论文标题
R Coronae Borealis星星I：Palomar Gattini IR的红外光曲线
Census of R Coronae Borealis stars I: Infrared light curves from Palomar Gattini IR
论文作者
论文摘要
我们正在以银河系的第一个系统的北极骨（RCB）恒星进行系统的系统红外（IR）人口普查，从Palomar Gattini IR（PGIR）调查的IR光曲线开始。 PGIR是30厘米$ J $ -Band望远镜，带有25度$^{2} $相机，正在测量北天天空（$δ> -28^{o} $）的18000 ver $^{2} $以2天的节奏。我们为从基于MID-IR颜色的目录中选择的922个RCB候选者提供了PGIR光曲线（Tisserand等，2020）。在这922名中，有149个有希望的RCB候选者，因为它们显示出类似于RCB恒星的脉动或下降。不是RCB恒星的大多数候选者是长期变量（LPV）或RV-Tauri星。我们确定基于颜色的标准，以更好地区分RCB恒星和LPV。作为试验光谱奔跑的一部分，我们在149名有希望的候选人中获得了26个NIR光谱，并在光谱上确认了11颗新的RCB恒星。我们在所有RCB恒星的光谱中都发现了强大的He i $λ10830$，可能起源于高速度（200-400 km-s $^{ - 1} $）在其大气中的风。这些RCB星中的9个显示$^{12} $ C $^{16} $ O和$^{12} $ C $^{18} $ o分子吸收功能，表明它们是通过白矮人合并形成的。我们在5个RCB星的光曲线中检测到准周期性脉动。周期范围在30-125天之间，可能源自这些恒星中的奇怪模式不稳定性。我们的飞行员运行结果激发了一项专门的红外光谱运动，以对所有RCB候选人进行分类。
We are undertaking the first systematic infrared (IR) census of R Coronae Borealis (RCB) stars in the Milky Way, beginning with IR light curves from the Palomar Gattini IR (PGIR) survey. PGIR is a 30 cm $J$-band telescope with a 25 deg$^{2}$ camera that is surveying 18000 deg$^{2}$ of the northern sky ($δ>-28^{o}$) at a cadence of 2 days. We present PGIR light curves for 922 RCB candidates selected from a mid-IR color-based catalog (Tisserand et al. 2020). Of these 922, 149 are promising RCB candidates as they show pulsations or declines similar to RCB stars. Majority of the candidates that are not RCB stars are either long period variables (LPVs) or RV-Tauri stars. We identify IR color-based criteria to better distinguish between RCB stars and LPVs. As part of a pilot spectroscopic run, we obtained NIR spectra for 26 out of the 149 promising candidates and spectroscopically confirm 11 new RCB stars. We detect strong He I $λ10830$ features in spectra of all RCB stars, likely originating within high velocity (200-400 km-s$^{-1}$) winds in their atmospheres. 9 of these RCB stars show $^{12}$C$^{16}$O and $^{12}$C$^{18}$O molecular absorption features, suggesting that they are formed through a white dwarf merger. We detect quasi-periodic pulsations in the light curves of 5 RCB stars. The periods range between 30-125 days and likely originate from the strange-mode instability in these stars. Our pilot run results motivate a dedicated IR spectroscopic campaign to classify all RCB candidates.
