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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - SN 2022joj: A Peculiar Type Ia Supernova Possibly Driven by an Asymmetric Helium-shell Double Detonation
AU - Liu, Chang
AU - Miller, Adam
AU - Boos, Samuel
AU - Shen, Ken J.
AU - Townsley, Dean M.
AU - Schulze, Steve
AU - Harvey, Luke
AU - Maguire, Kate
AU - Johansson, Joel
AU - Brink, Thomas G.
AU - Burgaz, Umut
AU - Dimitriadis, Georgios
AU - Filippenko, Alexei
AU - Hall, Saarah
AU - Hinds, K-Ryan
AU - Hoffman, Andrew
AU - Karambelkar, Viraj
AU - Kilpatrick, Charles
AU - Perley, Daniel
AU - Pichay, Neil
AU - Sears, Huei
AU - Sollerman, Jesper
AU - Stein, Robert
AU - Terwel, Jacco
AU - Zheng, Weikang
AU - Graham, Matthew J.
AU - Kasliwal, Mansi
AU - Lacroix, Leander
AU - Purdum, Josiah
AU - Rusholme, Benjamin
AU - Wold, Avery
PY - 2023/12/1
Y1 - 2023/12/1
N2 - We present observations of SN 2022joj, a peculiar Type Ia supernova discovered by the Zwicky Transient Facility. SN 2022joj exhibits an unusually red g ZTF − r ZTF color at early times and a rapid blueward evolution afterward. Around maximum brightness, SN 2022joj shows a high luminosity ( M g ZTF , max ≃ − 19.7 mag), a blue broadband color (g ZTF − r ZTF ≃ −0.2 mag), and shallow Si ii absorption lines, consistent with those of overluminous, SN 1991T-like events. The maximum-light spectrum also shows prominent absorption around 4200 Å, which resembles the Ti ii features in subluminous, SN 1991bg-like events. Despite the blue optical-band colors, SN 2022joj exhibits extremely red ultraviolet minus optical colors at maximum luminosity (u − v ≃ 0.6 mag and uvw1 − v ≃ 2.5 mag), suggesting a suppression of flux at ∼2500-4000 Å. Strong C ii lines are also detected at peak. We show that these unusual spectroscopic properties are broadly consistent with the helium-shell double detonation of a sub-Chandrasekhar mass (M ≃ 1 M ⊙) carbon/oxygen white dwarf from a relatively massive helium shell (M s ≃ 0.04-0.1 M ⊙), if observed along a line of sight roughly opposite to where the shell initially detonates. None of the existing models could quantitatively explain all the peculiarities observed in SN 2022joj. The low flux ratio of [Ni ii] λ7378 to [Fe ii] λ7155 emission in the late-time nebular spectra indicates a low yield of stable Ni isotopes, favoring a sub-Chandrasekhar mass progenitor. The significant blueshift measured in the [Fe ii] λ7155 line is also consistent with an asymmetric chemical distribution in the ejecta, as is predicted in double-detonation models.
AB - We present observations of SN 2022joj, a peculiar Type Ia supernova discovered by the Zwicky Transient Facility. SN 2022joj exhibits an unusually red g ZTF − r ZTF color at early times and a rapid blueward evolution afterward. Around maximum brightness, SN 2022joj shows a high luminosity ( M g ZTF , max ≃ − 19.7 mag), a blue broadband color (g ZTF − r ZTF ≃ −0.2 mag), and shallow Si ii absorption lines, consistent with those of overluminous, SN 1991T-like events. The maximum-light spectrum also shows prominent absorption around 4200 Å, which resembles the Ti ii features in subluminous, SN 1991bg-like events. Despite the blue optical-band colors, SN 2022joj exhibits extremely red ultraviolet minus optical colors at maximum luminosity (u − v ≃ 0.6 mag and uvw1 − v ≃ 2.5 mag), suggesting a suppression of flux at ∼2500-4000 Å. Strong C ii lines are also detected at peak. We show that these unusual spectroscopic properties are broadly consistent with the helium-shell double detonation of a sub-Chandrasekhar mass (M ≃ 1 M ⊙) carbon/oxygen white dwarf from a relatively massive helium shell (M s ≃ 0.04-0.1 M ⊙), if observed along a line of sight roughly opposite to where the shell initially detonates. None of the existing models could quantitatively explain all the peculiarities observed in SN 2022joj. The low flux ratio of [Ni ii] λ7378 to [Fe ii] λ7155 emission in the late-time nebular spectra indicates a low yield of stable Ni isotopes, favoring a sub-Chandrasekhar mass progenitor. The significant blueshift measured in the [Fe ii] λ7155 line is also consistent with an asymmetric chemical distribution in the ejecta, as is predicted in double-detonation models.
U2 - 10.3847/1538-4357/acffc9
DO - 10.3847/1538-4357/acffc9
M3 - Journal article
VL - 958
JO - The Astrophysical Journal
JF - The Astrophysical Journal
SN - 0004-637X
IS - 2
M1 - 178
ER -