10348( 8) - 06/27/05 07:39 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 10348 Version: 8 Check-in Time: 27-Jun-2005 11:39:21 Title The Production of X-ray Emission in Classical T Tauri Stars ------------------------------------------------------------------------------------ Type Cycle Parallel Pointing Tolerance GO 13 ------------------------------------------------------------------------------------ Investigators Contact? PI: Mr. Gregory J. Herczeg University of Colorado at Boulder CoI: Dr. Jeffrey L. Linsky University of Colorado at Boulder N CoI: Dr. Frederick M. Walter State University of New York at Stony N Brook CoI: Dr. Rachel A. Osten Associated Universities, Inc. N ------------------------------------------------------------------------------------ Abstract We propose to obtain a 150 ks HETG spectrum of the Classical T Tauri Star (CTTS) V4046 Sgr. The unknown source of strong X-ray emission remains a glaring weakness in our understanding of energetics around young stars. An HETG observation of the CTTS TW Hya suggested that the physical properties of the hot gas around accreting stars may be different from solar-like coronae. This difference hints that accretion may produce most of the X-rays from CTTSs. However, this tentative conclusion is based on observations of only one CTTS, that may not be representative of its class. We seek to verify this conclusion, and to obtain a better understanding of the temperature, electron density, and abundances of hot gas around CTTSs, by obtaining a high S/N HETG spectrum of an X-ray bright CTTS. ------------------------------------------------------------------------------------ 10348( 8) - 06/27/05 07:39 - [ 2] Observations Description ------------------------ We will use HST/ACS to obtain low-resolution FUV-NUV-optical spectra of V4046 Sgr to estimate the extinction and mass accretion rate, and FUV radiation field from the star. The observations will consist of SBC PR130L, HRC PR200L, and HRC G800L spectra. CTTSs are variable, particularly in the FUV. To understand our X-ray spectra and the properties of V4046 Sgr during that spectra, we require that these observations must occur contemporaneous (within 1 week) of our Chandra observation of V4046 Sgr. We use an IUE spectrum of V4046 Sgr to calculate FUV and NUV exposure times. We also use optical STIS spectra of TW Hya as a template for V4046 Sgr. We will obtain an optical spectrum of V4046 Sgr with the G800L Grism on the HRC. We calculate an exposure time of 5 s for this optical spectrum to obtain S/N of at least 100 over the wavelength range. The optical spectrum would be saturated in about 31 s. We will obtain one short (11 s) and one longer (62 s) NUV spectrum with the P200L on the HRC. The longer portion of this wavelength range is saturated in about 18 s. The longer exposure will yield S/N of at least 30 across the entire wavelength regime. The 441 s FUV spectrum will result in a S/N of at least 30 across the entire wavelength regime. The maximum count rate per pixel is about 12 at 1550 (C IV). We will also obtain an FUV image of V4046 Sgr using the F165LP filter in order to calibrate the wavelengths in our FUV spectrum. In this image we will detect about 32 cts/s from the source, with the brightest pixel detecting about 6 cts/s. Real Time Justification ----------------------- These observations must occur contemporaneous (within 1 week) of our Chandra observation of V4046 Sgr. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 10348( 8) - 06/27/05 07:39 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 V4046SGR STAR, T TAURI STAR RA=18H14M10.5000S +/- 0.1", J2000 V = 10.5 DEC=-32D47'33.58" +/- 0.5", PLATE-ID=067E Coordinate Source: GUIDE_STAR_CATALOG 10348( 8) - 06/27/05 07:39 - [ 4] Visit: 01 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Needs to be coordinated with Chandra observation of V4046 Sgr Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 V4046SGR ACS/HRC ACCUM HRC F502N 1 214 S ------------------------------------------------------------------------------------------------------------------------------------ 2 V4046SGR ACS/HRC ACCUM HRC F658N 1 214 S ------------------------------------------------------------------------------------------------------------------------------------ 3 V4046SGR ACS/HRC ACCUM HRC F606W 1 0.2 S ------------------------------------------------------------------------------------------------------------------------------------ 4 V4046SGR ACS/HRC ACCUM HRC PR200L AUTOIMAGE=NO 1 10 S ------------------------------------------------------------------------------------------------------------------------------------ 5 V4046SGR ACS/HRC ACCUM HRC PR200L AUTOIMAGE=NO 1 80 S ------------------------------------------------------------------------------------------------------------------------------------ 6 V4046SGR ACS/HRC ACCUM HRC G800L AUTOIMAGE=NO 1 5 S ------------------------------------------------------------------------------------------------------------------------------------ 7 V4046SGR ACS/SBC ACCUM SBC PR130L 1 630 S ------------------------------------------------------------------------------------------------------------------------------------ 8 V4046SGR ACS/SBC ACCUM SBC F165LP 1 30 S ------------------------------------------------------------------------------------------------------------------------------------ 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 | ------------------------------------------------------------------------------------------------------------------------------------ V4046SGR 1 ACS/HRC ACCUM HRC F502N none none none 1 1 N/A V4046SGR 1 ACS/HRC ACCUM HRC F502N none none none 2 1 N/A V4046SGR 2 ACS/HRC ACCUM HRC F658N none none none 1 1 N/A V4046SGR 2 ACS/HRC ACCUM HRC F658N none none none 2 1 N/A V4046SGR 3 ACS/HRC ACCUM HRC F606W none none none 1 1 N/A V4046SGR 3 ACS/HRC ACCUM HRC F606W none none none 2 1 N/A V4046SGR 4 ACS/HRC ACCUM HRC PR200L none none none 1 1 N/A V4046SGR 4 ACS/HRC ACCUM HRC PR200L none none none 2 1 N/A V4046SGR 5 ACS/HRC ACCUM HRC PR200L none none none 1 1 N/A V4046SGR 5 ACS/HRC ACCUM HRC PR200L none none none 2 1 N/A V4046SGR 6 ACS/HRC ACCUM HRC G800L none none none 1 1 N/A V4046SGR 6 ACS/HRC ACCUM HRC G800L none none none 2 1 N/A V4046SGR 7 ACS/SBC ACCUM SBC PR130L none none none none 1 N/A V4046SGR 8 ACS/SBC ACCUM SBC F165LP none none none none 1 N/A 10348( 8) - 06/27/05 07:39 - [ 5] Summary Form for Proposal 10348 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures HRC SBC ------------------------------------------------------------------------------------------------------------------------------------ Configurations ACS/HRC ACS/SBC ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters AUTOIMAGE=NO ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F502N F658N F606W PR200L G800L PR130L F165LP ------------------------------------------------------------------------------------------------------------------------------------ Target Names V4046SGR ------------------------------------------------------------------------------------------------------------------------------------