论文标题

Lamost DR8的F型Herbig星的识别和参数测定

Identification and parameter determination of F-type Herbig stars from LAMOST DR8

论文作者

Zhang, Yun-Jin, Luo, A-Li, Jiang, Bi-Wei, Hou, Wen, Zuo, Fang, Du, Bing, Li, Shuo, Zhao, Yong-Heng

论文摘要

我们确定了20位F型Herbig Stars,并提供了Lamost DR8的22名序列前候选列表。根据光谱,光度计,GAIA EDR3可交值和预序列序列进化轨迹,为每个Herbig恒星得出了有效温度,距离,灭绝,恒星光度,质量和半径。根据光谱能量分布,19个F型Herbig Stars属于II级YSO,其中一个属于平面谱类。有四个具有Spitzer IRS光谱,其中三个显示出极弱的多环芳烃排放,三个具有无定形和晶体硅酸盐排放量具有相似的参数,并且处于同一进化阶段。我们检测到太阳能爆发Exor Herbig明星J034344.48+314309.3,这是Herbig Ae Star的可能前体。 HI,HEI,OI,NAI和CAII的强烈发射线源自其光谱中爆发过程中的快速积聚,并在其红外光谱中检测到硅酸盐发射特征。我们还使用定义的红外光谱指数对所有已知的Herbig恒星的磁盘特性进行了统计分析。随着有效温度的升高,中等红外过量的Herbig恒星的比例会降低。大多数前体(F-,G-或K-型)具有适度的红外过量。较热的Herbig恒星往往具有更大的比例,而大型红外过量则具有更大的比例。趋势可能是由于较热的恒星具有更大的重新发射灰尘的事实,尽管由于每个磁盘的特殊性,因此存在一些散射。

We identify 20 F-type Herbig stars and provide a list of 22 pre-main-sequence candidates from LAMOST DR8. The effective temperature, distance, extinction, stellar luminosity, mass, and radius are derived for each Herbig star based on optical spectra, photometry, Gaia EDR3 parallaxes, and pre-main-sequence evolutionary tracks. According to spectral energy distributions, 19 F-type Herbig stars belong to Class II YSOs, and one belongs to the flat-spectrum class. Four have Spitzer IRS spectra, of which three show extremely weak polycyclic aromatic hydrocarbons emissions, and three with both amorphous and crystalline silicate emissions share the similar parameters and are at the same evolutionary stage. We detect a solar-nearby outbursting EXor Herbig star J034344.48+314309.3, possible precursor of a Herbig Ae star. Intense emission lines of HI, HeI, OI, NaI, and CaII originated from the rapid accretion during the outbursts are detected in its optical spectra, and silicate emission features are detected in its infrared spectrum. We also make a statistic analysis on the disk properties of all known Herbig stars using the defined infrared spectral indices. The proportion of Herbig stars with moderate infrared excesses decreases as effective temperature increases. The majority of the precursors (F-, G-, or K- type) have moderate infrared excesses. Hotter Herbig stars tend to have a larger proportion with large infrared excesses. The trends may be due to the fact that hotter stars have larger areas of re-emitting dust, although there is some scatter due to the particularities of each disk.

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