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J/ApJ/784/127        UV spectra of classical T Tauri stars       (France+, 2014)

High-resolution ultraviolet radiation fields of classical T Tauri stars. France K., Schindhelm E., Bergin E.A., Roueff E., Abgrall H. <Astrophys. J., 784, 127 (2014)> =2014ApJ...784..127F (SIMBAD/NED BibCode)
ADC_Keywords: Stars, emission ; Spectra, ultraviolet ; Stars, early-type Keywords: protoplanetary disks - stars: pre-main sequence - ultraviolet: planetary systems Abstract: The far-ultraviolet (FUV; 912-1700 Å) radiation field from accreting central stars in classical T Tauri systems influences the disk chemistry during the period of giant planet formation. The FUV field may also play a critical role in determining the evolution of the inner disk (r<10 AU), from a gas- and dust-rich primordial disk to a transitional system where the optically thick warm dust distribution has been depleted. Previous efforts to measure the true stellar+accretion-generated FUV luminosity (both hot gas emission lines and continua) have been complicated by a combination of low-sensitivity and/or low-spectral resolution and did not include the contribution from the bright Lyα emission line. In this work, we present a high-resolution spectroscopic study of the FUV radiation fields of 16 T Tauri stars whose dust disks display a range of evolutionary states. We include reconstructed Lyα line profiles and remove atomic and molecular disk emission (from H2 and CO fluorescence) to provide robust measurements of both the FUV continuum and hot gas lines (e.g., Lyα, N V, C IV, He II) for an appreciable sample of T Tauri stars for the first time. We find that the flux of the typical classical T Tauri star FUV radiation field at 1 AU from the central star is ∼107 times the average interstellar radiation field. The Lyα emission line contributes an average of 88% of the total FUV flux, with the FUV continuum accounting for an average of 8%. Both the FUV continuum and Lyα flux are strongly correlated with C IV flux, suggesting that accretion processes dominate the production of both of these components. On average, only ∼0.5% of the total FUV flux is emitted between the Lyman limit (912 Å) and the H2(0-0) absorption band at 1110 Å. The total and component-level high-resolution radiation fields are made publicly available in machine-readable format. Description: We present 16 objects from the larger GTO + DAO T Tauri star samples described by Ardila et al. (2013ApJS..207....1A; focusing on the hot gas emission lines) and France et al. (2012, J/ApJ/756/171; focusing on the molecular circumstellar environment). Eleven of the 16 sources were observed as part of the DAO of Tau guest observing program (PID 11616; PI: G. Herczeg), four were part of the COS Guaranteed Time Observing program on protoplanetary disks (PIDs 11533 and 12036; PI: J. Green), and we have included archival STIS observations of the well-studied CTTS TW Hya (Herczeg et al. 2002ApJ...572..310H, 2004ApJ...607..369H), obtained through StarCAT (Ayres 2010, J/ApJS/187/149). The targets were selected by the availability of reconstructed Lyα spectra, as this emission line is a critical component to the intrinsic CTTS UV radiation field (Schindhelm et al. 2012ApJ...756L..23S) and has not been uniformly included in recent studies of the CTTS radiation field (e.g., Ingleby et al. 2011AJ....141..127I; Yang et al. 2012, J/ApJ/744/121). Most of the targets were observed with the medium-resolution FUV modes of COS (G130M and G160M; Green et al. 2012ApJ...744...60G). File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file list.dat 64 48 List of individual spectra sp/* 32 39 Individual spectra
See also: J/A+A/297/391 : T Tauri stars ROSAT survey (Neuhaeuser+, 1995) J/ApJS/187/149 : StarCAT: STIS UV echelle spectra of stars (Ayres, 2010) J/ApJ/744/121 : Far-UV spectroscopy of T Tau stars (Yang+, 2012) J/ApJ/756/171 : HST far-UV survey of H2 emission of T Tau stars (France+, 2012) Byte-by-byte Description of file: list.dat
Bytes Format Units Label Explanations
1- 9 A9 --- Name Star name 11- 40 A30 --- Type Type of spectrum 43- 64 A22 --- FileName Name of the spectrum file in subdirectory sp
Byte-by-byte Description of file (# headlines): sp/*
Bytes Format Units Label Explanations
7- 13 E7.3 0.1nm lambda Wavelength 20- 32 E13.6 10mW/m2/nm Flux Flux at 1 AU
History: Copied at http://cos.colorado.edu/~kevinf/ctts_fuvfield.html
(End) Prepared by Tiphaine Pouvreau [CDS] 02-Jun-2017
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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