SN 2017ens: The Metamorphosis of a Luminous Broadlined Type Ic Supernova into an SN IIn
SN 2017ens: The Metamorphosis of a Luminous Broadlined Type Ic Supernova into an SN IIn
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DOI：
10.3847/2041-8213/aaeb2e
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发表时间：
2018-08
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通讯作者：
Ting-Wan Chen;C. Inserra;M. Fraser;T. Moriya;P. Schady;T. Schweyer;A. Filippenko;D. Perley;A. Ruiter;A. Ruiter;I. Seitenzahl;I. Seitenzahl;J. Sollerman;F. Taddia;Joseph P. Anderson;R. Foley;A. Jerkstrand;C. Ngeow;Yen-Chen Pan;A. Pastorello;S. Points;S. Smartt;K. Smith;S. Taubenberger;S. Taubenberger;P. Wiseman;D. Young;S. Benetti;M. Berton;M. Berton;F. Bufano;P. Clark;M. Valle;M. Valle;L. Galbany;A. Gal-yam;M. Gromadzki;C. Gutiérrez;A. Heinze;E. Kankare;C. Kilpatrick;H. Kuncarayakti;G. Leloudas;Zhong-Yi Lin;K. Maguire;P. Mazzali;O. McBrien;S. Prentice;A. Rau;A. Rest;A. Rest;M. Siebert;B. Stalder;J. Tonry;P. Yu
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作者：
Ting-Wan Chen;C. Inserra;M. Fraser;T. Moriya;P. Schady;T. Schweyer;A. Filippenko;D. Perley;A. Ruiter;A. Ruiter;I. Seitenzahl;I. Seitenzahl;J. Sollerman;F. Taddia;Joseph P. Anderson;R. Foley;A. Jerkstrand;C. Ngeow;Yen-Chen Pan;A. Pastorello;S. Points;S. Smartt;K. Smith;S. Taubenberger;S. Taubenberger;P. Wiseman;D. Young;S. Benetti;M. Berton;M. Berton;F. Bufano;P. Clark;M. Valle;M. Valle;L. Galbany;A. Gal-yam;M. Gromadzki;C. Gutiérrez;A. Heinze;E. Kankare;C. Kilpatrick;H. Kuncarayakti;G. Leloudas;Zhong-Yi Lin;K. Maguire;P. Mazzali;O. McBrien;S. Prentice;A. Rau;A. Rest;A. Rest;M. Siebert;B. Stalder;J. Tonry;P. Yu
我们目前对超新星（SN）2017 ens的观测，该超新星是由ATLAS巡天发现的，并通过GREAT计划被确定为热蓝色天体。红移z = 0.1086意味着峰值亮度Mg = −21.1等，将该天体置于超亮超新星的范围内。我们观察到一个戏剧性的光谱演化，从最初的蓝色和无特征，到后来发展出类似于宽线Ic型SN 1998 bw的特征，最后显示出2000 km s−1宽的Hα和Hβ发射。相对窄的巴耳末发射（让人想起SN IIn）始终存在。我们还检测到日冕线，表明一个密集的星周介质。我们根据P-Cygni剖面将祖先风速限制在150 -60 km s−1，这比沃尔夫-拉叶星的风速慢得多。这可能意味着这颗恒星的前身经过了一个明亮的蓝色变星相，或者这颗恒星风是来自一颗伴星红超巨星星星。在后期，我们看到了2000 km/s−1宽的Hα辐射在高光度（103 × 1040 erg/s−1）下持续了至少100天，这可能表明了高速下额外的质量损失，可能是由脉动对不稳定性喷射出来的。
We present observations of supernova (SN) 2017ens, discovered by the ATLAS survey and identified as a hot blue object through the GREAT program. The redshift z = 0.1086 implies a peak brightness of Mg = −21.1 mag, placing the object within the regime of superluminous supernovae. We observe a dramatic spectral evolution, from initially being blue and featureless, to later developing features similar to those of the broadlined Type Ic SN 1998bw, and finally showing ∼2000 km s−1 wide Hα and Hβ emission. Relatively narrow Balmer emission (reminiscent of a SN IIn) is present at all times. We also detect coronal lines, indicative of a dense circumstellar medium. We constrain the progenitor wind velocity to ∼50–60 km s−1 based on P-Cygni profiles, which is far slower than those present in Wolf–Rayet stars. This may suggest that the progenitor passed through a luminous blue variable phase, or that the wind is instead from a binary companion red supergiant star. At late times we see the ∼2000 km s−1 wide Hα emission persisting at high luminosity (∼3 × 1040 erg s−1) for at least 100 day, perhaps indicative of additional mass loss at high velocities that could have been ejected by a pulsational pair instability.