Published March 1, 2017 | Version v1
Journal article

Broad-lined Supernova 2016coi with a Helium Envelope

  • 1. Department of Physics, Faculty of Science and Engineering, Konan University, Okamoto, Kobe, Hyogo 658-8501 (Japan)
  • 2. Department of Physical Science, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima 739-8526 (Japan)
  • 3. National Astronomical Observatory of Japan, National Institutes of Natural Sciences, Osawa, Mitaka, Tokyo 181-8588 (Japan)
  • 4. Department of Astronomy, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502 (Japan)
  • 5. Nishi-Harima Astronomical Observatory, Center for Astronomy, University of Hyogo, 407-2 Nishigaichi, Sayo-cho, Sayo, Hyogo 679-5313 (Japan)
  • 6. Ishigakijima Astronomical Observatory, National Astronomical Observatory of Japan, National Institutes of Natural Sciences, 1024-1 Arakawa, Ishigaki, Okinawa 907-0024 (Japan)
  • 7. Institute of Astronomy, Graduate School of Science, The University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan)
  • 8. Department of Cosmosciences, Graduate School of Science, Hokkaido University, Kita 10 Nishi8, Kita-ku, Sapporo 060-0810 (Japan)
  • 9. Nobeyama Radio Observatory, National Astronomical Observatory of Japan, National Institutes of Natural Sciences, 462-2 Nobeyama, Minamimaki, Minamisaku, Nagano 384-1305 (Japan)
  • 10. Department of Astrophysics, Nagoya University, Chikusa-ku, Nagoya 464-8602 (Japan)
  • 11. Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima 890-0065 (Japan)
  • 12. Gunma Astronomical Observatory, Takayama, Gunma 377-0702 (Japan)

Description

We present the early-phase spectra and the light curves of the broad-lined (BL) supernova (SN) 2016coi from t = 7 to 67 days after the estimated explosion date. This SN was initially reported as a BL Type SN Ic (SN Ic-BL). However, we found that spectra up to t = 12 days exhibited the He i λ 5876, λ 6678, and λ 7065 absorption lines. We show that the smoothed and blueshifted spectra of normal SNe Ib are remarkably similar to the observed spectrum of SN 2016coi. The line velocities of SN 2016coi were similar to those of SNe Ic-BL and significantly faster than those of SNe Ib. Analyses of the line velocity and light curve suggest that the kinetic energy and the total ejecta mass of SN 2016coi are similar to those of SNe Ic-BL. Together with BL SNe 2009bb and 2012ap, for which the detection of He i was also reported, these SNe could be transitional objects between SNe Ic-BL and SNe Ib, and be classified as BL Type "Ib" SNe (SNe "Ib"-BL). Our work demonstrates the diversity of the outermost layer in BL SNe, which should be related to the variety of the evolutionary paths.

Availability note (English)

Available from http://dx.doi.org/10.3847/1538-4357/aa5f57

Additional details

Identifiers

Publishing Information

Journal Title
Astrophysical Journal
Journal Volume
837
Journal Issue
1
Journal Page Range
[8 p.]
ISSN
0004-637X
CODEN
ASJOAB

INIS

Country of Publication
United States
Country of Input or Organization
International Atomic Energy Agency (IAEA)
INIS RN
49006828
Subject category
S79: ASTROPHYSICS, COSMOLOGY AND ASTRONOMY;
Descriptors DEI
ABSORPTION; DETECTION; EXPLOSIONS; HELIUM; KINETIC ENERGY; MASS; SPECTRA; SUPERNOVAE; TYPE I SUPERNOVAE; VELOCITY; VISIBLE RADIATION
Descriptors DEC
BINARY STARS; ELECTROMAGNETIC RADIATION; ELEMENTS; ENERGY; ERUPTIVE VARIABLE STARS; FLUIDS; GASES; NONMETALS; RADIATIONS; RARE GASES; SORPTION; STARS; SUPERNOVAE; VARIABLE STARS