Infrared spectroscopy of eruptive variable protostars from VVV
Infrared spectroscopy of eruptive variable protostars from VVV
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DOI：
10.1093/mnras/stw2802
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发表时间：
2016-02
影响因子：
4.8
通讯作者：
C. C. Peña-C.;P. Lucas;R. Kurtev;D. Minniti;A. C. O. Garatti;F. Marocco;M. Thompson;D. Froebrich;N. Kumar;W. Stimson;C. N. Molina;J. Borissova;T. Gledhill;R. Terzi
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文献类型：
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作者：
C. C. Peña-C.;P. Lucas;R. Kurtev;D. Minniti;A. C. O. Garatti;F. Marocco;M. Thompson;D. Froebrich;N. Kumar;W. Stimson;C. N. Molina;J. Borissova;T. Gledhill;R. Terzi
在一个同伴的工作（论文I），我们发现了大量的高度可变的年轻恒星对象（YSO）在Vista变量在通过Lactea（VVV）调查，通常具有I类或平坦的光谱能量分布和不同的光曲线类型。在这里，我们提出了红外光谱（0.9-2.5？？m）的37个变量，其中许多观察到一个明亮的状态。光谱证实，15/18源爆发光变曲线有一个高吸积率的签名，要么显示EXOR类发射功能（？v = 2 CO，Br？）和/或类FUor特征（？v = 2 CO和H_2O强吸收）。类似的功能，看到在一些长期的周期YSO和推子，但不是在勺或短期变量。样本包括一些尘埃状的Mira变星（通常以平滑的Mira光变曲线区分），两个激变变星和一颗碳星星。总的来说，我们已经增加了19个新的对象，广泛的类爆发变量YSO与情节吸积。在我们的样本中，在明亮的状态下观察到的爆发变量YSO显示出比样本其余部分更高的吸积光度。大多数的爆发变量不同，从既定的FUor和EXor子类，显示中间的爆发持续时间和混合物的光谱特性。这与最近的一些其他发现一致。由于这些以前的非典型对象现在是大多数嵌入式成员的类，我们提出了一个新的分类为他们的MNors。这个术语（发音为emnor）源自猎户座V1647，它是麦克尼尔星云的照明星星。
In a companion work (Paper I), we detected a large population of highly variable Young Stellar Objects (YSOs) in the Vista Variables in the Via Lactea (VVV) survey, typically with class I or flat spectrum spectral energy distributions and diverse light-curve types. Here we present infrared spectra (0.9–2.5??m) of 37 of these variables, many of them observed in a bright state. The spectra confirm that 15/18 sources with eruptive light curves have signatures of a high accretion rate, either showing EXor-like emission features (?v = 2 CO, Br?) and/or FUor-like features (?v = 2 CO and H2O strongly in absorption). Similar features were seen in some long-term periodic YSOs and faders but not in dippers or short-term variables. The sample includes some dusty Mira variables (typically distinguished by smooth Mira-like light curves), two cataclysmic variables and a carbon star. In total, we have added 19 new objects to the broad class of eruptive variable YSOs with episodic accretion. Eruptive variable YSOs in our sample that were observed at bright states show higher accretion luminosities than the rest of the sample. Most of the eruptive variables differ from the established FUor and EXor subclasses, showing intermediate outburst durations and a mixture of their spectroscopic characteristics. This is in line with a small number of other recent discoveries. Since these previously atypical objects are now the majority amongst embedded members of the class, we propose a new classification for them as MNors. This term (pronounced emnor) follows V1647 Ori, the illuminating star of McNeil's Nebula.