Irregular changes in Hα emission line of V423 Aur observed by LAMOST Medium-Resolution Spectrographs

Abstract

We obtained 7 spectra of the Be star V423 Aur on Dec. 5th, 2017 using the LAMOST Medium-Resolution Spectrograph with exposures from 600 to 1200 seconds. These spectra show the irregular Hα emission line profile variations (LPVs). In the seven spectra, from the 4th to 7th, the left part of Hα profile even show excess. However, no variation can be seen from the follow-up observation of photometry by 1.26-m telescope and High-Resolution spectra by 2.16-m telescope. According to the High-Resolution spectra, we conclude that it is a B7V type star with E(B-V)= 0.709{\pm}0.036 and its vsini is {\sim} 221.8km/s. The short-term Hα LPVs could be explained as a result of the transient ejection of matter from rotating disk or shell around V423 Aur.

arXiv commentAccepted for publication in RAA

References in corpus (8)

• Estimating distances from parallaxes IV: Distances to 1.33 billion stars in Gaia Data Release 2
• Classical Be Stars: Rapidly Rotating B Stars with Viscous Keplerian Decretion Disks
• Stellar and substellar companions of nearby stars from Gaia DR2 - Binarity from proper motion anomaly
• The IACOB project: I. Rotational velocities in Northern Galactic O and early B-type stars revisited. The impact of other sources of line-broadening
• New grids of ATLAS9 atmospheres I: Influence of convection treatments on model structure and on observable quantities
• A Catalogue of OB Stars from LAMOST Spectroscopic Survey
• A Complete Census of Luminous Stellar Variability on Day to Decade Timescales
• Ultraviolet Spectrophotometry of Variable Early-Type Be and B stars Derived from High-Resolution IUE Data

Cited by in corpus (4)

• LAMOST Medium-Resolution Spectral Survey of Galactic Nebula (LAMOST MRS-N): An overview of Scientific goals and Survey plan
• On the radial velocity calibrations in the LAMOST Medium-Resolution Spectroscopic Survey of Nebulae
• LAMOST Medium-Resolution Spectral Survey of Galactic Nebulae (LAMOST-MRS-N): Subtraction of Geocoronal Halpha Emission
• The Data Processing of the LAMOST Medium-Resolution Spectral Survey of Galactic Nebulae (LAMOST MRS-N Pipeline)