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Journal Articles The Astrophysical Journal Year : 2012

Mass Loss in Pre-main-sequence Stars via Coronal Mass Ejections and Implications for Angular Momentum Loss

Alicia N. Aarnio
  • Function : Author
Keivan G. Stassun
  • Function : Author

Abstract

We develop an empirical model to estimate mass-loss rates via coronal mass ejections (CMEs) for solar-type pre-main-sequence (PMS) stars. Our method estimates the CME mass-loss rate from the observed energies of PMS X-ray flares, using our empirically determined relationship between solar X-ray flare energy and CME mass: log (M CME[g]) = 0.63 × log (E flare[erg]) - 2.57. Using masses determined for the largest flaring magnetic structures observed on PMS stars, we suggest that this solar-calibrated relationship may hold over 10 orders of magnitude in flare energy and 7 orders of magnitude in CME mass. The total CME mass-loss rate we calculate for typical solar-type PMS stars is in the range 10-12-10-9 M yr-1. We then use these CME mass-loss rate estimates to infer the attendant angular momentum loss leading up to the main sequence. Assuming that the CME outflow rate for a typical ~1 M T Tauri star is <10-10 M yr-1, the resulting spin-down torque is too small during the first ~1 Myr to counteract the stellar spin-up due to contraction and accretion. However, if the CME mass-loss rate is >~ 10-10 M yr-1, as permitted by our calculations, then the CME spin-down torque may influence the stellar spin evolution after an age of a few Myr.

Dates and versions

insu-03621687 , version 1 (28-03-2022)

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Alicia N. Aarnio, Sean P. Matt, Keivan G. Stassun. Mass Loss in Pre-main-sequence Stars via Coronal Mass Ejections and Implications for Angular Momentum Loss. The Astrophysical Journal, 2012, 760, ⟨10.1088/0004-637X/760/1/9⟩. ⟨insu-03621687⟩
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