Astronomy and Astrophysics – Astronomy
Scientific paper
Jan 2012
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012apj...744..121y&link_type=abstract
The Astrophysical Journal, Volume 744, Issue 2, article id. 121 (2012).
Astronomy and Astrophysics
Astronomy
Accretion, Accretion Disks, Atlases, Stars: Pre-Main Sequence, Ultraviolet: Stars
Scientific paper
We present a far-ultraviolet (FUV) spectral atlas consisting of spectra of 91 pre-main-sequence stars. Most stars in this sample were observed with the Space Telescope Imaging Spectrograph and Advanced Camera for Surveys on the Hubble Space Telescope (HST). A few archival spectra from the International Ultraviolet Explorer and the Goddard High Resolution Spectrograph on HST are included for completeness. We find strong correlations among the O I λ1304 triplet, the Si IV λλ1394/1403 doublet, the C IV λ1549 doublet, and the He II λ1640 line luminosities. For classical T Tauri stars (CTTSs), we also find strong correlations between these lines and the accretion luminosity, suggesting that these lines form in processes related to accretion. These FUV line fluxes and X-ray luminosity correlate loosely with large scatters. The FUV emission also correlates well with Hα, Hβ, and Ca II K line luminosities. These correlations between FUV and optical diagnostics can be used to obtain rough estimates of FUV line fluxes from optical observations. Molecular hydrogen (H2) emission is generally present in the spectra of actively accreting CTTSs but not the weak-lined T Tauri stars that are not accreting. The presence of H2 emission in the spectrum of HD 98800 N suggests that the disk should be classified as actively accreting rather than a debris disk. We discuss the importance of FUV radiation, including the hydrogen Lyα line, on the photoevaporation of exoplanet atmospheres. We find that the Ca II/C IV flux ratios for more evolved stars are lower than those for less evolved accretors, indicating preferential depletion of refractory metals into dust grains.
Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Science Institute. STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. This work also contains results from Chandra projects 09200763 and 10200804 supported by SAO grants GO8-9024X and GO9-0020B to the University of Colorado. This work was supported in part by NASA Swift grants NNX09AL59G and NNX10AK88G, and Smithsonian Institution Chandra grants GO8-9024X, GO9-0020B, GO0-11042X, and GO1-12031X to the University of Colorado.
Bergin Edwin
Brown Alexander
Calvet Nuria
Herczeg Gregory J.
Ingleby Laura
No associations
LandOfFree
A Far-ultraviolet Atlas of Low-resolution Hubble Space Telescope Spectra of T Tauri Stars does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with A Far-ultraviolet Atlas of Low-resolution Hubble Space Telescope Spectra of T Tauri Stars, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A Far-ultraviolet Atlas of Low-resolution Hubble Space Telescope Spectra of T Tauri Stars will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-751258