Aims. The X-shooter archive of several thousand telluric standard star spectra was skimmed for Be and Be shell stars to derive the stellar fundamental parameters and statistical properties, in particular for the less investigated late-type Be stars and the extension of the Be phenomenon into early A stars. Methods. An adapted version of the BCD method is used, using the Balmer discontinuity parameters to determine effective temperature and surface gravity. This method is optimally suited for late B stars. The projected rotational velocity was obtained by profile fitting to the Mg? ii lines of the targets, and the spectra were inspected visually for the presence of peculiar features such as the infrared Ca? ii triplet or the presence of a double Balmer discontinuity. The Balmer line equivalent widths were measured, but they are only useful for determining the pure emission contribution in a subsample of Be stars owing to uncertainties in determining the photospheric contribution. Results. A total of 78, mostly late-type, Be stars, were identified in the X-shooter telluric standard star archive, out of which 48 had not been reported before. We confirm the general trend that late-type Be stars have more tenuous disks and are less variable than early-type Be stars. The relatively large number (48) of relatively bright ( V > 8.5 ) additional Be stars casts some doubt on the statistics of late-type Be stars; they are more common than currently thought. The Be/B star fraction may not strongly depend on spectral subtype.
展开▼
机译：目的对Be和Be壳恒星的X-shooter档案进行了略读，以获取Be和Be壳星，以推导出恒星的基本参数和统计特性，尤其是对于研究较少的晚期Be恒星以及Be现象扩展到早期的情况一个星星。方法。使用修改后的BCD方法，使用Balmer不连续参数确定有效温度和表面重力。此方法最适合后期B星。投影转速是通过对Mg2进行轮廓拟合而获得的。目测目标线，并目视检查光谱中是否存在特殊特征，例如红外Ca 2+。 ii三重态或双Balmer不连续性的存在。测量了巴尔默线的等效宽度，但是由于确定光球作用的不确定性，它们仅用于确定Be恒星子样本中的纯发光作用。结果。在X-shooter碲化物标准恒星档案中总共发现了78颗，大多数是晚型Be恒星，其中48颗以前从未被报道过。我们证实了总体趋势，即晚型Be恒星比早型Be恒星具有更多的微弱盘，并且变化较小。相对较多（48> 8.5）的额外Be恒星的数量相对较多（48），对后期型Be恒星的统计数据产生了一些疑问。它们比当前的想法更为普遍。 Be / B星的比例可能在很大程度上不取决于光谱亚型。
展开▼
