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 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 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 2002ApJ...572..310H, 2004ApJ...607..369H 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 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 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 2012ApJ...744...60G).
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
list.dat 64 48 List of individual spectra
sp/* . 39 Individual spectra
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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
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Bytes Format Units Label Explanations
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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
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Byte-by-byte Description of file (#): 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
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History:
Copied at http://cos.colorado.edu/~kevinf/ctts_fuvfield.html
(End) Prepared by Tiphaine Pouvreau [CDS] 02-Jun-2017