Infall and Outflow Activities in the Be star FY CMa  

作　　者：Hui-Lai Cao National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 CAS-PKU Joint Beijing Astrophysics Center, Peking University, Beijing 100871 

出　　处：《Chinese Journal of Astronomy and Astrophysics》2001年第6期514-524,共11页中国天文和天体物理学报（英文版）

基　　金：This work was performed under the auspices of Max-Planck Society of Germany;the National NaturaI Science Foundation of China

摘　　要：Unusual activity of outflow mass motion connected with infall events was recorded for the B0.5 IVe star FY CMa in February 1987 from both archival IUE spectrograms of circumstellar N v resonance lines and optical spectra of Ha and HeI γ5876 A emission lines which showed inverse P Cygni-type profiles. We estimate the mass loss rate using ultraviolet Si IVresonance lines with expanding atmosphere modeling calculations, and describe how the radial pressure performs the dominant role in accelerating the stellar wind. We attempt to give a qualitative explanation for the activity observed for FY CMa in terms of circumstellar matter raining down to the star.Unusual activity of outflow mass motion connected with infall events was recorded for the B0.5 IVe star FY CMa in February 1987 from both archival IUE spectrograms of circumstellar N v resonance lines and optical spectra of Ha and HeI γ5876 A emission lines which showed inverse P Cygni-type profiles. We estimate the mass loss rate using ultraviolet Si IVresonance lines with expanding atmosphere modeling calculations, and describe how the radial pressure performs the dominant role in accelerating the stellar wind. We attempt to give a qualitative explanation for the activity observed for FY CMa in terms of circumstellar matter raining down to the star.

关 键 词：line: proffles - stars: activity - stars: emission-line Be -circumstellar matter - stars: mass-loss - ultraviolet: stars 

分 类 号：P144[天文地球—天体物理]