학술논문
SN 2016dsg: A Thermonuclear Explosion Involving A Thick Helium Shell
Document Type
Working Paper
Author
Dong, Yize; Valenti, Stefano; Polin, Abigail; Boyle, Aoife; Flörs, Andreas; Vogl, Christian; Kerzendorf, Wolfgang; Sand, David; Jha, Saurabh; Wyrzykowski, Lukasz; Bostroem, K.; Pearson, Jeniveve; McCully, Curtis; Andrew, Jennifer; Benettii, Stefano; Blondin, Stephane; Galbany, Lluís; Gromadzki, Mariusz; Hosseinzadeh, Griffin; Howell, D. Andrew; Inserra, Cosimo; Jencson, Jacob; Lundquist, M.; Lyman, Joseph; Magee, Mark; Maguire, Kate; Meza, Nicolas; Srivastav, Shubham; Taubenberger, Stefan; Terwel, J; Wyatt, Samuel; Young, David
Source
Subject
Language
Abstract
A thermonuclear explosion triggered by a helium-shell detonation on a carbon-oxygen white dwarf core has been predicted to have strong UV line blanketing at early times due to the iron-group elements produced during helium-shell burning. We present the photometric and spectroscopic observations of SN 2016dsg, a sub-luminous peculiar Type I SN consistent with a thermonuclear explosion involving a thick He shell. With a redshift of 0.04, the $i$-band peak absolute magnitude is derived to be around -17.5. The object is located far away from its host, an early-type galaxy, suggesting it originated from an old stellar population. The spectra collected after the peak are unusually red, show strong UV line blanketing and weak O I $\lambda$7773 absorption lines, and do not evolve significantly over 30 days. An absorption line around 9700-10500 \AA is detected in the near-infrared spectrum and is likely from the unburnt helium in the ejecta. The spectroscopic evolution is consistent with the thermonuclear explosion models for a sub-Chandrasekhar mass white dwarf with a thick helium shell, while the photometric evolution is not well described by existing models.
Comment: accepted for publication in ApJ
Comment: accepted for publication in ApJ