Observational Estimates for the Mass-Loss Rates of Alpha Centauri and Proxima Centauri Using HST Lyman-alpha Spectra

Details Observational Estimates for the Mass-Loss Rates of Alpha Centauri and Proxima Centauri Using HST Lyman-alpha Spectra Observational Estimates for the Mass-Loss Rates of Alpha Centauri and Proxima Centauri Using HST Lyman-alpha Spectra

2000-11-07

arxiv.org/abs/astro-ph/0011153v1

Astronomy and Astrophysics

Astrophysics

11 pages, 3 figures; AASTEX v5.0 plus EPSF extensions in mkfig.sty; accepted by ApJ Letters

Scientific paper

10.1086/318888

We study H I Lyman-alpha absorption observed by the Hubble Space Telescope toward the nearby binary system Alpha Cen (G2 V+K0 V) and its distant companion star Proxima Cen (M5.5 Ve). Absorption from heliospheric H I heated by the solar wind/ISM interaction is observed toward both Alpha Cen and Proxima Cen. Absorption from analogous "astrospheric" material surrounding the stars is detected toward Alpha Cen, but not Proxima Cen. The nondetection of astrospheric absorption toward Proxima Cen suggests that the stellar wind of Proxima Cen must be significantly weaker than that of the Alpha Cen system. We use hydrodynamic models of the astrospheres computed assuming different mass-loss rates to predict astrospheric Lyman-alpha absorption for comparison with the observations. The model that best matches the Alpha Cen data has a mass-loss rate of twice the solar rate, and the models suggest an upper limit of 0.2 solar for Proxima Cen. Finally, we note that the heliospheric absorption observed toward Proxima Cen in 2000 May is identical to the heliospheric absorption observed toward Alpha Cen in 1995 May, implying that the structure of the outer heliosphere does not change significantly during the solar activity cycle.

Affiliated with

Also associated with

No associations

Rating

Observational Estimates for the Mass-Loss Rates of Alpha Centauri and Proxima Centauri Using HST Lyman-alpha Spectra does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Observational Estimates for the Mass-Loss Rates of Alpha Centauri and Proxima Centauri Using HST Lyman-alpha Spectra, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Observational Estimates for the Mass-Loss Rates of Alpha Centauri and Proxima Centauri Using HST Lyman-alpha Spectra will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-125572