Massive stars exploding in a He-rich circumstellar medium - VII. The metamorphosis of ASASSN-15ed from a narrow line Type Ibn to a normal Type Ib Supernova

A. Pastorello, J. L. Prieto, N. Elias-Rosa, D. Bersier, G. Hosseinzadeh, A. Morales-Garoffolo, U. M. Noebauer, S. Taubenberger, L. Tomasella, C. S. Kochanek, E. Falco, U. Basu, J. F. Beacom, S. Benetti, J. Brimacombe, E. Cappellaro, A. B. Danilet, Subo Dong, J. M. Fernandez, N. GossV. Granata, A. Harutyunyan, T. W.S. Holoien, E. E.O. Ishida, S. Kiyota, G. Krannich, B. Nicholls, P. Ochner, G. Pojmański, B. J. Shappee, G. V. Simonian, K. Z. Stanek, Sumner Starrfield, D. Szczygiel, L. Tartaglia, G. Terreran, T. A. Thompson, M. Turatto, R. M. Wagner, W. S. Wiethoff, A. Wilber, P. R. Woźniak

Research output: Contribution to journalArticle

10 Scopus citations

Abstract

We present the results of the spectroscopic and photometric monitoring campaign of ASASSN- 15ed. The transient was discovered quite young by the All Sky Automated Survey for Super- Novae (ASAS-SN) survey. Amateur astronomers allowed us to sample the photometric SN evolution around maximum light,which we estimate to have occurred on JD=2457087.4±0.6 in the r band. Its apparent r-band magnitude at maximum was r = 16.91 ± 0.10, providing an absolute magnitude Mr ≈-20.04 ± 0.20, which is slightly more luminous than the typical magnitudes estimated for Type Ibn SNe. The post-peak evolution was well monitored, and the decline rate (being in most bands around 0.1 mag d-1 during the first 25 d after maximum) is marginally slower than the average decline rates of SNe Ibn during the same time interval. The object was initially classified as a Type Ibn SN because early-time spectra were characterized by a blue continuum with superimposed narrow P-Cygni lines of He I, suggesting the presence of a slowly moving (1200-1500 km s-1), He-rich circumstellar medium. Later on, broad P-Cygni He I lines became prominent. The inferred velocities, as measured from the minimum of the broad absorption components, were between 6000 and 7000 km s-1. As we attribute these broad features to the SN ejecta, this is the first time we have observed the transition of a Type Ibn SN to a Type Ib SN.

Original languageEnglish (US)
Pages (from-to)3649-3661
Number of pages13
JournalMonthly Notices of the Royal Astronomical Society
Volume453
Issue number4
DOIs
StatePublished - Jan 1 2015

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Keywords

  • Supernovae: general
  • Supernovae: individual: ASASSN-15ed
  • Supernovae: individual: SN 1991D
  • Supernovae: individual: SN 2006jc
  • Supernovae: individual: SN 2010al

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Pastorello, A., Prieto, J. L., Elias-Rosa, N., Bersier, D., Hosseinzadeh, G., Morales-Garoffolo, A., Noebauer, U. M., Taubenberger, S., Tomasella, L., Kochanek, C. S., Falco, E., Basu, U., Beacom, J. F., Benetti, S., Brimacombe, J., Cappellaro, E., Danilet, A. B., Dong, S., Fernandez, J. M., ... Woźniak, P. R. (2015). Massive stars exploding in a He-rich circumstellar medium - VII. The metamorphosis of ASASSN-15ed from a narrow line Type Ibn to a normal Type Ib Supernova. Monthly Notices of the Royal Astronomical Society, 453(4), 3649-3661. https://doi.org/10.1093/mnras/stv1812