!__Proposal-Section__ !6132 ! Hubble Space Telescope Cycle 5 (1995) Phase II Proposal Template ! $Id: 6132,v 15.1 1995/11/21 19:26:37 pepsa Exp $ ! ! Refer to the HST Phase II Proposal Instructions to fill this out ! ! Anything after a "!" is ignored, and may be deleted ! ! All keywords with multiple entries are comma delimited except the ! Visit_Requirements and Special_Requirements keywords which can be ! delimited with carriage returns or semi-colons, but not commas ! ! For help call your Program Coordinator: Christian Ready ! Phone: 410 338-4546 , E-mail: ready@stsci.edu ! ! This partially completed template was generated from a Phase I proposal. ! Date generated: Mon Dec 19 08:37:01 EST 1994 ! Proposal_Information ! Section 4 Title: Envelopes and jets of young stellar objects Proposal_Category: GO Scientific_Category: Interstellar Medium Cycle: 5 Investigators PI_name: Scott J. Kenyon PI_Institution: Smithsonian Astrophysical Observatory CoI_Name: Lee Hartmann CoI_Institution: Smithsonian Astrophysical Observatory Contact: ! Y or N (designate at most one contact) CoI_Name: Barbara Whitney CoI_Institution: Smithsonian Astrophysical Observatory Contact: ! Y or N (designate at most one contact) CoI_Name: Stephen Strom CoI_Institution: Five College Astronomy Department Contact: ! Y or N (designate at most one contact) CoI_Name: Suzan Edwards CoI_Institution: Five College Astronomy Department Contact: ! Y or N (designate at most one contact) CoI_Name: Nuria Calvet CoI_Institution: Centro de Investigaciones de Astronomia Contact: ! Y or N (designate at most one contact) CoI_Name: Deborah Padgett CoI_Institution: Infrared Processing and Analysis Center Contact: ! Y or N (designate at most one contact) Abstract: ! Free format text (please update) We propose an imaging program to constrain the initial angular momentum of protostellar cloud cores, the radii of circumstellar disks, and the interaction between the highly- collimated jets and protostellar envelopes of young stellar objects. Our sample spans a range of evolutionary states, from the youngest stars still enshrouded in their parent clouds to older systems where infall has nearly ceased. PC images in an I-band continuum filter will constrain the structure of dusty envelopes outlined in scattered light; S II images will determine the location of the jet relative to the infalling envelope. Our scattering models for ground-based images suggest that optically thick protostellar envelopes have bipolar cavities that allow light from the central star to illuminate a large reflection nebula. HST images will enable us to measure the size and shape of this cavity close to the central star and its surrounding disk. By comparing the degree of jet collimation and the shape of the scattered light cavity on 0sec point1--0sec point2 scales, we will also explore the possibility that jets create the cavities, shape the scattered light nebulae, reverse the infall, and set the final mass of the star. Theoretical models predict that scattered light can be enhanced in a rotating ring, where material from the envelope lands on the outer disk. Detection of these rings in the least-reddened sources of our sample would provide direct measurements of the disk radius and indirect measurements of the initial angular momentum per unit mass in the parent clouds. Questions ! Free format text (please update) Observing_Description: We request PC observations of 4 embedded protostars and 6 T Tauri stars (TTS) in the Taurus dark cloud. The protostars are the brightest and bluest known. We have previously modeled their SEDs and near-IR images; some have strong S II emission (Kenyon Etal 1993a, b; see Figures 1--2). The TTS are also bright and have K--N colors intermediate between those of pure disk sources and protostars. Our plan is to acquire 1100 sec exposures of each protostar with the F814W (2 images) and F673N filters (2 images). The F814W filter is the one of the longest wavelength filters available on HST and gives us the best S/N for very red sources. We predict S/N ~ 15--20 per resolution element per 1100 sec continuum exposure for a monochromatic source with an I magnitude equal to that of a typical protostar with an angular size of 15". We detected S II emission in several protostars at count rates of 0.05 counts per sec per pixel with a 48" telescope. If this emission is confined to an unresolved jet with a length of several arcsec, we expect S/N ~ 7--10 per resolution element per 1100 sec exposure in the jet. Most TTS have F(O I) ~ 2--3F(S II). We chose S II for this program, because the differential reddening between O I and S II for a typical protostar is at least 1.5 mag. This portion of our program requires 8 orbits. We also plan observations of 6 TTS with the same filter set. The TTS exposure times are short: 0.1--5 sec at I and 10--300 sec at S II will saturate the central pixel. Our first goal is to acquire three I-band exposures that almost saturate the central pixel and a fourth image overexposed by a factor of ~ 10. We will subtract a normalized PSF from a coadd of the three short exposures and analyze the residual flux. Simulations indicate that any flux from a flared disk or envelope will be ~ 5--10 times brighter than the stellar PSF at 0sec point5. This flux level corresponds to S/N ~ 10 per resolution element per exposure above the read noise. Our second goal is to acquire S II images that just saturate the central pixel. The program TTS have EW(S II) = 0.2--2 Angstrom, which implies S/N ~ 5--15 per resolution element per exposure for an unresolved jet 1" in length. We expect to acquire 4--8 S II images per source, depending on the integration time, and can bin the data to increase S/N for weak sources. This portion of our program requires 6 orbits. We plan to devote one orbit to measuring the PSF of a single main sequence star in the S II silter to make sure we have the best possible PSF to subtract from our program S II images. Real_Time_Justification: We will acquire several types of supporting observations. 1. Near-IR imaging polarimetry of protostars and TTS with COB at the KPNO 1.3-m telescope (Dec 1994). Imaging polarimetry with 1" resolution will constrain the shape and orientation of the outflow cavity on 5--15" scales. 2. Narrow-band optical imaging of protostars with the SAO 48 telescope (Nov -Dec 1994). These images will constrain frequency of S II emission in protostars. 3. VRI optical imaging of protostars and TTS with the SAO 48 telescope (Nov-Dec 1994). These images will constrain the shape of the outflow cavity on 5-- 15" scales. Calibration_Justification: ! Move appropriate text from Real_Time_Justification Additional_Comments: Fixed_Targets ! Section 5.1 Target_Number: 1 Target_Name: IRAS04016+2610 Alternate_Names: Description: STAR, T Tauri Star, Protoplanetary Disk, Jet Position: RA=04H 04M 43.09S +/- 2.0S, DEC=26D 18' 58.0" +/- 2.0" Equinox: J2000.0 Flux: V=20.5 Target_Number: 2 Target_Name: IRAS04248+2612 Alternate_Names: Description: STAR, T Tauri Star, Protoplanetary Disk, Jet Position: RA=04H 27M 57.69S +/- 2.0S, DEC=26D 19' 19.0" +/- 2.0" Equinox: J2000.0 Flux: V=22.0 Target_Number: 3 Target_Name: IRAS04303+2247 Alternate_Names: Description: STAR, T Tauri Star, Protoplanetary Disk, Jet Position: RA=04H 33M 16.20S +/- 2.0S, DEC=22D 53' 20.4" +/- 2.0" Equinox: J2000.0 Flux: V=22.5 Target_Number: 4 Target_Name: CW-TAU Alternate_Names: Description: STAR, T Tauri Star, Protoplanetary Disk, Jet Position: RA=04H 14M 17.77S +/- 1.0S, DEC=28D 10' 29.0" +/- 1.0" Equinox: J2000.0 Flux: V=13.3 ! This is a template for a single visit containing a single exposure ! Repeat exposure and visit blocks as needed Visits ! Section 6 Visit_Number: 1 Visit_Requirements: ! Section 7.1 ! Uncomment or copy visit level special requirements needed ! Most of these requirements (including ORIENT) will limit scheduling ! PCS MODE [Fine | Gyro] ! GUIDing TOLerance ! ORIENTation TO ! ORIENTation TO FROM ! ORIENTation TO FROM NOMINAL ! SAME ORIENTation AS ! CVZ ! PARallel ! AFTER [BY [TO ]] ! AFTER ! BEFORE ! BETWEEN AND ! GROUP WITHIN