Dissecting the Different Components of the Modest Accretion Bursts of the Very Young Protostar HOPS 373
Dissecting the Different Components of the Modest Accretion Bursts of the Very Young Protostar HOPS 373
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DOI：
10.3847/1538-4357/ac5632
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发表时间：
2022-02
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通讯作者：
Sung-yong Yoon;G. Herczeg;Jeong-Eun Lee;Ho-Gyu Lee;D. Johnstone;W. Varricatt;J. Tobin;C. C. Peña-C.-C.
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作者：
Sung-yong Yoon;G. Herczeg;Jeong-Eun Lee;Ho-Gyu Lee;D. Johnstone;W. Varricatt;J. Tobin;C. C. Peña-C.-C.
观测到的原恒星亮度变化可能很难解释。在我们的詹姆斯克拉克麦克斯韦望远镜（JCMT）瞬态监测巡天中，我们发现一个年轻的双星，HOPS 373，在850 μm处正在经历30%的亮度增加，这是由吸积率增加1.8-3.3倍引起的。最初的爆发发生在几个月内，有一个急剧的上升，然后是一个较浅的衰减。衰变后不久又出现了第二次上升，一年后光源仍然明亮。中红外辐射、阿尔马映射的小尺度CO外流和可变脉泽辐射的位置表明，这种变化与西南分量有关。近红外和NEOWISE W1和W2辐射位于沿着蓝移的CO外流，与SW分量在空间上偏移1.3 ~ 4″。UKIRT拍摄的K波段辐射图像显示，在外流边缘有一个紧凑的H2发射源，尾部追踪外流到源。W1的发射，可能是由散射光主导的，增亮了0.7等，与基于亚毫米光变曲线的预期一致。在K波段和W2的连续可变性的信号被稳定的H2发射所掩盖，如在我们的Gemini/GNIRS光谱中所看到的，并且可能被CO发射所掩盖。这些发射源的差异使红外搜索最年轻的原恒星的变异性变得复杂。
Observed changes in protostellar brightness can be complicated to interpret. In our James Clerk Maxwell Telescope (JCMT) Transient Monitoring Survey, we discovered that a young binary protostar, HOPS 373, is undergoing a modest 30% brightness increase at 850 μm, caused by a factor of 1.8–3.3 enhancement in the accretion rate. The initial burst occurred over a few months, with a sharp rise and then a shallower decay. A second rise occurred soon after the decay, and the source is still bright one year later. The mid-IR emission, the small-scale CO outflow mapped with ALMA, and the location of variable maser emission indicate that the variability is associated with the SW component. The near-IR and NEOWISE W1 and W2 emission is located along the blueshifted CO outflow, spatially offset by ∼3 to 4″ from the SW component. The K-band emission imaged by UKIRT shows a compact H2 emission source at the edge of the outflow, with a tail tracing the outflow back to the source. The W1 emission, likely dominated by scattered light, brightens by 0.7 mag, consistent with expectations based on the submillimeter light curve. The signal of continuum variability in K band and W2 is masked by stable H2 emission, as seen in our Gemini/GNIRS spectrum, and perhaps by CO emission. These differences in emission sources complicate IR searches for variability of the youngest protostars.