论文标题
发现Lambda Bootis Stars -Southern调查II
The Discovery of lambda Bootis Stars -- The Southern Survey II
论文作者
论文摘要
$λ$ boo恒星是化学上特殊的A型星，其丰度异常与金属贫困材料的积聚有关。我们在针对性的金属效果和发射线恒星的针对性调查中搜索了南半球的$λ$ boo恒星。获取308颗恒星的光谱并在MK系统上分类时，我们发现或共同发现了24个新的$λ$ boo Star。我们还修改了11个已知$λ$ boo星的分类，其中一颗是化学正常的快速旋转器。我们表明，以前在文献中将恒星分类为蓝色水平分支星星或发射线A恒星具有很高的可能性是$λ$ boo boo恒星，尽管该结论基于小数字统计。使用明智的红外通量，我们搜索了目标，以搜索可能归因于原球门或碎屑盘作为增生材料来源的红外过量。在我们样本中的34 $λ$ boo恒星中，有21个主要序列年龄有超额过量，证实并非所有$λ$ boo boo stars都年轻。
The $λ$ Boo stars are chemically peculiar A-type stars whose abundance anomalies are associated with the accretion of metal-poor material. We searched for $λ$ Boo stars in the southern hemisphere in a targeted spectroscopic survey of metal-weak and emission-line stars. Obtaining spectra for 308 stars and classifying them on the MK system, we found or co-discovered 24 new $λ$ Boo stars. We also revised the classifications of 11 known $λ$ Boo stars, one of which turned out to be a chemically normal rapid rotator. We show that stars previously classified in the literature as blue horizontal branch stars or emission-line A stars have a high probability of being $λ$ Boo stars, although this conclusion is based on small-number statistics. Using WISE infrared fluxes, we searched our targets for infrared excesses that might be attributable to protoplanetary or debris discs as the source of the accreted material. Of the 34 $λ$ Boo stars in our sample, 21 at various main-sequence ages have infrared excesses, confirming that not all $λ$ Boo stars are young.
