{
  "id": "2105.02227",
  "version": "v1",
  "published": "2021-05-05T18:00:00.000Z",
  "updated": "2021-05-05T18:00:00.000Z",
  "title": "Common envelope evolution of eccentric binaries",
  "authors": [
    "Hila Glanz",
    "Hagai B. Perets"
  ],
  "comment": "Comments are welcomed",
  "categories": [
    "astro-ph.SR"
  ],
  "abstract": "Common envelope evolution (CEE) is believed to be an important stage in the evolution of binary/multiple stellar systems. Following this stage, the CE is thought to be ejected, leaving behind a compact binary (or a merger product). Although extensively studied, the CEE process is still little understood, and although most binaries have non-negligible eccentricity, the effect of initial eccentricity on the CEE has been little explored. Moreover, most studies assume a complete circularization of the orbit by the CE onset, while observationally such eccentricities are detected in many post-CE binaries. Here we use smoothed particle hydro-dynamical simulations (SPH) to study the evolution of initially eccentric ($0\\le e\\le0.95$) CE-systems. We find that initially eccentric binaries only partially circularize. In addition, higher initial eccentricity leads to a higher post-CE eccentricity, with eccentricities of post-CE binaries as high as 0.2 in the most eccentric cases, and even higher if the initial peri-center of the orbit is located inside the star (e.g. following a kick into an eccentric orbit, rather than a smooth transition). CEE of more eccentric binaries leads to enhanced dynamical mass-loss of the CE compared with more circular binaries, and depends on the initial closest approach of the binary. We show that our results and the observed eccentricities of post-CE binaries suggest that the typical assumptions of circular orbits following CEE should potentially be revised. We expect post-CE eccentricities to affect the delay time distributions of various transients such as supernovae, gamma-ray bursts and gravitational-wave sources by up to tens of percents.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2021-05-05T18:00:00.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "common envelope evolution",
      "eccentric binaries",
      "post-ce binaries",
      "initially eccentric",
      "higher initial eccentricity"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}