8894( 3) - 02/05/01 15:28 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 8894 Version: 3 Check-in Date: 05-Feb-2001 15:28:03 1.Proposal Title: Accretion Disks in the Orion Nebula ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 9 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Steven Beckwith Space Telescope Science Institute CoI: M. Robberto STScI Y CoI: R. Makidon STScI N CoI: N. Panagia STScI N ------------------------------------------------------------------------------------ 5. Abstract We propose to perform UB-band imaging of the Orion Nebula Cluster in order to derive for the first time the disk accretion rates of the pre-main-sequence objects, and to study with unprecented resolution and sensitivity the dark silhouette disks. Since for ~1000 stars the spectral types and extinction are known, WFPC2 images in the 330W filter will directly provide the U-band excesses. It has been shown recently that the U-band excess is strongly correlated with the disk accretion luminosity, and therefore with the accretion rate. We will compare the accretion rates with the stellar parameters, measured or derived by matching the source positions in the HR diagram with theoretical evolutionary tracks, and with the IR excesses. Correlations with quantities like mass, age, position, etc. will provide fundamental insights on the star formation process in Orion. The database of accretion rates will be the richest ever built for this class of phenomena. The dark silhouette disks of the Orion Nebula will be studied exploiting the simultaneous increase of spatial resolution and dust extinction in the U-band. A higher sensitivity to lower column densities will not only improve our understanding of these objects (density distribution, truncation, etc.) but also enable the discovery of fainter silhouette disks, possibly in a more evolved evolutionary phase. ------------------------------------------------------------------------------------ 8894( 3) - 02/05/01 15:28 - [ 2] Observations Description ------------------------ We will perform U and B band imaging of 4 fields in the core of the Orion Nebula. For the U band, we use as a baseline an integration time of 400s (choosen in order to minimize overheads). Repeating four exposures at the same field position the total integration time will be 1600 s. One exposure will also be taken with 1s and 30s integration time, for the brightest objects. For the B-band, we shall do 2 exposures 160 s long for each pointing. Short exposures of 1s and 20 s will avoid saturation of bright sources. With proper pointing and rotation, 4-fields can cover the central part of the nebula. With the position/orientation angle we assumed, the Trapezium and theta-2 Ori are centered on the PC camera. This will reduce as much as possible the area interested by CCD bleeding. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- None ------------------------------------------------------------------------------------ 8894( 3) - 02/05/01 15:28 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 ORION-NEBULA STELLAR CLUSTER RA=5H 35M 17.00S +/- 1", DEC=-5D J2000 SURF-BKG(B) = 18.0+/-0.5 -TRAP.CENTER 23' 27.00" +/- 1" Coordinate Source: OTHER_SOURCE Comments: This is the main frame with PC at the center of the Trapezium. =========== Hi Massimo, The Visual Target Tuner comes up with the following positions for the four ONC fields - all in J2000.0 coordinates. Field 1: 05h 35m 17.00s -05d 23' 27.00" Field 2: 05h 35m 18.85s -05d 21' 35.49" Field 3: 05h 35m 25.49s -05d 23' 24.96" Field 4: 05h 35m 22.91s -05d 25' 09.37" 2 ORION-NEBULA STELLAR CLUSTER RA=5H 35M 18.85S +/- 1", DEC=-5D J2000 SURF-BKG(B) = 18.0+/-0.5 -FIELD2 21' 35.49" +/- 1" Coordinate Source: OTHER_SOURCE Comments: up-left field. ============ Hi Massimo, The Visual Target Tuner comes up with the following positions for the four ONC fields - all in J2000.0 coordinates. Field 1: 05h 35m 17.00s -05d 23' 27.00" Field 2: 05h 35m 18.85s -05d 21' 35.49" Field 3: 05h 35m 25.49s - 05d 23' 24.96" Field 4: 05h 35m 22.91s -05d 25' 09.37" 3 ORION-NEBULA STELLAR CLUSTER RA=5H 35M 25.49S +/- 1", DEC=-5D J2000 SURF-BKG(B) = 18.0+/-0.5 -FIELD3 23' 24.96" +/- 1" Coordinate Source: OTHER_SOURCE Comments: down-left field Hi Massimo, ================ The Visual Target Tuner comes up with the following positions for the four ONC fields - all in J2000.0 coordinates. Field 1: 05h 35m 17.00s -05d 23' 27.00" Field 2: 05h 35m 18.85s -05d 21' 35.49" Field 3: 05h 35m 25.49s -05d 23' 24.96" Field 4: 05h 35m 22.91s - 05d 25' 09.37" 4 ORION-NEBULA STELLAR CLUSTER RA=5H 35M 22.91S +/- 1", DEC=-5D J2000 SURF-BKG(B) = 18.0+/-0.5 -POS4 25' 9.37" +/- 1" Coordinate Source: OTHER_SOURCE Comments: theta2Ori Hi Massimo, ================ The Visual Target Tuner comes up with the following positions for the four ONC fields - all in J2000.0 coordinates. Field 1: 05h 35m 17.00s -05d 23' 27.00" Field 2: 05h 35m 18.85s -05d 21' 35.49" Field 3: 05h 35m 25.49s - 05d 23' 24.96" Field 4: 05h 35m 22.91s -05d 25' 09.37" 8894( 3) - 02/05/01 15:28 - [ 4] Visit: 01 Visit Priority: Visit Requirements: ORIENT 80D TO 80D BEFORE 01-Jun-2001 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 ORION-NEBUL WFPC2 IMAGE PC1 F336W 1 1 S A-TRAP.CENT ER ------------------------------------------------------------------------------------------------------------------------------------ 20 ORION-NEBUL WFPC2 IMAGE PC1 F336W 1 30 S A-TRAP.CENT ER ------------------------------------------------------------------------------------------------------------------------------------ 30 ORION-NEBUL WFPC2 IMAGE PC1 F336W 4 400 S NO SPLIT A-TRAP.CENT ER ------------------------------------------------------------------------------------------------------------------------------------ 40 ORION-NEBUL WFPC2 IMAGE PC1 F439W 1 1 S A-TRAP.CENT ER ------------------------------------------------------------------------------------------------------------------------------------ 50 ORION-NEBUL WFPC2 IMAGE PC1 F439W 1 30 S A-TRAP.CENT ER ------------------------------------------------------------------------------------------------------------------------------------ 60 ORION-NEBUL WFPC2 IMAGE PC1 F439W CR-SPLIT=0.5 1 320 S A-TRAP.CENT ER ------------------------------------------------------------------------------------------------------------------------------------ 70 ORION-NEBUL WFPC2 IMAGE PC1 F336W 1 1 S A-FIELD2 ------------------------------------------------------------------------------------------------------------------------------------ 80 ORION-NEBUL WFPC2 IMAGE PC1 F336W 1 30 S A-FIELD2 ------------------------------------------------------------------------------------------------------------------------------------ 90 ORION-NEBUL WFPC2 IMAGE PC1 F336W 4 400 S NO SPLIT A-FIELD2 ------------------------------------------------------------------------------------------------------------------------------------ 100 ORION-NEBUL WFPC2 IMAGE PC1 F439W 1 1 S A-FIELD2 ------------------------------------------------------------------------------------------------------------------------------------ 110 ORION-NEBUL WFPC2 IMAGE PC1 F439W 1 30 S A-FIELD2 ------------------------------------------------------------------------------------------------------------------------------------ 120 ORION-NEBUL WFPC2 IMAGE PC1 F439W CR-SPLIT=0.5 1 320 S A-FIELD2 ------------------------------------------------------------------------------------------------------------------------------------ 130 ORION-NEBUL WFPC2 IMAGE PC1 F336W 1 1 S A-FIELD3 ------------------------------------------------------------------------------------------------------------------------------------ 8894( 3) - 02/05/01 15:28 - [ 5] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 140 ORION-NEBUL WFPC2 IMAGE PC1 F336W 1 30 S A-FIELD3 ------------------------------------------------------------------------------------------------------------------------------------ 150 ORION-NEBUL WFPC2 IMAGE PC1 F336W 4 400 S NO SPLIT A-FIELD3 ------------------------------------------------------------------------------------------------------------------------------------ 160 ORION-NEBUL WFPC2 IMAGE PC1 F439W 1 1 S A-FIELD3 ------------------------------------------------------------------------------------------------------------------------------------ 170 ORION-NEBUL WFPC2 IMAGE PC1 F439W 1 30 S A-FIELD3 ------------------------------------------------------------------------------------------------------------------------------------ 180 ORION-NEBUL WFPC2 IMAGE PC1 F439W CR-SPLIT=0.5 1 320 S A-FIELD3 ------------------------------------------------------------------------------------------------------------------------------------ 190 ORION-NEBUL WFPC2 IMAGE PC1 F336W 1 1 S A-POS4 ------------------------------------------------------------------------------------------------------------------------------------ 200 ORION-NEBUL WFPC2 IMAGE PC1 F336W 1 30 S A-POS4 ------------------------------------------------------------------------------------------------------------------------------------ 210 ORION-NEBUL WFPC2 IMAGE PC1 F336W 4 400 S NO SPLIT A-POS4 ------------------------------------------------------------------------------------------------------------------------------------ 220 ORION-NEBUL WFPC2 IMAGE PC1 F439W 1 1 S A-POS4 ------------------------------------------------------------------------------------------------------------------------------------ 230 ORION-NEBUL WFPC2 IMAGE PC1 F439W 1 30 S A-POS4 ------------------------------------------------------------------------------------------------------------------------------------ 240 ORION-NEBUL WFPC2 IMAGE PC1 F439W CR-SPLIT=0.5 1 320 S A-POS4 ------------------------------------------------------------------------------------------------------------------------------------ 8894( 3) - 02/05/01 15:28 - [ 6] Summary Form for Proposal 8894 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PC1 ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=0.5 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 80D TO 80D BEFORE 01-Jun-2001 NO SPLIT ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F336W F439W ------------------------------------------------------------------------------------------------------------------------------------ Target Names ORION-NEBULA-TRAP.CENTER ORION-NEBULA-FIELD2 ORION-NEBULA-FIELD3 ORION-NEBULA-POS4 ------------------------------------------------------------------------------------------------------------------------------------