Статья

Early Blue Excess from the Type Ia Supernova 2017cbv and Implications for Its Progenitor

Griffin HosseinzadehDepartment of Physics, University of California, Santa Barbara, CA 93106-9530, USADavid SandDepartment of Astronomy/Steward Observatory, 933 North Cherry Avenue, Room N204, Tucson, AZ 85721-0065, USAStefano ValentiDepartment of Physics, University of California, 1 Shields Avenue, Davis, CA 95616-5270, USAPeter J. BrownMitchell Institute for Fundamental Physics and Astronomy, Texas A&M University, College Station, TX 77843-4242, USAD. A. HowellDepartment of Physics, University of California, Santa Barbara, CA 93106-9530, USACurtis McCullyDepartment of Physics, University of California, Santa Barbara, CA 93106-9530, USADaniel KasenDepartments of Physics and Astronomy, University of California, Berkeley, CA 94720-7300, USAIair ArcaviDepartment of Physics, University of California, Santa Barbara, CA 93106-9530, USAO. FoxDepartment of Physics, University of California, 1 Shields Avenue, Davis, CA 95616-5270, USALeonardo TartagliaDepartment of Astronomy/Steward Observatory, 933 North Cherry Avenue, Room N204, Tucson, AZ 85721-0065, USAE. Y. HsiaoDepartment of Physics, Florida State University, 77 Chieftain Way, Tallahassee, FL 32306-4350, USAScott DavisDepartment of Physics, Florida State University, 77 Chieftain Way, Tallahassee, FL 32306-4350, USAMelissa ShahbandehDepartment of Physics, Florida State University, 77 Chieftain Way, Tallahassee, FL 32306-4350, USAM. StritzingerDepartment of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark

2017en

ABI

Аннотация

Abstract We present very early, high-cadence photometric observations of the nearby Type Ia SN 2017cbv. The light curve is unique in that it has a blue bump during the first five days of observations in the U , B , and g bands, which is clearly resolved given our photometric cadence of 5.7 hr during that time span. We model the light curve as the combination of early shocking of the supernova ejecta against a nondegenerate companion star plus a standard SN Ia component. Our best-fit model suggests the presence of a subgiant star 56 R ☉ from the exploding white dwarf, although this number is highly model-dependent. While this model matches the optical light curve well, it overpredicts the observed flux in the ultraviolet bands. This may indicate that the shock is not a blackbody, perhaps because of line blanketing in the UV. Alternatively, it could point to another physical explanation for the optical blue bump, such as interaction with circumstellar material or an unusual nickel distribution. Early optical spectra of SN 2017cbv show strong carbon (C ii λ 6580) absorption up through day −13 with respect to maximum light, suggesting that the progenitor system contains a significant amount of unburned material. These early results on SN 2017cbv illustrate the power of early discovery and intense follow-up of nearby supernovae to resolve standing questions about the progenitor systems and explosion mechanisms of SNe Ia.

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Идентификаторы

DOI: 10.3847/2041-8213/aa8402

Цитирования и источники

Цитирований: 3Использованных источников: 0

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