dc.contributor.author |
Manoj, P |
|
dc.contributor.author |
Bhatt, H. C |
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dc.contributor.author |
Maheswar, G |
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dc.contributor.author |
Muneer, S |
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dc.date.accessioned |
2007-06-18T06:40:47Z |
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dc.date.available |
2007-06-18T06:40:47Z |
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dc.date.issued |
2006-12-10 |
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dc.identifier.citation |
The Astrophysical Journal, Vol. 653, pp. 657 - 674 |
en |
dc.identifier.uri |
http://hdl.handle.net/2248/1658 |
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dc.description.abstract |
We present optical spectra of 45 intermediate-mass Herbig Ae/Be stars. Together with the multiepoch spectroscopic and photometric data compiled for a large sample of these stars and ages estimated for individual stars by using pre–main-sequence evolutionary tracks, we have studied the evolution of emission-line activity in them. We find that, on average, the Hα emission line strength decreases with increasing stellar age in Herbig Ae/Be stars, indicating that the accretion activity gradually declines during the pre–main-sequence phase. This would hint at a relatively long-lived (a few Myr) process being responsible for the cessation of accretion in Herbig Ae/Be stars. We also find that the accretion activity in these stars drops substantially by ∼3 Myr. This is comparable to the timescale in which most intermediate-mass stars are thought to lose their inner disks, suggesting that inner disks in intermediate-mass stars are dissipated rapidly after the accretion activity has fallen below a certain level. We further find a relatively tight correlation between strength of the emission line and near-infrared excess due to inner disks in Herbig Ae/Be stars, indicating that the disks around Herbig Ae/Be stars cannot be entirely passive. We suggest that this correlation can be understood within the framework of the puffed-up inner rim disk models if the radiation from the accretion shock is also responsible for the disk heating. |
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dc.format.extent |
420039 bytes |
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dc.format.mimetype |
application/pdf |
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dc.language.iso |
en |
en |
dc.publisher |
American Astronomical Society |
en |
dc.relation.uri |
http://lanl.arxiv.org/abs/astro-ph/0608541 |
en |
dc.relation.uri |
http://www.iop.org/EJ/abstract/0004-637X/653/1/657 |
en |
dc.subject |
Circumstellar matter |
en |
dc.subject |
Planetary systems |
en |
dc.subject |
Protoplanetary disks |
en |
dc.subject |
Stars: emission-line, Be |
en |
dc.subject |
Stars: pre-main sequence |
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dc.subject |
Techniques: spectroscopic |
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dc.title |
Evolution of emission line activity in intermediate mass young stars |
en |
dc.type |
Article |
en |