACQ/PEA 0.3X0.0 MIRROR 1 0.8 S SET12 CD K 5ND Comments: Acq/peak exposure on Theta1A Ori ------------------------------------------------------------------------------------------------------------------------------------ 21 NGC1976-167 STIS/N ACCUM 6X0.2 E230H 1913 1 300.0 S PAR 22 WITH 21 -317A UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 22 NGC1976-167 WFPC2 IMAGE WFALL F547M 5476 CR-SPlIT=NO 2 60 S -317A Comments: Coordinated Parallel with 21 ------------------------------------------------------------------------------------------------------------------------------------ 31 NGC1976-167 STIS/N ACCUM 6X0.2 E230H 1913 1 600.0 S PAR 32 WITH 31 -317A UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 32 NGC1976-167 WFPC2 IMAGE PC1 F656N 6563 CR-SPLIT=NO 1 250 S -317A Comments: Coordinated Parallel with 31 ------------------------------------------------------------------------------------------------------------------------------------ 41 NGC1976-167 STIS/N ACCUM 6X0.2 E230H 1913 1 650.0 S PAR 42 WITH 41 -317A UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 42 NGC1976-167 WFPC2 IMAGE PC1 F656N 6563 CR-SPLIT=NO 1 350 S -317A Comments: Coordinated Parallel with 41 ------------------------------------------------------------------------------------------------------------------------------------ 51 NGC1976-167 STIS/N ACCUM 6X0.2 E230H 1913 1 900.0 S PAR 52 WITH 51 -317A UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 52 NGC1976-167 WFPC2 IMAGE PC1 F658N CR-SPLIT=NO 1 600 S -317A Comments: Coordinated Parallel with 51 ------------------------------------------------------------------------------------------------------------------------------------ 61 NGC1976-167 STIS/N ACCUM 6X0.2 E230H 1913 1 900.0 S PAR 62 WITH 61 -317A UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 8120( 13) - 04/24/00 11:23 - [ 8] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 62 NGC1976-167 WFPC2 IMAGE PC1 F658N CR-SPLIT=NO 1 550 S -317A Comments: Coordinated Parallel with 61 ------------------------------------------------------------------------------------------------------------------------------------ 71 NGC1976-167 STIS/N ACCUM 6X0.2 E230H 1913 1 800.0 S PAR 72 WITH 71 -317A UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 72 NGC1976-167 WFPC2 IMAGE PC1 F502N CR-SPLIT=NO 1 550 S -317A Comments: Coordinated Parallel with 71 ------------------------------------------------------------------------------------------------------------------------------------ 81 NGC1976-167 STIS/N ACCUM 6X0.2 E230H 1913 1 850.0 S PAR 82 WITH 81 -317A UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 82 NGC1976-167 WFPC2 IMAGE PC1 F502N CR-SPLIT=NO 1 600 S -317A Comments: Coordinated Parallel with 81 ------------------------------------------------------------------------------------------------------------------------------------ 91 NGC1976-167 STIS/N ACCUM 6X0.2 E230H 1913 1 850.0 S PAR 92 WITH 91 -317A UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 92 NGC1976-167 WFPC2 IMAGE PC1 F673N CR-SPLIT=NO 1 550 S -317A Comments: Coordinated Parallel with 91 ------------------------------------------------------------------------------------------------------------------------------------ 101 NGC1976-167 STIS/N ACCUM 6X0.2 E230H 1913 1 850.0 S PAR 102 WITH 101 -317A UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 102 NGC1976-167 WFPC2 IMAGE PC1 F673N CR-SPLIT=NO 1 550 S -317A Comments: Coordinated Parallel with 101 ------------------------------------------------------------------------------------------------------------------------------------ 8120( 13) - 04/24/00 11:23 - [ 9] Summary Form for Proposal 8120 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F25ND3 6X0.2 WFALL PC1 0.3X0.05ND ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD STIS/NUV-MAMA WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM IMAGE ACQ/PEAK ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT CR-SPLIT=NO CR-SPlIT=NO ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 257D to 261D ONBOARD ACQ FOR 21 through 101 PAR 22 WITH 21 PAR 32 WITH 31 PAR 42 WITH 41 PAR 52 WITH 51 PAR 62 WITH 61 PAR 72 WITH 71 PAR 82 WITH 81 PAR 92 WITH 91 PAR 102 WITH 101 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR E230H F547M F656N F658N F502N F673N ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC1976-OFFSET12 NGC1976-167-317 NGC1976-167-317A ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 1913 5476 6563 ------------------------------------------------------------------------------------------------------------------------------------