HD 99458: First time ever Ap-type star as a δ Scuti pulsator in a short period eclipsing binary?
HD 99458: First time ever Ap-type star as a δ Scuti pulsator in a short period eclipsing binary?
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DOI：
10.1093/mnras/stz1478
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发表时间：
2019-06
影响因子：
4.8
通讯作者：
M. Skarka;P. Kabáth;E. Paunzen;M. Fedurco;J. Budaj;Daniel Dupkala;J. Krtička;A. Hatzes;
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作者：
M. Skarka;P. Kabáth;E. Paunzen;M. Fedurco;J. Budaj;Daniel Dupkala;J. Krtička;A. Hatzes;
我们提出了一个独特的对象的发现，一个化学上奇特的AP型星星显示FI盾牌脉动，是在一个食双星系统的轨道周期短于3 d的约束。因此，HD 99458是一个复杂的天体物理实验室，为同时研究各种往往相互矛盾的物理现象打开了大门。它是在食双星中发现的第一颗Ap型星星。它的轨道周期为2.722 d，是所有已知的化学奇特（CP 2）双星中第二短的。（S Scuti型的脉动在CP 2恒星中也是极其罕见的，并且没有明确的候选者被报道。HD 99458以前被认为是一颗拥有系外行星的星星，但我们使用K2使命的光度观测和新的径向速度测量绝对拒绝了这一假设。伴星是一颗低质量的红星星（M？= 0.45（2）Mo）在倾斜轨道（i = 73.2（6）deg）上，只显示掠食。旋转和轨道周期是同步的，而旋转和轨道轴是错位的。HD 99458是一个值得深入研究的有趣系统。
We present the discovery of a unique object, a chemically peculiar Ap-type star showing fi Scuti pulsations that, is bound in an eclipsing binary system with an orbital period shorter than 3 d. HD 99458 is therefore a complex astrophysical laboratory opening doors for studying various, often contradictory, physical phenomena at the same time. It is the first Ap star ever discovered in an eclipsing binary. The orbital period of 2.722 d is the second shortest among all known chemically peculiar (CP2) binary stars. Pulsations of (S Scuti type are also extremely rare among CP2 stars and no unambiguously proven candidate has been reported. HD 99458 was formerly thought to he a star hosting an exoplanet, but we definitely reject this hypothesis using photometric observations from the K2 mission and new radial velocity measurements. The companion is a low-mass red dwarf star (M? = 0.45(2)Mo) on an inclined orbit (i = 73.2(6) deg) that shows only grazing eclipses. The rotation and orbital periods are synchronized, while the rotation and orbital axes are misaligned. HD 99458 is an interesting system deserving of more intense investigations.