Asymmetries and Circumstellar Interaction in the Type II SN 2024bch

Asymmetries and Circumstellar Interaction in the Type II SN 2024bch

We present a comprehensive multi-epoch photometric and spectroscopic study of SN 2024bch, a nearby (19.9 Mpc) Type II supernova (SN) with prominent early high-ionization emission lines. Optical spectra from 2.8 days after the estimated explosion reveal narrow lines of H  i , He  ii , C  iv , and N ...

Full description

Saved in:
Bibliographic Details
Main Authors: Jennifer E. Andrews, Manisha Shrestha, K. Azalee Bostroem, Yize Dong, Jeniveve Pearson, M. M. Fausnaugh, David J. Sand, S. Valenti, Aravind P. Ravi, Emily Hoang, Griffin Hosseinzadeh, Ilya Ilyin, Daryl Janzen, M. J. Lundquist, Nicolás Meza, Nathan Smith, Saurabh W. Jha, Moira Andrews, Joseph Farah, Estefania Padilla Gonzalez, D. Andrew Howell, Curtis McCully, Megan Newsome, Craig Pellegrino, Giacomo Terreran, Patrick Wiggins, Brian Hsu, Collin T. Christy, Noah Franz, Xiaofeng Wang, Jialian Liu, Liyang Chen
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal
Subjects:
Core-collapse supernovae
Type II supernovae
Stellar mass loss
Red supergiant stars
Circumstellar matter
Online Access:https://doi.org/10.3847/1538-4357/ada555
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:We present a comprehensive multi-epoch photometric and spectroscopic study of SN 2024bch, a nearby (19.9 Mpc) Type II supernova (SN) with prominent early high-ionization emission lines. Optical spectra from 2.8 days after the estimated explosion reveal narrow lines of H  i , He  ii , C  iv , and N  iv that disappear by day 6. High-cadence photometry from the ground and Transiting Exoplanet Survey Satellite show that the SN brightened quickly and reached a peak M _V  ~ −17.8 mag within a week of explosion, and late-time photometry suggests a ^56 Ni mass of 0.050 M _⊙ . High-resolution spectra from days 7.9 and 43 trace the unshocked circumstellar medium (CSM) and indicate a wind velocity of 30–40 km s ^−1 , a value consistent with a red supergiant (RSG) progenitor. Comparisons between models and the early spectra suggest a pre-SN mass-loss rate of $\dot{M}\,\unicode{x0007E}\,1{0}^{-3}\unicode{8210}1{0}^{-2}\,{M}_{\odot }\,{\mathrm{yr}}^{-1}$ , which is too high to be explained by quiescent mass loss from RSGs, but is consistent with some recent measurements of similar SNe. Persistent blueshifted H  i and [O  i ] emission lines seen in the optical and near-IR spectra could be produced by asymmetries in the SN ejecta, while the multicomponent H α may indicate continued interaction with an asymmetric CSM well into the nebular phase. SN 2024bch provides another clue to the complex environments and mass-loss histories around massive stars.
ISSN:1538-4357

Similar Items