SN 2007od: A TYPE IIP SUPERNOVA WITH CIRCUMSTELLAR INTERACTION
SN 2007od: A TYPE IIP SUPERNOVA WITH CIRCUMSTELLAR INTERACTION
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DOI：
10.1088/0004-637x/715/1/541
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发表时间：
2010-04
期刊：
影响因子：
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通讯作者：
J. Andrews;J. Gallagher;G. Clayton;B. Sugerman;J. Chatelain;J. Clem;D. Welch;M. Barlow;B. Ercolano;J. Fabbri;R. Wesson;M. Meixner
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文献类型：
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作者：
J. Andrews;J. Gallagher;G. Clayton;B. Sugerman;J. Chatelain;J. Clem;D. Welch;M. Barlow;B. Ercolano;J. Fabbri;R. Wesson;M. Meixner
SN 2007od展现了IIP型超新星（SN）中罕见的特徴。光学V波段光度测定显示，在平台期和星云期之间，SN 2007od的亮度有一个非常陡峭的下降，亮度为4.5等，可能是因为SN 2007od含有低质量的56 Ni。光学光谱显示，从正常的IIP型与广泛的H α发射，到一个复杂的，四个组件的H α发射轮廓表现出不对称的尘埃消光后，232天的演变。这与SN 1998 S的I型光谱演化相似，但SN 2007 od没有早期窄（约200 km s − 1）的H α成分。在这两个SNe中，中等宽度的H α发射分量被认为是在喷出物与其星周介质（CSM）之间的相互作用中产生的。SN 2007od还显示了由于新尘埃而产生的中红外过量。H α分布的演化和中红外线过剩的存在提供了强有力的证据，证明SN 2007od在第232天之前形成了新的尘埃。后期的观测揭示了可见光曲线的平坦化。这种平坦化强烈表明存在光回波，这可能解释了后期观察到的大部分广泛的潜在H α分量。我们相信多峰H α辐射与喷出物与环或环面（内部成分在± 1500 km s − 1）和CSM环平面外的单个团或云的环物质（外部成分在− 5000 km s − 1）的相互作用一致。新尘埃最有可能形成的位置是在膨胀的喷出物和它的CSM之间的相互作用所产生的冷的致密壳层中。对SN 2007 od尘埃辐射的蒙特卡罗辐射传输模型表明，有多达104 × 10 − 4 M的新尘埃形成。这与其他核心坍缩超新星如SNe 1999em、2004et和2006jc形成的尘埃量相似。
SN 2007od exhibits characteristics that have rarely been seen in a Type IIP supernova (SN). Optical V-band photometry reveals a very steep brightness decline between the plateau and nebular phases of ∼4.5 mag, likely due to SN 2007od containing a low mass of 56Ni. The optical spectra show an evolution from normal Type IIP with broad Hα emission, to a complex, four-component Hα emission profile exhibiting asymmetries caused by dust extinction after day 232. This is similar to the spectral evolution of the Type IIn SN 1998S, although no early-time narrow (∼200 km s−1) Hα component was present in SN 2007od. In both SNe, the intermediate-width Hα emission components are thought to arise in the interaction between the ejecta and its circumstellar medium (CSM). SN 2007od also shows a mid-infrared excess due to new dust. The evolution of the Hα profile and the presence of the mid-IR excess provide strong evidence that SN 2007od formed new dust before day 232. Late-time observations reveal a flattening of the visible light curve. This flattening is a strong indication of the presence of a light echo, which likely accounts for much of the broad, underlying Hα component seen at late times. We believe that the multi-peaked Hα emission is consistent with the interaction of the ejecta with a circumstellar ring or torus (for the inner components at ±1500 km s−1) and a single blob or cloud of circumstellar material out of the plane of the CSM ring (for the outer component at −5000 km s−1). The most probable location for the formation of new dust is in the cool dense shell created by the interaction between the expanding ejecta and its CSM. Monte Carlo radiative transfer modeling of the dust emission from SN 2007od implies that up to ∼4 × 10−4 M☉ of new dust has formed. This is similar to the amounts of dust formed in other core-collapse supernovae such as SNe 1999em, 2004et, and 2006jc.