论文标题
两种受gaia的年轻恒星物体的爆发样的光度和光谱研究
Photometric and spectroscopic study of the burst-like brightening of two Gaia-alerted young stellar objects
论文作者
论文摘要
年轻的恒星在数小时到几十年中显示出不同时间量表的可变性，并具有一系列振幅。我们研究了两颗年轻的明星，这触发了Gaia Science警报系统，因为一年的时间尺度上的亮度。 GAIA20BWA亮了大约一半，而Gaia20fgx的亮度大约为两个半幅度。我们分析了用望远镜纳粹盖利洛（Nazionale Galileo）和Gran望远镜加拿大省（Gran Telescopio Canarias）拍摄的Gaia光曲线，附加的光度法和光谱。检测到几条向GAIA20BWA检测到的几条排放线，包括从H $α$到H $δ$，PA $β$，Br $γ$，以及Ca II，O I和NaI的线。H$α$α$和BR $γ$线条在其光明中的其他cy $ cy cy cy cy cy and cy cy cy and pa $ cy and pa $ cy cy and pa $ cy cy cy and cy cy in cy cy cy cy cy cy cy cy cy and and a h $β$，br $γ$，和ca ii，br $γ$，以及pa $ cy cy and cy cy cy。褪色。基于Br $γ$行，GAIA20BWA的增生率为$（2.4-3.1）\ times10^{ - 8} $ $ m_ \ odot $ yr $^{ - 1} $ for Gaia20bwa和$（4.5-6.6.6.6）\ times1010^{ - 8} $ m_ \ odot $ m_ \ m_ \ odot $ $ $ yr $ yr $ yr $ yr $ yr $ yr $ yr $ yr $ yraia。 GAIA20FGX的积聚率在半年时间尺度上下降了几乎10倍。发现这两颗恒星的吸积参数与经典T牛里恒星的吸积参数相似，低于年轻的喷发恒星。但是，这些亮丽的幅度和时间尺度将这些恒星置于参数空间的一个区域，这很少被年轻的恒星填充。这表明了一类新的年轻明星，它们在类似于年轻的爆发星的时间尺度上产生爆发，但幅度较小。
Young stars show variability on different time-scales from hours to decades, with a range of amplitudes. We studied two young stars, which triggered the Gaia Science Alerts system due to brightenings on a time-scale of a year. Gaia20bwa brightened by about half a magnitude, whereas Gaia20fgx brightened by about two and half magnitudes. We analyzed the Gaia light curves, additional photometry, and spectra taken with the Telescopio Nazionale Galileo and the Gran Telescopio Canarias. Several emission lines were detected toward Gaia20bwa, including hydrogen lines from H$α$ to H$δ$, Pa$β$, Br$γ$, and lines of Ca II, O I, and Na I. The H$α$ and Br$γ$ lines were detected toward Gaia20fgx in emission in its bright state, with additional CO lines in absorption, and the Pa$β$ line with an inverse P Cygni profile during its fading. Based on the Br$γ$ lines the accretion rate was $(2.4-3.1)\times10^{-8}$ $M_\odot$ yr$^{-1}$ for Gaia20bwa and $(4.5-6.6)\times10^{-8}$ $M_\odot$ yr$^{-1}$ for Gaia20fgx during their bright state. The accretion rate of Gaia20fgx dropped by almost a factor of 10 on a time-scale of half a year. The accretion parameters of both stars were found to be similar to those of classical T Tauri stars, lower than those of young eruptive stars. However, the amplitude and time-scale of these brightenings place these stars to a region of the parameter space, which is rarely populated by young stars. This suggests a new class of young stars, which produce outbursts on a time-scale similar to young eruptive stars, but with smaller amplitudes.
