2014/07/24 by Gastón Folatelli, G. Folatelli, Melina C. Bersten +44 · 2 citations
Physics and Astronomy · #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Astrophysics and Cosmic Phenomena #Ejecta #Gamma-ray bursts and supernovae #Light curve #Pair-instability supernova #Physics #Supernova #Type (biology) #astro-ph.CO #astro-ph.HE
paper · pdf · doi:10.1088/0004-637x/792/1/7
published as 2014 ApJ 792 7 · 29 pages, 24 figures, 10 tables. Accepted for publication at ApJ on July 4, 2014
arxiv created 2014/07/24 · openalex publication_date 2014/08/08 · arxiv updated 2015/02/05 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present extensive optical and near-infrared photometric and spectroscopic observations of the stripped-envelope supernova SN 2010as. Spectroscopic peculiarities such as initially weak helium features and low expansion velocities with a nearly flat evolution place this object in the small family of events previously identified as transitional Type Ib/c supernovae (SNe). There is ubiquitous evidence of hydrogen, albeit weak, in this family of SNe, indicating that they are in fact a peculiar kind of Type IIb SNe that we name "flat-velocity Type IIb. The flat-velocity evolution—which occurs at different levels between 6000 and 8000 km s −1 for different SNe—suggests the presence of a dense shell in the ejecta. Despite the spectroscopic similarities, these objects show surprisingly diverse luminosities. We discuss the possible physical or geometrical unification picture for such diversity. Using archival Hubble Space Telescope images, we associate SN 2010as with a massive cluster and derive a progenitor age of ≈6 Myr, assuming a single star-formation burst, which is compatible with a Wolf–Rayet progenitor. Our hydrodynamical modeling, on the contrary, indicates that the pre-explosion mass was relatively low, ≈4 M ☉ . The seeming contradiction between a young age and low pre-SN mass may be solved by a massive interacting binary progenitor.