Λεπτομέρειες βιβλιογραφικής εγγραφής
| Τίτλος: |
Direct Optical Evidence of Late-stage Infall in AB Aurigae: A Stagnant [O I ] Reservoir and a Crushed Magnetosphere. |
| Συγγραφείς: |
Sahu, Dipen1 (AUTHOR) dsahu@prl.res.in, Sharma, Rishikesh1 (AUTHOR), Das, Shubhendra Nath1,2 (AUTHOR), Chakraborty, Abhijit1 (AUTHOR), Campbell-White, Justyn3 (AUTHOR) |
| Πηγή: |
Astrophysical Journal. 2026, Vol. 1006 Issue 2, p1-13. 13p. |
| Θεματικοί όροι: |
*Accretion (Astrophysics), *Magnetosphere, *Circumstellar matter, *Protoplanetary disks, *Optical spectroscopy, *Stars |
| Περίληψη: |
Massive planet-carved cavities in transition disks should theoretically throttle inward gas transport, challenging our understanding of how central stars maintain vigorous accretion. To investigate how macroscale late-stage infall traverses these gaps, we present multiepoch, extreme-resolution (R ≈ 107,000) PARAS-2 optical spectroscopy of the benchmark Herbig Ae system AB Aurigae. By resolving the kinematics of H α, He I λ 5876, [O I ] λλ 6300, 6363, and Na I D, we map the innermost accretion environment. We find that the [O I ] emission is centered near the stellar rest velocity with symmetric broadening of ∼35 km s−1. Restricted to T ≲ 3800 K, this profile traces a stagnant, gravitationally bound Keplerian gas reservoir at ∼1 au. Therefore, it provides strong optical evidence that late-stage infall accumulates in an inner gas reservoir and subsequently feeds the innermost dust cavity. From this reservoir, gas is transported inward and crashes onto the star, driving a highly active accretion rate of M ̇ acc ≈ 4 × 1 0 − 7 M ⊙ yr − 1 . The associated ram pressure crushes the stellar magnetosphere to R mag ≈ 1.2 R ⋆, which explains the restricted He I freefall velocities and the highly variable inner wind. We also isolate a stable, slow H α wind component, likely tracing an extended photoevaporative disk wind. [ABSTRACT FROM AUTHOR] |
| Βάση Δεδομένων: |
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