首页     开始     To Survive in the Universe    
Inhabited Sky
    News@Sky     天文图片     收集     论坛     Blog New!     常见问题     新闻     登录  

HD 207802


目录

图像

上传图像

DSS Images   Other Images


相关文章

Discovery and analysis of p-mode and g-mode oscillations in the A-type primary of the eccentric binary HD 209295*
We have discovered both intermediate-order gravity mode and low-orderpressure mode pulsation in the same star, HD 209295. It is thereforeboth a γ Doradus and a δ Scuti star, which makes it thefirst pulsating star to be a member of two classes. The analysis of our128h of multisite spectroscopic observations carried out over twoseasons reveals that the star is a single-lined spectroscopic binarywith an orbital period of 3.10575+/-0.00010d and an eccentricity of0.352+/-0.011. Only weak pulsational signals are found in both theradial velocity and line-profile variations, but we have succeeded inshowing that the two highest-amplitude γ Doradus pulsation modesare consistent with l=1 and |m|=1. These two modes dominated our 280h ofBVIC multisite photometry, also obtained over two seasons. Wedetected altogether ten frequencies in the light variations, one in theδ Scuti regime and nine in the γ Doradus domain. Five of theγ Doradus frequencies are exact integer multiples of the orbitalfrequency. This observation leads us to suspect they are tidallyexcited. Attempts to identify modes from the multicolour photometryfailed. We performed model calculations and a stability analysis of thepulsations. The frequency range in which δ Scuti modes are excitedagrees well with observations. However, our models do not showexcitation of γ Doradus pulsations, although the damping issmaller in the observed range. We also investigated tidal excitation ofγ Doradus modes. Some of the observed harmonics of the orbitalperiod were found to be unstable. The observed orbital harmonics whichare stable in the models can be understood as linear combinations of theunstable modes. We could not detect the secondary component of thesystem in infrared photometry, suggesting that it may not be amain-sequence star. Archival data of this star show that it has a strongultraviolet (UV) excess, the origin of which is not known. The orbit ofthe primary is consistent with a secondary mass ofM>1.04Msolar, which is indicative of a neutron star,although a white dwarf companion is not ruled out.

提交文章


相关链接

  • - 没有找到链接 -
提交链接


下列团体成员


观测天体数据

星座:印第安座
右阿森松:21h53m59.30s
赤纬:-63°06'13.9"
视星:7.873
距离:331.126 天文距离
右阿森松适当运动:15.6
赤纬适当运动:-10
B-T magnitude:7.856
V-T magnitude:7.872

目录:
适当名称   (Edit)
HD 1989HD 207802
TYCHO-2 2000TYC 9119-690-1
USNO-A2.0USNO-A2 0225-31328583
HIPHIP 108093

→ 要求更多目录从vizier