Gravitational instability in a planet-forming disk

Fuente: arXiv
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Main Authors: Speedie, Jessica, Dong, Ruobing, Hall, Cassandra, Longarini, Cristiano, Veronesi, Benedetta, Paneque-Carreño, Teresa, Lodato, Giuseppe, Tang, Ya-Wen, Teague, Richard, Hashimoto, Jun
Format: Preprint
Published: 2024
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author Speedie, Jessica
Dong, Ruobing
Hall, Cassandra
Longarini, Cristiano
Veronesi, Benedetta
Paneque-Carreño, Teresa
Lodato, Giuseppe
Tang, Ya-Wen
Teague, Richard
Hashimoto, Jun
author_facet Speedie, Jessica
Dong, Ruobing
Hall, Cassandra
Longarini, Cristiano
Veronesi, Benedetta
Paneque-Carreño, Teresa
Lodato, Giuseppe
Tang, Ya-Wen
Teague, Richard
Hashimoto, Jun
contents The canonical theory for planet formation in circumstellar disks proposes that planets are grown from initially much smaller seeds. The long-considered alternative theory proposes that giant protoplanets can be formed directly from collapsing fragments of vast spiral arms induced by gravitational instability -- if the disk is gravitationally unstable. For this to be possible, the disk must be massive compared to the central star: a disk-to-star mass ratio of 1/10 is widely held as the rough threshold for triggering gravitational instability, inciting significant non-Keplerian dynamics and generating prominent spiral arms. While estimating disk masses has historically been challenging, the motion of the gas can reveal the presence of gravitational instability through its effect on the disk velocity structure. Here we present kinematic evidence of gravitational instability in the disk around AB Aurigae, using deep observations of 13CO and C18O line emission with the Atacama Large Millimeter/submillimeter Array (ALMA). The observed kinematic signals strongly resemble predictions from simulations and analytic modelling. From quantitative comparisons, we infer a disk mass of up to 1/3 the stellar mass enclosed within 1" to 5" on the sky.
format Preprint
id arxiv_https___arxiv_org_abs_2409_02196
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Gravitational instability in a planet-forming disk
Speedie, Jessica
Dong, Ruobing
Hall, Cassandra
Longarini, Cristiano
Veronesi, Benedetta
Paneque-Carreño, Teresa
Lodato, Giuseppe
Tang, Ya-Wen
Teague, Richard
Hashimoto, Jun
Earth and Planetary Astrophysics
The canonical theory for planet formation in circumstellar disks proposes that planets are grown from initially much smaller seeds. The long-considered alternative theory proposes that giant protoplanets can be formed directly from collapsing fragments of vast spiral arms induced by gravitational instability -- if the disk is gravitationally unstable. For this to be possible, the disk must be massive compared to the central star: a disk-to-star mass ratio of 1/10 is widely held as the rough threshold for triggering gravitational instability, inciting significant non-Keplerian dynamics and generating prominent spiral arms. While estimating disk masses has historically been challenging, the motion of the gas can reveal the presence of gravitational instability through its effect on the disk velocity structure. Here we present kinematic evidence of gravitational instability in the disk around AB Aurigae, using deep observations of 13CO and C18O line emission with the Atacama Large Millimeter/submillimeter Array (ALMA). The observed kinematic signals strongly resemble predictions from simulations and analytic modelling. From quantitative comparisons, we infer a disk mass of up to 1/3 the stellar mass enclosed within 1" to 5" on the sky.
title Gravitational instability in a planet-forming disk
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2409.02196