11199( 2) - 05/11/07 09:11 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 11199 Version: 2 Check-in Time: 11-May-2007 13:10:57 STScI Edit Number: 0 Title A Hard Look at Stellar Disks at the Epoch of Planet Formation ------------------------------------------------------------------------------------ Type Cycle Parallel Pointing Tolerance GO 16 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Lee W. Hartmann University of Michigan CoI: Dr. Cesar Briceno Centro de Investigaciones de Astronomia N CoI: Dr. Nuria Calvet University of Michigan N CoI: Dr. Jesus Hernandez University of Michigan N CoI: Ms. Catherine Espaillat University of Michigan N CoI: Dr. Edwin Anthony Bergin University of Michigan N CoI: Dr. Jon Matthew Miller University of Michigan N CoI: Dr. Gregory J. Herczeg California Institute of Technology N ------------------------------------------------------------------------------------ Abstract We propose to use HST/ACS/SBC and Chandra/ACIS-S3 to observe the high energy fluxes of 4 stars surrounded by disks in the newly discovered aggregate 25 Ori, the most populous 10 Myr group known within 500 pc. Our observations will cover the 1-25A and 1250-2000A bandpasses, and will complement our optical and Spitzer data for these objects, to provide essential input to physically-consistent models of disk structure and chemistry in the age range around 10 Myr, thought to be a critical period in the planet-forming process. We will be able to determine the Ne/O ratio and determine if the anomalous metal abundances observed in X-ray spectra of young stars are an evolutionary or an environmental effect. Our proposed observations will double the number of 10 Myr old accreting stars with known high energy radiation fields, and will be the first FUV observations of low mass accreting stars in an OB association. ------------------------------------------------------------------------------------ 11199( 2) - 05/11/07 09:11 - [ 2] Observations Description ------------------------ ACS prism observations are being made of 4 young stellar objects in 25 Ori to study the FUV continuum of these objects. The spectral element is the PR130L being used with the ACS/SBC. A single observation of an orbit in length is scheduled for OB1A-776 and OB1A-1192. For OB1A-1200 and OB1A-1630, the observation will be 2 orbits in length. A pair of short observations is also scheduled, as these are needed for wavelength calibration. The pair of short images is being taken with the F140LP filter on the SBC/ACS. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- One of our targets (OB1A-1192) was identified by the BOT tool as posing a hazard to the ACS/SBC based on assuming an incorrect spectral type of 05. The correct spectral type for this object is K7. Within the visit for this object, BOT also identifies the following target as a hazard: N91A012945 at 05 25 47, +01 45 38.34. However, plotting this object on a 2MASS color-color diagram shows that it cannot be higher than an F0 star and it therefore falls within the limits of Table 7.4 in the ACS handbook. ------------------------------------------------------------------------------------ 11199( 2) - 05/11/07 09:11 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 OB1A-776 STAR, T TAURI STAR RA=05H24M41.0400S +/- 0.1", J2000 V = 14.93 DEC=+01D54'38.63" +/- 0.1" Reference Frame: Other: 2MASS 2 OB1A-1192 STAR, T TAURI STAR RA=05H25M45.8900S +/- 0.1", J2000 V = 14.72 DEC=+01D45'50.08" +/- 0.1" Reference Frame: Other: 2MASS 3 OB1A-1200 STAR, T TAURI STAR RA=05H25M46.7500S +/- 0.1", J2000 V = 17.21 DEC=+01D43'30.30" +/- 0.1" Reference Frame: Other: 2MASS 4 OB1A-1630 STAR, T TAURI STAR RA=05H26M55.3800S +/- 0.1", J2000 V = 16.68 DEC=+01D40'22.48" +/- 0.1" Reference Frame: Other: 2MASS 11199( 2) - 05/11/07 09:11 - [ 4] Visit: 01 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 OB1A-776 ACS/SBC ACCUM SBC F140LP 2 360 S see below ------------------------------------------------------------------------------------------------------------------------------------ 2 OB1A-776 ACS/SBC ACCUM SBC PR130L 2 1800 S see below ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ OB1A-776 1 ACS/SBC ACCUM SBC F140LP none none 1 none 1 108.0 S OB1A-776 1 ACS/SBC ACCUM SBC F140LP none none 2 none 1 108.0 S OB1A-776 2 ACS/SBC ACCUM SBC PR130L none none 1 none 1 1148.0 S OB1A-776 2 ACS/SBC ACCUM SBC PR130L none none 2 none 1 1148.0 S 11199( 2) - 05/11/07 09:11 - [ 5] Visit: 02 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 OB1A-1192 ACS/SBC ACCUM SBC F140LP 2 360 S see below ------------------------------------------------------------------------------------------------------------------------------------ 2 OB1A-1192 ACS/SBC ACCUM SBC PR130L 2 1800 S see below ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ OB1A-1192 1 ACS/SBC ACCUM SBC F140LP none none 1 none 1 108.0 S OB1A-1192 1 ACS/SBC ACCUM SBC F140LP none none 2 none 1 108.0 S OB1A-1192 2 ACS/SBC ACCUM SBC PR130L none none 1 none 1 1148.0 S OB1A-1192 2 ACS/SBC ACCUM SBC PR130L none none 2 none 1 1148.0 S 11199( 2) - 05/11/07 09:11 - [ 6] Visit: 03 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 OB1A-1200 ACS/SBC ACCUM SBC F140LP 1 360 S see below ------------------------------------------------------------------------------------------------------------------------------------ 2 OB1A-1200 ACS/SBC ACCUM SBC PR130L 1 2600 S see below ------------------------------------------------------------------------------------------------------------------------------------ 3 OB1A-1200 ACS/SBC ACCUM SBC F140LP 1 360 S see below ------------------------------------------------------------------------------------------------------------------------------------ 4 OB1A-1200 ACS/SBC ACCUM SBC PR130L 1 2600 S see below ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ OB1A-1200 1 ACS/SBC ACCUM SBC F140LP none none none none 1 256.0 S OB1A-1200 2 ACS/SBC ACCUM SBC PR130L none none none none 1 2313.0 S OB1A-1200 3 ACS/SBC ACCUM SBC F140LP none none none none 2 256.0 S OB1A-1200 4 ACS/SBC ACCUM SBC PR130L none none none none 2 2336.0 S 11199( 2) - 05/11/07 09:11 - [ 7] Visit: 04 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 OB1A-1630 ACS/SBC ACCUM SBC F140LP 1 360 S see below ------------------------------------------------------------------------------------------------------------------------------------ 2 OB1A-1630 ACS/SBC ACCUM SBC PR130L 1 2600 S see below ------------------------------------------------------------------------------------------------------------------------------------ 3 OB1A-1630 ACS/SBC ACCUM SBC F140LP 1 360 S see below ------------------------------------------------------------------------------------------------------------------------------------ 4 OB1A-1630 ACS/SBC ACCUM SBC PR130L 1 2600 S see below ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ OB1A-1630 1 ACS/SBC ACCUM SBC F140LP none none none none 1 256.0 S OB1A-1630 2 ACS/SBC ACCUM SBC PR130L none none none none 1 2313.0 S OB1A-1630 3 ACS/SBC ACCUM SBC F140LP none none none none 2 256.0 S OB1A-1630 4 ACS/SBC ACCUM SBC PR130L none none none none 2 2336.0 S 11199( 2) - 05/11/07 09:11 - [ 8] Summary Form for Proposal 11199 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures SBC ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/SBC ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F140LP PR130L ------------------------------------------------------------------------------------------------------------------------------------ Target Names OB1A-776 OB1A-1192 OB1A-1200 OB1A-1630 ------------------------------------------------------------------------------------------------------------------------------------