Ballistic Mass Transfer Necessarily Contracts Orbits in Binary Star Systems

Research Notes of the AAS 2026 Open access

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Authors: Jerry (Yuze) Li
DOI: 10.3847/2515-5172/ae4513
Cited by: 0
References: 6

Abstract

Abstract In mass-transferring binary star systems, classical theories show orbital expansion when q = M donor / M accretor < 1. However, these predictions rely on angular momentum conservation. I show that a ballistic prescription, where transferred mass δm carries the donor’s instantaneous velocity, exhibits linear momentum conservation but implies a systematic loss of orbital angular momentum corresponding to an effective external torque. Specifically, the fractional loss of orbital angular momentum yields L f / L i = 1 − f , i.e., fractional angular momentum loss equals fractional mass transferred.

Fields of Study & Subjects

Stellar planetary and galactic studies Astrophysical Phenomena and Observations Galaxies: Formation Evolution Phenomena

Publication details

Journal / source
Research Notes of the AAS
Volume
10
Issue
2
Pages
32–32
Publication date
16 February 2026
Language
EN