Gas infall via accretion disk feeding Cepheus A HW2

Fuente: arXiv
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Auteurs principaux: Sanna, A., Oliva, A., Moscadelli, L., Carrasco-González, C., Giannetti, A., Sabatini, G., Beltrán, M., Brogan, C., Hunter, T., Torrelles, J. M., Rodríguez-Kamenetzky, A., Garatti, A. Caratti o, Kuiper, R.
Format: Preprint
Publié: 2025
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author Sanna, A.
Oliva, A.
Moscadelli, L.
Carrasco-González, C.
Giannetti, A.
Sabatini, G.
Beltrán, M.
Brogan, C.
Hunter, T.
Torrelles, J. M.
Rodríguez-Kamenetzky, A.
Garatti, A. Caratti o
Kuiper, R.
author_facet Sanna, A.
Oliva, A.
Moscadelli, L.
Carrasco-González, C.
Giannetti, A.
Sabatini, G.
Beltrán, M.
Brogan, C.
Hunter, T.
Torrelles, J. M.
Rodríguez-Kamenetzky, A.
Garatti, A. Caratti o
Kuiper, R.
contents The star-forming region Cepheus A hosts a very young star, called HW2, that is the second closest to us growing a dozen times more massive than our Sun. The circumstellar environment surrounding HW2 has long been the subject of much debate about the presence or not of an accretion disk, whose existence is at the basis of our current paradigm of star formation. Here, we answer this long standing question by resolving the gaseous disk component, and its kinematics, through sensitive observations at cm wavelengths of hot ammonia (NH$_3$) with the Jansky Very Large Array. We map the accretion disk surrounding HW2 at radii between 200 and 700 au, showing how fast circumstellar gas collapses and slowly orbits to pile up near the young star at very high rates of $2\times10^{-3}$ M$_{\odot}$ yr$^{-1}$. These results, corroborated by state-of-the-art simulations, show that an accretion disk is still efficient in focusing huge mass infall rates near the young star, even when this star has already reached a large mass of 16 M$_{\odot}$.
format Preprint
id arxiv_https___arxiv_org_abs_2502_15070
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Gas infall via accretion disk feeding Cepheus A HW2
Sanna, A.
Oliva, A.
Moscadelli, L.
Carrasco-González, C.
Giannetti, A.
Sabatini, G.
Beltrán, M.
Brogan, C.
Hunter, T.
Torrelles, J. M.
Rodríguez-Kamenetzky, A.
Garatti, A. Caratti o
Kuiper, R.
Solar and Stellar Astrophysics
Astrophysics of Galaxies
The star-forming region Cepheus A hosts a very young star, called HW2, that is the second closest to us growing a dozen times more massive than our Sun. The circumstellar environment surrounding HW2 has long been the subject of much debate about the presence or not of an accretion disk, whose existence is at the basis of our current paradigm of star formation. Here, we answer this long standing question by resolving the gaseous disk component, and its kinematics, through sensitive observations at cm wavelengths of hot ammonia (NH$_3$) with the Jansky Very Large Array. We map the accretion disk surrounding HW2 at radii between 200 and 700 au, showing how fast circumstellar gas collapses and slowly orbits to pile up near the young star at very high rates of $2\times10^{-3}$ M$_{\odot}$ yr$^{-1}$. These results, corroborated by state-of-the-art simulations, show that an accretion disk is still efficient in focusing huge mass infall rates near the young star, even when this star has already reached a large mass of 16 M$_{\odot}$.
title Gas infall via accretion disk feeding Cepheus A HW2
topic Solar and Stellar Astrophysics
Astrophysics of Galaxies
url https://arxiv.org/abs/2502.15070