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”
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We are always interested to work with students on all levels (Bachelor, Masters, PhD). Possible topics include core-collapse supernovae, stellar mergers, eclipsing binaries, variable stars, stellar dynamics, (magneto)hydrodynamics, radiation transport, “big data”, etc. Many of these issues are directly related to the important unsolved problems of contemporary astrophysics. The group has access to the All-Sky Automated Survey for Supernovae (ASAS-SN). Team members work within international collaborations. Please contact us if you’d like to know more.