Ondřej Pejcha

Spent the last couple days at University of Delaware giving a seminar about supernovae and stellar mergers, and talking to Stan Owocki and others.

Spent the last week at Ohio State University discussing stellar evolution, transients, binary stars, asteroids, ASAS-SN, and meeting up with Michał Pawlak, who is visiting OSU for a longer period.

At Columbia today, discussing shocks and dust in stellar mergers, novae and supernovae with Brian Metzger and Elad Steinberg.

Matthias Raives et al. studied transition from accretion to explosion in highly idealized setting of the neutrino mechanism of core-collapse supernovae and in relation to the critical neutrino luminosity of Burrows & Goshy (1993) and extending the previous work of Pejcha & Thompson (2012). Interestingly, in order to properly resolve the vicinity of the critical transition, high simulation resolution is needed.

The full paper is available at astro-ph.

Paper with Brian Metzger, Jacob Tyles and Kengo Tomida on the best-studied example of stellar mergers V1309 Sco. We explain the pre-maximum behavior as due to runaway increase of mass loss from the outer Lagrange L2 of a contact binary. The resulting spiral stream initially obscures the binary and modifies the light curve. Then, mass-loss rate is so high that the binary variability disappears and we see only shocks from collision of the spiral arms. We can track mass-loss rate by looking at the luminosity (with some caveats).  When the merger becomes dynamical, the faster more-spherical explosion collides with the previous equatorially-focused mass loss. The resulting shock interaction can power bright second peaks in many similar transients. Continue reading “Pre-explosion spiral mass loss of a binary star merger”