Mapping the merging zone of late infall in the AB Aur planet-forming system

Fuente: arXiv
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Main Authors: Speedie, Jessica, Dong, Ruobing, Teague, Richard, Segura-Cox, Dominique, Pineda, Jaime E., Calcino, Josh, Longarini, Cristiano, Hall, Cassandra, Tang, Ya-Wen, Hashimoto, Jun, Paneque-Carreño, Teresa, Lodato, Giuseppe, Veronesi, Bennedetta
Format: Preprint
Published: 2025
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author Speedie, Jessica
Dong, Ruobing
Teague, Richard
Segura-Cox, Dominique
Pineda, Jaime E.
Calcino, Josh
Longarini, Cristiano
Hall, Cassandra
Tang, Ya-Wen
Hashimoto, Jun
Paneque-Carreño, Teresa
Lodato, Giuseppe
Veronesi, Bennedetta
author_facet Speedie, Jessica
Dong, Ruobing
Teague, Richard
Segura-Cox, Dominique
Pineda, Jaime E.
Calcino, Josh
Longarini, Cristiano
Hall, Cassandra
Tang, Ya-Wen
Hashimoto, Jun
Paneque-Carreño, Teresa
Lodato, Giuseppe
Veronesi, Bennedetta
contents Late infall events challenge the traditional view that planet formation occurs without external influence. Here we present deep ALMA $^{12}$CO $J=2-1$ and SO $J_{N}=5_6-4_5$ observations toward AB Aurigae, a Class II disk system with strong signs of gravitational instability and ongoing planet formation. By applying Keplerian and anti-Keplerian masks, we separate disk-like and non-disk-like motions of $^{12}$CO, considering the two outputs as the 'disk' and 'exo-disk' (out of disk) emission components, respectively. The disk component of $^{12}$CO extends to $\sim 1600$ au in radius and exhibits a stunningly rich architecture of global spiral structure. The exo-disk emission consists predominantly of three spiral structures -- S1, S2 and S3 -- whose projections are co-spatial with the disk. We successfully reproduce their trajectories with a ballistic accretion flow model, finding that S1 and S2 (both redshifted) are infalling toward the disk from in front, and S3 (blueshifted) is infalling from behind. Where the terminal ends of S1 and S2 become indistinguishable from the disk, we observe a brightness peak in SO emission $2.5\times$ the azimuthal average of a background SO ring. This merging zone lies within a relatively confined region $15-100$ degrees east of north, and between $\sim150-300$ au from the star, at scales relevant to where planet candidates have been previously identified. The AB Aur system provides a unified picture of late infall inducing replenishment of the disk, triggering gravitational instability, and modifying the conditions of forming planets.
format Preprint
id arxiv_https___arxiv_org_abs_2503_01957
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Mapping the merging zone of late infall in the AB Aur planet-forming system
Speedie, Jessica
Dong, Ruobing
Teague, Richard
Segura-Cox, Dominique
Pineda, Jaime E.
Calcino, Josh
Longarini, Cristiano
Hall, Cassandra
Tang, Ya-Wen
Hashimoto, Jun
Paneque-Carreño, Teresa
Lodato, Giuseppe
Veronesi, Bennedetta
Earth and Planetary Astrophysics
Late infall events challenge the traditional view that planet formation occurs without external influence. Here we present deep ALMA $^{12}$CO $J=2-1$ and SO $J_{N}=5_6-4_5$ observations toward AB Aurigae, a Class II disk system with strong signs of gravitational instability and ongoing planet formation. By applying Keplerian and anti-Keplerian masks, we separate disk-like and non-disk-like motions of $^{12}$CO, considering the two outputs as the 'disk' and 'exo-disk' (out of disk) emission components, respectively. The disk component of $^{12}$CO extends to $\sim 1600$ au in radius and exhibits a stunningly rich architecture of global spiral structure. The exo-disk emission consists predominantly of three spiral structures -- S1, S2 and S3 -- whose projections are co-spatial with the disk. We successfully reproduce their trajectories with a ballistic accretion flow model, finding that S1 and S2 (both redshifted) are infalling toward the disk from in front, and S3 (blueshifted) is infalling from behind. Where the terminal ends of S1 and S2 become indistinguishable from the disk, we observe a brightness peak in SO emission $2.5\times$ the azimuthal average of a background SO ring. This merging zone lies within a relatively confined region $15-100$ degrees east of north, and between $\sim150-300$ au from the star, at scales relevant to where planet candidates have been previously identified. The AB Aur system provides a unified picture of late infall inducing replenishment of the disk, triggering gravitational instability, and modifying the conditions of forming planets.
title Mapping the merging zone of late infall in the AB Aur planet-forming system
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2503.01957