6134( 28) - 02/22/96 12:55 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6134 Version: 28 Check-in Date: 22-Feb-1996 12:47:04 1.Proposal Title: Investigating the Nature of Circumstellar Material in Young Clusters ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Interstellar Medium GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Elizabeth Lada University of Maryland CoI: Lee Mundy Univ. of Maryland N CoI: Edward Shaya Univ. of Maryland N CoI: John Stauffer Smithsonian Astrophyical Obs. N ------------------------------------------------------------------------------------ 6. Abstract Recent studies of circumstellar nebulae associated with young stars in the Trapezium have illustrated the power of using HST to investigate the circumstellar environments of young stars in clusters. We propose to use WFPC2 to obtain sensitive broad band images of a sample of 4 young clusters associated with bright reflection nebulae. The primary goal of these observations is to search for evidence of circumstellar material around the young cluster members by looking for this material in 1.) absorption against the reflection nebulosity, 2.) in the reflected light of the cluster B star and 3.) in the reflected light of the young cluster stars themselves. The proposed HST data will be used in combination with near infrared and millimeter wavelength data to determine 1.) the frequency distribution of circumstellar material and disks in undisturbed young cluster environments, 2.) the size and mass distributions of circumstellar nebulae in clusters, and 3.) the correlation of such properties with stellar luminosity. Finally comparison of the results for the 5 clusters will allow us to explore the relative timescales for circumstellar evolution in young cluster stars and possibly constrain the timescales for planet formation in a cluster environment. ------------------------------------------------------------------------------------ 6134( 28) - 02/22/96 12:55 - [ 2] Observations Description ------------------------ This project requires the acquisition of images with a broad range of exposure times. Since the brightest stars in the target clusters are M_V ~ 9 while the characteristic surface brightnesses of the large-scale nebulae are in the range from 19.5 to 20.5 mag per arcsec^2, it is not possible to image the broad nebulosity without saturating the brighter cluster stars. The observations will be made toward a number of carefully selected positions in each cluster. These positions will be chosen to avoid the very brightest cluster stars (to minimize bleeding, diffraction spikes, and scattered light) yet to maximize the brightness of the extended reflection nebulosity and the concentration of young cluster stars. We have acquired, or will be acquiring, optical CCD, and near infrared images to assist in the selection of target positions. All the clusters were selected to be in regions where the contribution of background stars is minimized. This is an exploratory project in which we will utilize two different observing strategies. For one of our targets, we will acquire 0.4 second, 4 second and 40 second CR splits in the `Wide V' (F555W), and `Wide R' (F702W) filters. With these exposure times, stars dimmer approximately 16, 14 and 11 magnitudes will be unsaturated in the WF and can be compared with the point spread function to search extended emission. By comparing the color of the emission in the `Wide V' and `Wide R' filters we can calculate the color of marginally extended emission to confirm it is reflected light. In order to accomplish the goal of searching for circumstellar material in absorption against the extended nebulae and in reflected B-star light, we acquire deep integrations in the `Wide V' and `Wide R' filters. An average region in the general reflection nebulae has a surface brightness of 21 mag per arcsec^2 or 26 mag per pixel in the WF camera. For a total integration time of 1200 seconds (taken as three 400 second CR splits in spatial scan mode (3 dwell points)), we expect to obtain a final S/N ratio of 10. This calculation is based on a read noise of 5 electrons per pixel, an integration time of 200 seconds per sub- image and an average sky brightness of 22.5 mag per square arcsecond. Detections levels in this range are needed to reasonably image the absorption or emission shapes. The above observations for 2 fields in IC348 can be done in 4 orbits. Due to time constraints, a second less complete observing strategy will be used to sample 3 additional clusters in the remaining 4 orbits. In these clusters, we will obtain a 1200 sec integration in the `Wide V' filter, this time taken as two 600 sec CR splits in scan mode (2 dwell points). We also take a 40 sec CR split in the `Wide V' filter and a 200 sec CR split in the `Wide R'. The deep exposure will be used to search for absorption against background reflection nebulosity and for faint reflection nebulosity from any circumstellar material. The shorter `Wide V' observation is needed to search for reflection nebulosity around brighter stars that may be saturated in the longer exposures. The intermediate integrations in the `Wide R' will enable us to obtain colors for many of our target sources. The point of this second strategy is to enable us to search for circumstellar material in a number of clusters covering a range of ages and cluster environments. Nebula D WF Pixel B Star Max. S.B. (pc) (AU) M_V (mag/arcsec^2) NGC 1333 400 40 10.5 20.4 IC 348 350 35 8.5 20.1 NGC 2071 400 40 10.1 20.2 NGC 2068 400 40 10.6 19.5 Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 6134( 28) - 02/22/96 12:55 - [ 3] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 6134( 28) - 02/22/96 12:55 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 IC348 STELLAR CLUSTER RA=3H 44M 34.421S +/- 0.1S, J2000 SURF(V) = 21+/-1 DEC=32D 09' 43.89" +/- 1" 2 NGC2068 STELLAR CLUSTER RA=5H 46M 45.99S +/- 0.1S, J2000 SURF(V) = 21+/-1 DEC=00D 04' 00.04" +/- 1" 3 NGC2071 STELLAR CLUSTER RA=5H 47M 07.86S +/- 0.1S, J2000 SURF(V) = 21+/-1 DEC=00D 17' 55.85" +/- 1" 4 NGC1333- STELLAR CLUSTER RA=3H 29M 19.770S +/- 0.1S, J2000 SURF(V) = 21+/-1 NORTH DEC=31D 24' 49.98" +/- 1" Comments: Northern bright star of NGC1333 field. 5 NGC1333- STELLAR CLUSTER RA=3H 29M 10.443S +/- 0.1S, J2000 SURF(V) = 21+/-1 SOUTH DEC=31D 21' 58.74" +/- 1" Comments: Southern bright star of NGC1333 field. 6134( 28) - 02/22/96 12:55 - [ 5] Visit: 01 Visit Requirements: ORIENTation 80D TO 100D On Hold Comments: Additional Comments: Schedulers' note: Please leave some time (1-3 hours) after execution of this visit. The WFPC chips are really gonna get blasted by this bright target. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 IC348 WFPC2 IMAGE PC1-FIX F555W ATD-GAIN=7,CR- 1 0.4S SPLIT=DEF ------------------------------------------------------------------------------------------------------------------------------------ 2 IC348 WFPC2 IMAGE PC1-FIX F702W ATD-GAIN=7,CR- 1 0.4S SPLIT=DEF ------------------------------------------------------------------------------------------------------------------------------------ 3 IC348 WFPC2 IMAGE PC1-FIX F702W ATD-GAIN=7,CR- 1 4.00S SPLIT=DEF ------------------------------------------------------------------------------------------------------------------------------------ 4 IC348 WFPC2 IMAGE PC1-FIX F555W ATD-GAIN=7,CR- 1 4.00S SPLIT=DEF ------------------------------------------------------------------------------------------------------------------------------------ 5 IC348 WFPC2 IMAGE PC1-FIX F555W ATD-GAIN=7,CR- 1 40.0S SPLIT=DEF ------------------------------------------------------------------------------------------------------------------------------------ 6 IC348 WFPC2 IMAGE PC1-FIX F702W ATD-GAIN=7,CR- 1 40.0S SPLIT=DEF ------------------------------------------------------------------------------------------------------------------------------------ 7 IC348 WFPC2 IMAGE PC1-FIX F702W ATD-GAIN=7,CR- 1 400.00S SPATIAL SCAN 1 SPLIT=DEF,SCAN- READ=ALL,CLOCKS =YES ------------------------------------------------------------------------------------------------------------------------------------ 8 IC348 WFPC2 IMAGE PC1-FIX F555W ATD-GAIN=7,CR- 1 400.00S SPATIAL SCAN 1 SPLIT=DEF,SCAN- READ=ALL,CLOCKS =YES ------------------------------------------------------------------------------------------------------------------------------------ 6134( 28) - 02/22/96 12:55 - [ 6] Visit: 02 Visit Requirements: ORIENTation 260D to 280D On Hold Comments: Additional Comments: Same as Visit 01 but this time 180D away from Visit 01 Schedulers' note: Please leave some time (1-3 hours) after execution of this visit. The WFPC chips are really gonna get blasted by this bright target. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 IC348 WFPC2 IMAGE PC1-FIX F555W ATD-GAIN=7,CR- 1 0.4S SPLIT=DEF ------------------------------------------------------------------------------------------------------------------------------------ 2 IC348 WFPC2 IMAGE PC1-FIX F702W ATD-GAIN=7,CR- 1 0.4S SPLIT=DEF ------------------------------------------------------------------------------------------------------------------------------------ 3 IC348 WFPC2 IMAGE PC1-FIX F702W ATD-GAIN=7,CR- 1 4.00S SPLIT=DEF ------------------------------------------------------------------------------------------------------------------------------------ 4 IC348 WFPC2 IMAGE PC1-FIX F555W ATD-GAIN=7,CR- 1 4.00S SPLIT=DEF ------------------------------------------------------------------------------------------------------------------------------------ 5 IC348 WFPC2 IMAGE PC1-FIX F555W ATD-GAIN=7,CR- 1 40.0S SPLIT=DEF ------------------------------------------------------------------------------------------------------------------------------------ 6 IC348 WFPC2 IMAGE PC1-FIX F702W ATD-GAIN=7,CR- 1 40.0S SPLIT=DEF ------------------------------------------------------------------------------------------------------------------------------------ 7 IC348 WFPC2 IMAGE PC1-FIX F702W ATD-GAIN=7,CR- 1 400.00S SPATIAL SCAN 1 SPLIT=DEF,SCAN- READ=ALL,CLOCKS =YES ------------------------------------------------------------------------------------------------------------------------------------ 8 IC348 WFPC2 IMAGE PC1-FIX F555W ATD-GAIN=7,CR- 1 400.00S SPATIAL SCAN 1 SPLIT=DEF,SCAN- READ=ALL,CLOCKS =YES ------------------------------------------------------------------------------------------------------------------------------------ 6134( 28) - 02/22/96 12:55 - [ 7] Visit: 03 Visit Requirements: On Hold Comments: Additional Comments: Schedulers' note: Please leave some time (1-3 hours) after execution of this visit. The WFPC chips are really gonna get blasted by this bright target. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC2068 WFPC2 IMAGE PC1-FIX F555W ATD-GAIN=7,CR- 1 40.0S SPLIT=DEF ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC2068 WFPC2 IMAGE PC1-FIX F702W ATD-GAIN=7,CR- 1 200.00S SPLIT=DEF,CLOCK S=YES ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC2068 WFPC2 IMAGE PC1-FIX F555W ATD-GAIN=7,CR- 1 600.00S SPATIAL SCAN 2 SPLIT=DEF,SCAN- READ=ALL,CLOCKS =YES ------------------------------------------------------------------------------------------------------------------------------------ 6134( 28) - 02/22/96 12:55 - [ 8] Visit: 04 Visit Requirements: On Hold Comments: Additional Comments: Schedulers' note: Please leave some time (1-3 hours) after execution of this visit. The WFPC chips are really gonna get blasted by this bright target. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC2071 WFPC2 IMAGE PC1-FIX F555W ATD-GAIN=7,CR- 1 40.0S SPLIT=DEF ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC2071 WFPC2 IMAGE PC1-FIX F702W ATD-GAIN=7,CR- 1 200.00S SPLIT=DEF,CLOCK S=YES ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC2071 WFPC2 IMAGE PC1-FIX F555W ATD-GAIN=7,CR- 1 600.00S SPATIAL SCAN 2 SPLIT=DEF,SCAN- READ=ALL,CLOCKS =YES ------------------------------------------------------------------------------------------------------------------------------------ 6134( 28) - 02/22/96 12:55 - [ 9] Visit: 05 Visit Requirements: On Hold Comments: Additional Comments: Schedulers' note: Please leave some time (1-3 hours) after execution of this visit. The WFPC chips are really gonna get blasted by this bright target. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC1333- WFPC2 IMAGE WF3 F555W ATD-GAIN=7,CR- 1 40.0S NORTH SPLIT=DEF ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC1333- WFPC2 IMAGE WF3 F702W ATD-GAIN=7,CR- 1 200.00S NORTH SPLIT=DEF,CLOCK S=YES ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC1333- WFPC2 IMAGE WF3 F555W ATD-GAIN=7,CR- 1 600.00S SPATIAL SCAN 2 NORTH SPLIT=DEF,SCAN- READ=ALL,CLOCKS =YES ------------------------------------------------------------------------------------------------------------------------------------ 6134( 28) - 02/22/96 12:55 - [ 10] Visit: 06 Visit Requirements: ORIENT 130D TO 140D On Hold Comments: Additional Comments: Schedulers' note: Please leave some time (1-3 hours) after execution of this visit. The WFPC chips are really gonna get blasted by this bright target. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC1333- WFPC2 IMAGE WF2 F555W ATD-GAIN=7,CR- 1 40.0S SOUTH SPLIT=DEF ------------------------------------------------------------------------------------------------------------------------------------ 2 NGC1333- WFPC2 IMAGE WF2 F702W ATD-GAIN=7,CR- 1 200.00S SOUTH SPLIT=DEF,CLOCK S=YES ------------------------------------------------------------------------------------------------------------------------------------ 3 NGC1333- WFPC2 IMAGE WF2 F555W ATD-GAIN=7,CR- 1 600.00S SPATIAL SCAN 2 SOUTH SPLIT=DEF,SCAN- READ=ALL,CLOCKS =YES ------------------------------------------------------------------------------------------------------------------------------------ 6134( 28) - 02/22/96 12:55 - [ 11] Scan Paramters Form ------------------------------------------------------------------------------------------------------------------------------------ Data ID: 1 Exposure Logsheet lines: 7.007,7.008,8.007,8.0 FGS Scan: D Dwell Only: dwell points/line: 3 Seconds per dwell: 400.00 Scan width (arc-secs): 0.0000 Scan length (arc-secs): 1.2020 Angle between sides (degrees) 0.00 Number of lines: 1 Scan rate (arc-sec/sec): 0.0000 PA of first scan line (degrees) 45.000 Scan frame (CEL or S/C): S/C Length Offset (arc-sec): Width Offset (arc-sec): ------------------------------------------------------------------------------------------------------------------------------------ Data ID: 2 Exposure Logsheet lines: 9.003,10.003,11.003,1 FGS Scan: D Dwell Only: dwell points/line: 2 Seconds per dwell: 600.00 Scan width (arc-secs): 0.0000 Scan length (arc-secs): 0.6010 Angle between sides (degrees) 0.00 Number of lines: 1 Scan rate (arc-sec/sec): 0.0000 PA of first scan line (degrees) 45.000 Scan frame (CEL or S/C): S/C Length Offset (arc-sec): Width Offset (arc-sec): ------------------------------------------------------------------------------------------------------------------------------------ 6134( 28) - 02/22/96 12:55 - [ 12] Summary Form for Proposal 6134 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ATD-GAIN=7 CR-SPLIT=DEF CLOCKS=YES SCAN-READ=ALL ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Interstellar Medium ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENTation 80D TO 100D SPATIAL SCAN 1 ORIENTation 260D to 280D SPATIAL SCAN 2 ORIENT 130D TO 140D ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F555W F702W ------------------------------------------------------------------------------------------------------------------------------------ Target Names IC348 NGC2068 NGC2071 NGC1333-NORTH NGC1333-SOUTH ------------------------------------------------------------------------------------------------------------------------------------