Presentation #404.03 in the session Stellar Populations & Evolution — iPoster Session.
The Octo-Tiger simulation models the merger of the two main-sequence stars in the V1309 Sco contact binary and between two hypothetical degenerate stars, calculating the evolution of the system over time via the interaction of millions of cells. Over the course of the simulation, cells are identified as belonging to either the donor or accretor. Thus, the characteristics of each star can be calculated via the characteristics of their constituent cells. These summary statistics can be used to verify the integrity of the Octo-Tiger simulation via basic analytical methods as well as gain useful insights into the process of stellar merger. Conservation laws as well as [the binary mass transfer equation] were observed to a high degree of accuracy until [shortly before collision], lending credence to Octo-Tiger’s findings. Comparing the orbital angular velocity of the binary to the rotation rate of each star further indicates that the transfer of angular momentum of the system inwards was primarily caused by Darwin instability in V1309 Sco, whereas in a hypothetical merger event between two degenerate stars, accretion was the primary driver. These findings all reinforce theories of stellar merger advanced by the Octo-Tiger research group.
Bennett Skinner acknowledges support from the REU Site in Physics and Astronomy (NSF Grant No. 1852356) at Louisiana State University.