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Title: Hints for Small Disks around Very Low Mass Stars and Brown Dwarfs

Abstract

The properties of disks around brown dwarfs and very low mass stars (hereafter VLMOs) provide important boundary conditions on the process of planet formation and inform us about the numbers and masses of planets than can form in this regime. We use the Herschel Space Observatory PACS spectrometer to measure the continuum and [O i] 63 μ m line emission toward 11 VLMOs with known disks in the Taurus and Chamaeleon I star-forming regions. We fit radiative transfer models to the spectral energy distributions of these sources. Additionally, we carry out a grid of radiative transfer models run in a regime that connects the luminosity of our sources with brighter T Tauri stars. We find that VLMO disks with sizes 1.3–78 au, smaller than typical T Tauri disks, fit well the spectral energy distributions assuming that disk geometry and dust properties are stellar mass independent. Reducing the disk size increases the disk temperature, and we show that VLMOs do not follow previously derived disk temperature–stellar luminosity relationships if the disk outer radius scales with stellar mass. Only 2 out of 11 sources are detected in [O i] despite a better sensitivity than was achieved for T Tauri stars, suggesting thatmore » VLMO disks are underluminous. Using thermochemical models, we show that smaller disks can lead to the unexpected [O i] 63 μ m nondetections in our sample. The disk outer radius is an important factor in determining the gas and dust observables. Hence, spatially resolved observations with ALMA—to establish if and how disk radii scale with stellar mass—should be pursued further.« less

Authors:
; ;  [1]; ;  [2];  [3];  [4];  [5];  [6]
  1. Lunar and Planetary Laboratory, The University of Arizona, Tucson, AZ 85721 (United States)
  2. Kapteyn Astronomical Institute, University of Groningen, Postbus 800, 9700 AV Groningen (Netherlands)
  3. Max Planck Institute for Astronomy, Konigstuhl 17, D-69117 Heidelberg (Germany)
  4. Univ. Grenoble Alpes, CNRS, IPAG, F-38000 Grenoble (France)
  5. Department of Engineering, Atacama Large Millimeter/submillimeter Array (ALMA) Santiago Central Offices, Alonso de Córdova 3107, Vitacura, Casilla 763 0355, Santiago (Chile)
  6. Department of Astronomy, The University of Texas at Austin, Austin, TX 78712 (United States)
Publication Date:
OSTI Identifier:
22663553
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 841; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BOUNDARY CONDITIONS; DUSTS; DWARF STARS; EMISSION; ENERGY SPECTRA; LUMINOSITY; MASS; PERTURBED ANGULAR CORRELATION; PLANETS; PROTOPLANETS; RADIANT HEAT TRANSFER; SENSITIVITY; SPACE; SPECTROMETERS; T TAURI STARS

Citation Formats

Hendler, Nathanial P., Mulders, Gijs D., Pascucci, Ilaria, Greenwood, Aaron, Kamp, Inga, Henning, Thomas, Ménard, François, Dent, William R. F., and II, Neal J. Evans, E-mail: equant@lpl.arizona.edu. Hints for Small Disks around Very Low Mass Stars and Brown Dwarfs. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA71B8.
Hendler, Nathanial P., Mulders, Gijs D., Pascucci, Ilaria, Greenwood, Aaron, Kamp, Inga, Henning, Thomas, Ménard, François, Dent, William R. F., & II, Neal J. Evans, E-mail: equant@lpl.arizona.edu. Hints for Small Disks around Very Low Mass Stars and Brown Dwarfs. United States. doi:10.3847/1538-4357/AA71B8.
Hendler, Nathanial P., Mulders, Gijs D., Pascucci, Ilaria, Greenwood, Aaron, Kamp, Inga, Henning, Thomas, Ménard, François, Dent, William R. F., and II, Neal J. Evans, E-mail: equant@lpl.arizona.edu. Thu . "Hints for Small Disks around Very Low Mass Stars and Brown Dwarfs". United States. doi:10.3847/1538-4357/AA71B8.
@article{osti_22663553,
title = {Hints for Small Disks around Very Low Mass Stars and Brown Dwarfs},
author = {Hendler, Nathanial P. and Mulders, Gijs D. and Pascucci, Ilaria and Greenwood, Aaron and Kamp, Inga and Henning, Thomas and Ménard, François and Dent, William R. F. and II, Neal J. Evans, E-mail: equant@lpl.arizona.edu},
abstractNote = {The properties of disks around brown dwarfs and very low mass stars (hereafter VLMOs) provide important boundary conditions on the process of planet formation and inform us about the numbers and masses of planets than can form in this regime. We use the Herschel Space Observatory PACS spectrometer to measure the continuum and [O i] 63 μ m line emission toward 11 VLMOs with known disks in the Taurus and Chamaeleon I star-forming regions. We fit radiative transfer models to the spectral energy distributions of these sources. Additionally, we carry out a grid of radiative transfer models run in a regime that connects the luminosity of our sources with brighter T Tauri stars. We find that VLMO disks with sizes 1.3–78 au, smaller than typical T Tauri disks, fit well the spectral energy distributions assuming that disk geometry and dust properties are stellar mass independent. Reducing the disk size increases the disk temperature, and we show that VLMOs do not follow previously derived disk temperature–stellar luminosity relationships if the disk outer radius scales with stellar mass. Only 2 out of 11 sources are detected in [O i] despite a better sensitivity than was achieved for T Tauri stars, suggesting that VLMO disks are underluminous. Using thermochemical models, we show that smaller disks can lead to the unexpected [O i] 63 μ m nondetections in our sample. The disk outer radius is an important factor in determining the gas and dust observables. Hence, spatially resolved observations with ALMA—to establish if and how disk radii scale with stellar mass—should be pursued further.},
doi = {10.3847/1538-4357/AA71B8},
journal = {Astrophysical Journal},
number = 2,
volume = 841,
place = {United States},
year = {Thu Jun 01 00:00:00 EDT 2017},
month = {Thu Jun 01 00:00:00 EDT 2017}
}