Planets In and Around Binary Star Systems

Under the supervision of Dr. Richard Parker at the University of Sheffield, UK, I investigated the gravitational stability of planetary orbits in binary star systems, where two stars orbit around each other.

Most stars form in binary (or higher order multiple) systems (Duquennoy & Mayor, 1991; Connelley et al., 2008; Raghavan et al., 2010; Duchêne et al., 2013; Pineda et al., 2015), within a crowded star-forming region (Lada & Lada, 2003; Gutermuth et al., 2009; Bressert et al., 2010). This dense stellar environment leads to gravitational interactions between stars that can affect their orbits. Could such orbital changes also affect the stability of planets that may reside in these binary star systems?

Using N-body simulations of star-forming regions we found that, while some planets can become unstable, the overwhelming majority remain largely unaffected. In other words, if a planet forms in a binary system it will most likely remain stable. Therefore, with the knowledge that it is more difficult to form planets in binary systems than around single stars (Holman & Wiegert, 1999), we can infer that the critical factor in determining the number of stable planetary systems in the Galaxy is the stellar binary fraction—more stars born as singles means more stable planets.

This work was published in the Monthly Notices of the Royal Astronomical Society (MNRAS). A video abstract for this publication was created by Helena Gibbon, a Science Communication MSc student at the University of Sheffield, as can be seen below:

References:
Bressert E. et al., 2010, MNRAS, 409, L54
Connelley M. S., Reipurth B., Tokunaga A. T., 2008, AJ, 135, 2526 Cournoyer-Cloutier
Duchêne G., Bouvier J., Moraux E., Bouy H., Konopacky Q., Ghez A. M., 2013, A&A, 555, A137
Duquennoy A., Mayor M., 1991, A&A, 248, 485
Gutermuth R. A., Megeath S. T., Myers P. C., Allen L. E., Pipher J. L., Fazio G. G., 2009, ApJS, 184, 18
Holman M. J., Wiegert P. A., 1999, AJ, 117, 621
Lada C. J., Lada E. A., 2003, ARA&A, 41, 57
Pineda J. E. et al., 2015, Nature, 518, 213
Raghavan D. et al., 2010, ApJSS, 190, 1