We present the discovery, photometric and spectroscopic follow-up observations of SN 2010X (PTF 10bhp). This supernova decays exponentially with tau_d=5 days, and rivals the current recordholder in speed, SN 2002bj. SN 2010X peaks at M_r=-17mag and has mean velocities of 10,000 km/s. Our light curve modeling suggests a radioactivity powered event and an ejecta mass of 0.16 Msun. If powered by Nickel, we show that the Nickel mass must be very small (0.02 Msun) and that the supernova quickly becomes optically thin to gamma-rays. Our spectral modeling suggests that SN 2010X and SN 2002bj have similar chemical compositions and that one of Aluminum or Helium is present. If Aluminum is present, we speculate that this may be an accretion induced collapse of an O-Ne-Mg white dwarf. If Helium is present, all observables of SN 2010X are consistent with being a thermonuclear Helium shell detonation on a white dwarf, a ".Ia" explosion. With the 1-day dynamic-cadence experiment on the Palomar Transient Factory, we expect to annually discover a few such events.
@article{arxiv.1009.0960,
title = {Rapidly Decaying Supernova 2010X: A Candidate ".Ia" Explosion},
author = {Mansi M. Kasliwal and S. R. Kulkarni and Avishay Gal-Yam and Ofer Yaron and Robert M. Quimby and Eran O. Ofek and Peter Nugent and Dovi Poznanski and Janet Jacobsen and Assaf Sternberg and Iair Arcavi and D. Andrew Howell and Mark Sullivan and Douglas J Rich and Paul F Burke and Joseph Brimacombe MB ChB FRCA MD and Dan Milisavljevic and Robert Fesen and Lars Bildsten and Ken Shen and S. Bradley Cenko and Joshua S. Bloom and Eric Hsiao and Nicholas M. Law and Neil Gehrels and Stefan Immler and Richard Dekany and Gustavo Rahmer and David Hale and Roger Smith and Jeff Zolkower and Viswa Velur and Richard Walters and John Henning and Kahnh Bui and Dan McKenna},
journal= {arXiv preprint arXiv:1009.0960},
year = {2015}
}
Comments
6 pages, 5 figures; Minor Changes; Note correction in Fig 4 caption; published by ApJL