Dust Drift Timescales in Protoplanetary Disks at the Cusp of Gravitational Instability

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Autori principali: Williams, Jonathan P., Painter, Caleb, Anderson, Alexa R., Ribas, Alvaro
Natura: Preprint
Pubblicazione: 2024
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author Williams, Jonathan P.
Painter, Caleb
Anderson, Alexa R.
Ribas, Alvaro
author_facet Williams, Jonathan P.
Painter, Caleb
Anderson, Alexa R.
Ribas, Alvaro
contents Millimeter emitting dust grains have sizes that make them susceptible to drift in protoplanetary disks due to a difference between their orbital speed and that of the gas. The characteristic drift timescale depends on the surface density of the gas. By comparing disk radii measurements from ALMA CO and continuum observations at millimeter wavelengths, the gas surface density profile and dust drift time can be self-consistently determined. We find that profiles which match the measured dust mass have very short drift timescales, an order of magnitude or more shorter than the stellar age, whereas profiles for disks that are on the cusp of gravitational instability, defined via the minimum value of the Toomre parameter, Qmin ~ 1-2, have drift timescales comparable to the stellar lifetime. This holds for disks with masses of dust > 5 MEarth across a range of absolute ages from less than 1 Myr to over 10 Myr. The inferred disk masses scale with stellar mass as Mdisk ~ Mstar / 5Qmin. This interpretation of the gas and dust disk sizes simultaneously solves two long standing issues regarding the dust lifetime and exoplanet mass budget and suggests that we consider millimeter wavelength observations as a window into an underlying population of particles with a wide size distribution in secular evolution with a massive planetesimal disk.
format Preprint
id arxiv_https___arxiv_org_abs_2410_06207
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Dust Drift Timescales in Protoplanetary Disks at the Cusp of Gravitational Instability
Williams, Jonathan P.
Painter, Caleb
Anderson, Alexa R.
Ribas, Alvaro
Earth and Planetary Astrophysics
Solar and Stellar Astrophysics
Millimeter emitting dust grains have sizes that make them susceptible to drift in protoplanetary disks due to a difference between their orbital speed and that of the gas. The characteristic drift timescale depends on the surface density of the gas. By comparing disk radii measurements from ALMA CO and continuum observations at millimeter wavelengths, the gas surface density profile and dust drift time can be self-consistently determined. We find that profiles which match the measured dust mass have very short drift timescales, an order of magnitude or more shorter than the stellar age, whereas profiles for disks that are on the cusp of gravitational instability, defined via the minimum value of the Toomre parameter, Qmin ~ 1-2, have drift timescales comparable to the stellar lifetime. This holds for disks with masses of dust > 5 MEarth across a range of absolute ages from less than 1 Myr to over 10 Myr. The inferred disk masses scale with stellar mass as Mdisk ~ Mstar / 5Qmin. This interpretation of the gas and dust disk sizes simultaneously solves two long standing issues regarding the dust lifetime and exoplanet mass budget and suggests that we consider millimeter wavelength observations as a window into an underlying population of particles with a wide size distribution in secular evolution with a massive planetesimal disk.
title Dust Drift Timescales in Protoplanetary Disks at the Cusp of Gravitational Instability
topic Earth and Planetary Astrophysics
Solar and Stellar Astrophysics
url https://arxiv.org/abs/2410.06207