_version_ 1866912671916359680
author Chen, Liyang
Wang, Xiaofeng
Wu, Qinyu
Andrews, Moira
Farah, Joseph
Ochner, Paolo
Reguitti, Andrea
Brink, Thomas G.
Zhang, Jujia
Song, Cuiying
Liu, Jialian
Filippenko, Alexei V.
Sand, David J.
Albanese, Irene
Alexander, Kate D.
Andrews, Jennifer
Bostroem, K. Azalee
Cai, Yongzhi
Christy, Collin
Esamdin, Ali
Farina, Andrea
Franz, Noah
Howell, D. Andrew
Hsu, Brian
Hu, Maokai
Iskandar, Abdusamatjan
Li, Liping
Li, Gaici
Li, Dongyue
Li, Wenxiong
Liu, Jinzhong
McCully, Curtis
Newsome, Megan
Ni, Yuan Qi
Pastorello, Andrea
Gonzalez, Estefania Padilla
Pearson, Jeniveve
Peng, Haowei
Ransome, Conor
Shrestha, Manisha
Smith, Nathan
Subrayan, Bhagya
Terreran, Giacomo
Valerin, Giorgio
Vinkó, J.
Vasylyev, Sergiy S.
Wang, Letian
Wang, Zhenyu
Wang, Hao
Wheeler, J. Craig
Wynn, Kathryn
Xiang, Danfeng
Yan, Shengyu
Yuan, Weimin
Zhang, Juan
Zheng, WeiKang
Zhang, Yu
author_facet Chen, Liyang
Wang, Xiaofeng
Wu, Qinyu
Andrews, Moira
Farah, Joseph
Ochner, Paolo
Reguitti, Andrea
Brink, Thomas G.
Zhang, Jujia
Song, Cuiying
Liu, Jialian
Filippenko, Alexei V.
Sand, David J.
Albanese, Irene
Alexander, Kate D.
Andrews, Jennifer
Bostroem, K. Azalee
Cai, Yongzhi
Christy, Collin
Esamdin, Ali
Farina, Andrea
Franz, Noah
Howell, D. Andrew
Hsu, Brian
Hu, Maokai
Iskandar, Abdusamatjan
Li, Liping
Li, Gaici
Li, Dongyue
Li, Wenxiong
Liu, Jinzhong
McCully, Curtis
Newsome, Megan
Ni, Yuan Qi
Pastorello, Andrea
Gonzalez, Estefania Padilla
Pearson, Jeniveve
Peng, Haowei
Ransome, Conor
Shrestha, Manisha
Smith, Nathan
Subrayan, Bhagya
Terreran, Giacomo
Valerin, Giorgio
Vinkó, J.
Vasylyev, Sergiy S.
Wang, Letian
Wang, Zhenyu
Wang, Hao
Wheeler, J. Craig
Wynn, Kathryn
Xiang, Danfeng
Yan, Shengyu
Yuan, Weimin
Zhang, Juan
Zheng, WeiKang
Zhang, Yu
contents We present optical, ultraviolet, and X-ray observations of supernova (SN) 2024iss, a Type IIb SN that shows a prominent double-peaked light curve. We modeled the first peak with a semianalytical shock-cooling model and the X-ray emission with a free-free model. We compare the envelope radius and mass-loss rate with other Type IIb SNe to explore the relationships between the progenitor envelope and the circumstellar material (CSM). The shock-cooling peak in the $V$-band light curve reached $M_V = -17.33\pm 0.26$mag, while the $^{56}$Ni-powered second peak attained $M_V = -17.43\pm 0.26$mag. Early spectra show an photospheric velocity of $\sim19,400\,km\,s^{-1}$ at 3.82days from the H$α$ P~Cygni profile. The Balmer lines persist at least +87 days after the explosion, characterizing hydrogen-rich ejecta. Modeling the first light-curve peak suggests an extended envelope with a mass of $0.11\pm0.04\,M_{\odot}$ and a radius of $244\pm43~R_{\odot}$. Fitting the second light-curve peak with an Arnett-like model indicates a typical $^{56}$Ni mass of $ 0.117\pm0.013~M_{\odot}$ and a relatively low ejecta mass of $1.272\pm0.343\,M_{\odot}$. X-ray observations reveal bright thermal bremsstrahlung emission and indicate a mass-loss rate of $1.6\times10^{-5}\ M_{\odot} \ \rm{yr}^{-1}$. SN 2024iss occupies a transitional position between the two subclasses of extended (eIIb) and compact (cIIb) Type IIb SNe. Its envelope radius and pre-explosion mass-loss rate appear to be correlated as theoretically predicted. The observational properties of SN 2024iss are compatible with a binary interaction scenario being the dominant mechanism for envelope stripping. Furthermore, the low column density of neutral hydrogen suggests a compact CSM with an outer radius of $\lesssim1.3\times10^{14}$ cm, indicating that the progenitor star experienced eruptive mass loss within $\sim4\,yr$ of its terminal explosion.
format Preprint
id arxiv_https___arxiv_org_abs_2510_22997
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle SN 2024iss: A Double-peaked Type IIb Supernova with Evidence of Circumstellar Interaction
Chen, Liyang
Wang, Xiaofeng
Wu, Qinyu
Andrews, Moira
Farah, Joseph
Ochner, Paolo
Reguitti, Andrea
Brink, Thomas G.
Zhang, Jujia
Song, Cuiying
Liu, Jialian
Filippenko, Alexei V.
Sand, David J.
Albanese, Irene
Alexander, Kate D.
Andrews, Jennifer
Bostroem, K. Azalee
Cai, Yongzhi
Christy, Collin
Esamdin, Ali
Farina, Andrea
Franz, Noah
Howell, D. Andrew
Hsu, Brian
Hu, Maokai
Iskandar, Abdusamatjan
Li, Liping
Li, Gaici
Li, Dongyue
Li, Wenxiong
Liu, Jinzhong
McCully, Curtis
Newsome, Megan
Ni, Yuan Qi
Pastorello, Andrea
Gonzalez, Estefania Padilla
Pearson, Jeniveve
Peng, Haowei
Ransome, Conor
Shrestha, Manisha
Smith, Nathan
Subrayan, Bhagya
Terreran, Giacomo
Valerin, Giorgio
Vinkó, J.
Vasylyev, Sergiy S.
Wang, Letian
Wang, Zhenyu
Wang, Hao
Wheeler, J. Craig
Wynn, Kathryn
Xiang, Danfeng
Yan, Shengyu
Yuan, Weimin
Zhang, Juan
Zheng, WeiKang
Zhang, Yu
High Energy Astrophysical Phenomena
Solar and Stellar Astrophysics
We present optical, ultraviolet, and X-ray observations of supernova (SN) 2024iss, a Type IIb SN that shows a prominent double-peaked light curve. We modeled the first peak with a semianalytical shock-cooling model and the X-ray emission with a free-free model. We compare the envelope radius and mass-loss rate with other Type IIb SNe to explore the relationships between the progenitor envelope and the circumstellar material (CSM). The shock-cooling peak in the $V$-band light curve reached $M_V = -17.33\pm 0.26$mag, while the $^{56}$Ni-powered second peak attained $M_V = -17.43\pm 0.26$mag. Early spectra show an photospheric velocity of $\sim19,400\,km\,s^{-1}$ at 3.82days from the H$α$ P~Cygni profile. The Balmer lines persist at least +87 days after the explosion, characterizing hydrogen-rich ejecta. Modeling the first light-curve peak suggests an extended envelope with a mass of $0.11\pm0.04\,M_{\odot}$ and a radius of $244\pm43~R_{\odot}$. Fitting the second light-curve peak with an Arnett-like model indicates a typical $^{56}$Ni mass of $ 0.117\pm0.013~M_{\odot}$ and a relatively low ejecta mass of $1.272\pm0.343\,M_{\odot}$. X-ray observations reveal bright thermal bremsstrahlung emission and indicate a mass-loss rate of $1.6\times10^{-5}\ M_{\odot} \ \rm{yr}^{-1}$. SN 2024iss occupies a transitional position between the two subclasses of extended (eIIb) and compact (cIIb) Type IIb SNe. Its envelope radius and pre-explosion mass-loss rate appear to be correlated as theoretically predicted. The observational properties of SN 2024iss are compatible with a binary interaction scenario being the dominant mechanism for envelope stripping. Furthermore, the low column density of neutral hydrogen suggests a compact CSM with an outer radius of $\lesssim1.3\times10^{14}$ cm, indicating that the progenitor star experienced eruptive mass loss within $\sim4\,yr$ of its terminal explosion.
title SN 2024iss: A Double-peaked Type IIb Supernova with Evidence of Circumstellar Interaction
topic High Energy Astrophysical Phenomena
Solar and Stellar Astrophysics
url https://arxiv.org/abs/2510.22997