{
  "id": "2411.01755",
  "version": "v1",
  "published": "2024-11-04T02:38:28.000Z",
  "updated": "2024-11-04T02:38:28.000Z",
  "title": "Revisiting Bondi-Hoyle-Lyttleton accretion in binary systems",
  "authors": [
    "Emilio Tejeda",
    "Jesús A. Toalá"
  ],
  "comment": "15 pages, 2 Tables, 10 Figures; submitted to ApJ (comments are welcome)",
  "categories": [
    "astro-ph.HE",
    "astro-ph.SR"
  ],
  "abstract": "The Bondi-Hoyle-Lyttleton (BHL) accretion model is widely used to describe how a compact object accretes material from a companion's stellar wind in binary systems. However, this classical model becomes inaccurate when the wind velocity ($v_\\mathrm{w}$) is comparable to or less than the orbital velocity ($v_\\mathrm{o}$), predicting nonphysical accretion efficiencies above unity. This limits its applicability to systems with low wind-to-orbital velocity ratios ($w= v_\\mathrm{w}/v_\\mathrm{o} \\leq 1$), such as symbiotic systems. We revisit the BHL model and introduce a geometric correction factor that accounts for the varying orientation of the accretion cylinder relative to the wind direction. This correction ensures physically plausible accretion efficiencies ($\\eta\\leq 1$) for all $w$ in circular orbits. Our modified model naturally predicts the flattening of the accretion efficiency observed in numerical simulations for $w<1$, without the need for ad hoc adjustments. We also peer into the implications of our model for the less-explored case of eccentric orbits, highlighting the key role of the geometric correction factor in shaping the accretion process. We compare our predictions with numerical simulations, finding good agreement for a wide range of parameters. Applications to the symbiotic star R Aqr and the X-ray binary LS 5039 are presented. This improved model offers a more accurate description of wind accretion in binary systems, with implications for stellar evolution, population synthesis, and observational data interpretation.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2024-11-04T02:38:28.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "binary systems",
      "revisiting bondi-hoyle-lyttleton accretion",
      "accretion efficiency",
      "geometric correction factor",
      "ensures physically plausible accretion"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 15,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}