Optical spectroscopic variability of Herbig Ae/Be stars

Details Optical spectroscopic variability of Herbig Ae/Be stars Optical spectroscopic variability of Herbig Ae/Be stars

2011-02-24

arxiv.org/abs/1102.5033v1

A&A, 529, (2011), A34

Astronomy and Astrophysics

Astrophysics

Solar and Stellar Astrophysics

10 pages, 5 figures, 2 appendixes

Scientific paper

10.1051/0004-6361/201015821

We analysed 337 multi-epoch optical spectra of 38 Herbig Ae/Be (HAeBe) stars to gain insights into the variability behaviour of the circumstellar (CS) atomic gas. Equivalent widths (EWs) and line fluxes of the Halpha, [OI]6300, HeI5876 and NaID lines were obtained for each spectrum; the Halpha line width at 10% of peak intensity (W10) and profile shapes were also measured and classified. The mean line strengths and relative variabilities were quantified for each star. Simultaneous optical photometry was used to estimate the line fluxes. We present a homogeneous spectroscopic database of HAeBe stars. The lines are variable in practically all stars and timescales, although 30 % of the objects show a constant EW in [OI]6300, which is also the only line that shows no variability on timescales of hours. The HeI5876 and NaID EW relative variabilities are typically the largest, followed by those in [OI]6300 and Halpha. The EW changes can be larger than one order of magnitude for the HeI5876 line, and up to a factor 4 for Halpha. The [OI]6300 and Halpha EW relative variabilities are correlated for most stars in the sample. The Halpha mean EW and W10 are uncorrelated, as are their relative variabilities. The Halpha profile changes in 70 % of the objects. The massive stars in the sample usually show more stable Halpha profiles with blueshifted self-absorptions and less variable 10% widths. Our data suggest multiple causes for the different line variations, but the [OI]6300 and Halpha variability must share a similar origin in many objects. The physical mechanism responsible for the Halpha line broadening does not depend on the amount of emission; unlike in lower-mass stars, physical properties based on the Halpha luminosity and W10 would significantly differ. Our results provide additional support to previous works that reported different physical mechanisms in Herbig Ae and Herbig Be stars.

Affiliated with

Also associated with

No associations

Rating

Optical spectroscopic variability of Herbig Ae/Be 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 Optical spectroscopic variability of Herbig Ae/Be stars, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Optical spectroscopic variability of Herbig Ae/Be stars will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-87002