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

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 {sub ☉} 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 amountmore » 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.« less

Authors:
; ; ;  [1]; ;  [2]; ;  [3];  [4];  [5]; ; ;  [6];  [7]
  1. Las Cumbres Observatory, 6740 Cortona Drive, Suite 102, Goleta, CA 93117-5575 (United States)
  2. Department of Astronomy/Steward Observatory, 933 North Cherry Avenue, Room N204, Tucson, AZ 85721-0065 (United States)
  3. Department of Physics, University of California, 1 Shields Avenue, Davis, CA 95616-5270 (United States)
  4. Mitchell Institute for Fundamental Physics and Astronomy, Texas A and M University, College Station, TX 77843-4242 (United States)
  5. Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720-8169 (United States)
  6. Department of Physics, Florida State University, 77 Chieftain Way, Tallahassee, FL 32306-4350 (United States)
  7. Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark)
Publication Date:
OSTI Identifier:
22654411
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 845; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION; CARBON; DISTRIBUTION; EXPLOSIONS; INTERACTIONS; NICKEL; SPECTRA; SUPERNOVAE; ULTRAVIOLET RADIATION; VISIBLE RADIATION; WHITE DWARF STARS

Citation Formats

Hosseinzadeh, Griffin, Howell, D. Andrew, McCully, Curtis, Arcavi, Iair, Sand, David J., Tartaglia, Leonardo, Valenti, Stefano, Bostroem, K. Azalee, Brown, Peter, Kasen, Daniel, Hsiao, Eric Y., Davis, Scott, Shahbandeh, Melissa, and Stritzinger, Maximilian D., E-mail: griffin@lco.global. Early Blue Excess from the Type Ia Supernova 2017cbv and Implications for Its Progenitor. United States: N. p., 2017. Web. doi:10.3847/2041-8213/AA8402.
Hosseinzadeh, Griffin, Howell, D. Andrew, McCully, Curtis, Arcavi, Iair, Sand, David J., Tartaglia, Leonardo, Valenti, Stefano, Bostroem, K. Azalee, Brown, Peter, Kasen, Daniel, Hsiao, Eric Y., Davis, Scott, Shahbandeh, Melissa, & Stritzinger, Maximilian D., E-mail: griffin@lco.global. Early Blue Excess from the Type Ia Supernova 2017cbv and Implications for Its Progenitor. United States. doi:10.3847/2041-8213/AA8402.
Hosseinzadeh, Griffin, Howell, D. Andrew, McCully, Curtis, Arcavi, Iair, Sand, David J., Tartaglia, Leonardo, Valenti, Stefano, Bostroem, K. Azalee, Brown, Peter, Kasen, Daniel, Hsiao, Eric Y., Davis, Scott, Shahbandeh, Melissa, and Stritzinger, Maximilian D., E-mail: griffin@lco.global. Sun . "Early Blue Excess from the Type Ia Supernova 2017cbv and Implications for Its Progenitor". United States. doi:10.3847/2041-8213/AA8402.
@article{osti_22654411,
title = {Early Blue Excess from the Type Ia Supernova 2017cbv and Implications for Its Progenitor},
author = {Hosseinzadeh, Griffin and Howell, D. Andrew and McCully, Curtis and Arcavi, Iair and Sand, David J. and Tartaglia, Leonardo and Valenti, Stefano and Bostroem, K. Azalee and Brown, Peter and Kasen, Daniel and Hsiao, Eric Y. and Davis, Scott and Shahbandeh, Melissa and Stritzinger, Maximilian D., E-mail: griffin@lco.global},
abstractNote = {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 {sub ☉} 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.},
doi = {10.3847/2041-8213/AA8402},
journal = {Astrophysical Journal Letters},
number = 2,
volume = 845,
place = {United States},
year = {Sun Aug 20 00:00:00 EDT 2017},
month = {Sun Aug 20 00:00:00 EDT 2017}
}