Article Dans Une Revue The Astrophysical Journal Année : 2026

First Resolution of a Main-sequence G star’s Astrosphere Using Chandra

Dimitra Koutroumpa
Jeffrey L Linsky
Mihaly Horanyi
Edward F Guinan
Seth Redfield
Priscilla C Frisch

Résumé

We report the resolution of a halo of X-ray line emission surrounding the zero-age main-sequence G8.5V star HD 61005 by Chandra/ACIS-S. Located only ∼36 pc distant, HD 61005 is young (100 ± 50 Myr) and X-ray bright (∼300 × solar), observed with a nearly edge-on geometry and surrounded by very local interstellar medium (VLISM) material denser than in the Sun's environs. HD 61005 is known to harbor large amounts of circumstellar dust in a dense ecliptic plane full of millimeter-sized particles plus attached, extended "Wing like structures" full of micron-sized particles, which are evidence for strong VLISM-dust disk interaction. These properties aided our ability to resolve the system's ∼220 au wide astrosphere, the first ever observed for a main-sequence G star. The observed X-ray emission morphology is roughly spherical, as expected for an astrospheric structure dominated by the host star. The Chandra spectrum of HD 61005 is a combination of a hard stellar coronal emission (T ∼ 8 MK) at L X ∼ 6 × 10 29 erg s -1 , plus an extended halo contribution at L X ∼ 1 × 10 29 erg s -1 dominated by charge exchange (CX) lines, such as those of O VIII and Ne IX. The Chandra CX X-ray morphology does not track the planar dust morphology but does extend out roughly to ∼110 au where the base of the dust wings begins. We present a toy model of the astrosphere emission produced by stellar wind-VLISM CX interactions, similar to the state of the young Sun when it was only ∼10 8 yr old and transiting through an ∼10 3 times denser part of the interstellar medium (such as a giant molecular cloud).

Fichier principal
Vignette du fichier
Lisse_2026_ApJ_999_125.pdf (38.78 Mo) Télécharger le fichier
Origine Fichiers éditeurs autorisés sur une archive ouverte
Licence

Dates et versions

hal-05539951 , version 1 (06-03-2026)

Licence

Identifiants

Citer

Carey M Lisse, Scott J Wolk, Bradford Snios, Ralph L Mcnutt, Jonathan D Slavin, et al.. First Resolution of a Main-sequence G star’s Astrosphere Using Chandra. The Astrophysical Journal, 2026, 999 (125), pp.21. ⟨10.3847/1538-4357/ae2eda⟩. ⟨hal-05539951⟩
161 Consultations
7 Téléchargements

Altmetric

Partager

  • More