SIMBAD references

2006ApJ...653..657M - Astrophys. J., 653, 657-674 (2006/December-2)

Evolution of emission-line activity in intermediate-mass young stars.


Abstract (from CDS):

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.

Abstract Copyright:

Journal keyword(s): Stars: Circumstellar Matter - Stars: Planetary Systems: Protoplanetary Disks - Stars: Emission-Line, Be - Stars: Pre-Main-Sequence - Techniques: Spectroscopic

VizieR on-line data: <Available at CDS (J/ApJ/653/657): table1.dat table2.dat table3.dat table4.dat table5.dat refs.dat>

Simbad objects: 92

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