Bibliographic Details
| Title: |
ZTF 18aaqeasu (SN 2018byg): A Massive Helium-shell Double Detonation on a Sub-Chandrasekhar Mass White Dwarf |
| Authors: |
De, Kishalay, Kasliwal, Mansi M., Polin, Abigail, Nugent, Peter E., Bildsten, Lars, Adams, Scott M., Bellm, Eric C., Blagorodnova, Nadia, Burdge, Kevin B., Cannella, Christopher, Cenko, S. Bradley, Dekany, Richard G., Feeney, Michael, Hale, David, Fremling, Christoffer, Graham, Matthew J., Ho, Anna Y. Q., Jencson, Jacob E., Kulkarni, S. R., Laher, Russ R., Masci, Frank J., Miller, Adam A., Patterson, Maria T., Rebbapragada, Umaa, Riddle, Reed L., Shupe, David L., Smith, Roger M. |
| Publication Year: |
2019 |
| Collection: |
Astrophysics |
| Subject Terms: |
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Solar and Stellar Astrophysics |
| More Details: |
The detonation of a helium shell on a white dwarf has been proposed as a possible explosion triggering mechanism for Type Ia supernovae. Here, we report ZTF 18aaqeasu (SN 2018byg/ATLAS 18pqq), a peculiar Type I supernova, consistent with being a helium-shell double-detonation. With a rise time of $\approx 18$ days from explosion, the transient reached a peak absolute magnitude of $M_R \approx -18.2$ mag, exhibiting a light curve akin to sub-luminous SN 1991bg-like Type Ia supernovae, albeit with an unusually steep increase in brightness within a week from explosion. Spectra taken near peak light exhibit prominent Si absorption features together with an unusually red color ($g-r \approx 2$ mag) arising from nearly complete line blanketing of flux blue-wards of 5000 \AA. This behavior is unlike any previously observed thermonuclear transient. Nebular phase spectra taken at and after $\approx 30$ days from peak light reveal evidence of a thermonuclear detonation event dominated by Fe-group nucleosynthesis. We show that the peculiar properties of ZTF 18aaqeasu are consistent with the detonation of a massive ($\approx 0.15$ M$_\odot$) helium shell on a sub-Chandrasekhar mass ($\approx 0.75$ M$_\odot$) white dwarf after including mixing of $\approx 0.2$ M$_\odot$ of material in the outer ejecta. These observations provide evidence of a likely rare class of thermonuclear supernovae arising from detonations of massive helium shells.
Comment: 10 pages, 6 figures. Submitted to ApJL |
| Document Type: |
Working Paper |
| DOI: |
10.3847/2041-8213/ab0aec |
| Access URL: |
http://arxiv.org/abs/1901.00874 |
| Accession Number: |
edsarx.1901.00874 |
| Database: |
arXiv |
