A population of eruptive variable protostars in VVV
C. Contreras Peña, P. W. Lucas, D. Minniti, R. Kurtev, W. Stimson, C. Navarro Molina, J. Borissova, N. Kumar, M. A. Thompson, T. Gledhill, R. Terzi, D. Froebric… 展开作者
C. Contreras Peña, P. W. Lucas, D. Minniti, R. Kurtev, W. Stimson, C. Navarro Molina, J. Borissova, N. Kumar, M. A. Thompson, T. Gledhill, R. Terzi, D. Froebrich, A. Caratti o Garatti
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Accepted for publication in MNRAS, 51 pages, 23 figures
We present the discovery of 816 high amplitude infrared variable stars ($ΔK_{\rm s} >$ 1 mag) in 119 deg$^2$ of the Galactic midplane covered by the Vista Variables in the Via Lactea (VVV) survey. Almost all are new discoveries and about 50$\%$ are YSOs. This provides further evidence that YSOs are the commonest high amplitude infrared variable stars in the Galactic plane. In the 2010-2014 time series of likely YSOs we find that the amplitude of variability increases towards younger evolutionary classes (class I and flat-spectrum sources) except on short timescales ($<$25 days) where this trend is reversed. Dividing the likely YSOs by light curve morphology, we find 106 with eruptive light curves, 45 dippers, 39 faders, 24 eclipsing binaries, 65 long-term periodic variables (P$>$100 days) and 162 short-term variables. Eruptive YSOs and faders tend to have the highest amplitudes and eruptive systems have the reddest SEDs. Follow up spectroscopy in a companion paper verifies high accretion rates in the eruptive systems. Variable extinction is disfavoured by the 2 epochs of colour data. These discoveries increase the number of eruptive variable YSOs by a factor of at least 5, most being at earlier stages of evolution than the known FUor and EXor types. We find that eruptive variability is at least an order of magnitude more common in class I YSOs than class II YSOs. Typical outburst durations are 1 to 4 years, between those of EXors and FUors. They occur in 3 to 6\% of class I YSOs over a 4 year time span.
An FUor-like Outbursting Class I Protostar in NGC 7538
China Three Gorges University（三峡大学）；National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；University of Chinese Academy of Sciences（中国科学院大学）
NGC 7538 MIR展现巨大亮度爆发和持续高亮度状态，其近红外光变曲线分为爆发前、爆发和爆发后三个阶段，揭示原恒星早期阶段类似FUor的吸积事件的重要性。
Spectral survey of a Hot core with an Eruptive Accretion in S255IR NIRS3 (SHEA): The discovery of class I and class II millimeter methanol maser transitions
该研究在爆发后原恒星 S255IR NIRS3 中首次探测到 I 类和 II 类毫米波甲醇脉泽跃迁，并通过激发图和 LTE 模型区分脉泽与热辐射，发现 I 类脉泽示踪缓慢外流激波。
