1. SN 2022oqm: A Bright and Multipeaked Calcium-rich Transient
- Author
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S. Karthik Yadavalli, V. Ashley Villar, Luca Izzo, Yossef Zenati, Ryan J. Foley, J. Craig Wheeler, Charlotte R. Angus, Dominik Bánhidi, Katie Auchettl, Barna Imre Bíró, Attila Bódi, Zsófia Bodola, Thomas de Boer, Kenneth C. Chambers, Ryan Chornock, David A. Coulter, István Csányi, Borbála Cseh, Srujan Dandu, Kyle W. Davis, Connor Braden Dickinson, Diego Farias, Joseph Farah, Christa Gall, Hua Gao, D. Andrew Howell, Wynn V. Jacobson-Galan, Nandita Khetan, Charles D. Kilpatrick, Réka Könyves-Tóth, Levente Kriskovics, Natalie LeBaron, Kayla Loertscher, X. K. Le Saux, Raffaella Margutti, Eugene A. Magnier, Curtis McCully, Peter McGill, Hao-Yu Miao, Megan Newsome, Estefania Padilla Gonzalez, András Pál, Boróka H. Pál, Yen-Chen Pan, Collin A. Politsch, Conor L. Ransome, Enrico Ramirez-Ruiz, Armin Rest, Sofia Rest, Olivia Robinson, Huei Sears, Jackson Scheer, Ádám Sódor, Jonathan Swift, Péter Székely, Róbert Szakáts, Tamás Szalai, Kirsty Taggart, Giacomo Terreran, Padma Venkatraman, József Vinkó, Grace Yang, and Henry Zhou
- Subjects
White dwarf stars ,Binary stars ,Supernovae ,Astrophysics ,QB460-466 - Abstract
We present the photometric and spectroscopic evolution of SN 2022oqm, a nearby multipeaked hydrogen- and helium-weak calcium-rich transient (CaRT). SN 2022oqm was detected 13.1 kpc from its host galaxy, the face-on spiral galaxy NGC 5875. Extensive spectroscopic coverage reveals an early hot ( T ≥ 40,000 K) continuum and carbon features observed ∼1 day after discovery, SN Ic-like photospheric-phase spectra, and strong forbidden calcium emission starting 38 days after discovery. SN 2022oqm has a relatively high peak luminosity ( M _B = −17 mag) for CaRTs, making it an outlier in the population. We determine that three power sources are necessary to explain the light curve (LC), with each corresponding to a distinct peak. The first peak is powered by an expanding blackbody with a power-law luminosity, suggesting shock cooling by circumstellar material (CSM). Subsequent LC evolution is powered by a double radioactive decay model, consistent with two sources of photons diffusing through optically thick ejecta. From the LC, we derive an ejecta mass and ^56 Ni mass of ∼0.6 M _⊙ and ∼0.09 M _⊙ . Spectroscopic modeling ∼0.6 M _⊙ of ejecta, and with well-mixed Fe-peak elements throughout. We discuss several physical origins for SN 2022oqm and find either a surprisingly massive white dwarf progenitor or a peculiar stripped envelope model could explain SN 2022oqm. A stripped envelope explosion inside a dense, hydrogen- and helium-poor CSM, akin to SNe Icn, but with a large 56Ni mass and small CSM mass could explain SN 2022oqm. Alternatively, helium detonation on an unexpectedly massive white dwarf could also explain SN 2022oqm.
- Published
- 2024
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