Herschel /PACS view of disks around low-mass stars and brown dwarfs in the TW Hydrae association

Yao Liu, Gregory J. Herczeg, Munan Gong, Katelyn N. Allers, Joanna M. Brown, Adam L. Kraus, Michael C. Liu, Evgenya Shkolnik, Ewine F. Van Dishoeck

Research output: Contribution to journalArticle

Abstract

We conducted Herschel/PACS observations of five very low-mass stars or brown dwarfs located in the TW Hya association with the goal of characterizing the properties of disks in the low stellar mass regime. We detected all five targets at 70 μm and 100 μm and three targets at 160 μm. Our observations, combined with previous photometry from 2MASS, WISE, and SCUBA-2, enabled us to construct spectral energy distributions (SEDs) with extended wavelength coverage. Using sophisticated radiative transfer models, we analyzed the observed SEDs of the five detected objects with a hybrid fitting strategy that combines the model grids and the simulated annealing algorithm and evaluated the constraints on the disk properties via the Bayesian inference method. The modeling suggests that disks around low-mass stars and brown dwarfs are generally flatter than their higher mass counterparts, but the range of disk mass extends to well below the value found in T Tauri stars, and the disk scale heights are comparable in both groups. The inferred disk properties (i.e., disk mass, flaring, and scale height) in the low stellar mass regime are consistent with previous findings from large samples of brown dwarfs and very low-mass stars. We discuss the dependence of disk properties on their host stellar parameters and find a significant correlation between the Herschel far-IR fluxes and the stellar effective temperatures, probably indicating that the scaling between the stellar and disk masses (i.e., Mdisk M) observed mainly in low-mass stars may extend down to the brown dwarf regime.

Original languageEnglish (US)
JournalAstronomy and Astrophysics
Volume573
DOIs
StatePublished - Jan 1 2015
Externally publishedYes

Fingerprint

stars
stellar mass
scale height
spectral energy distribution
Wide-field Infrared Survey Explorer
T Tauri stars
simulated annealing
inference
radiative transfer
photometry
energy
grids
scaling
wavelength
wavelengths
modeling
temperature

Keywords

  • Brown dwarfs
  • Circumstellar matter
  • Protoplanetary disks
  • Stars: low-mass

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Liu, Y., Herczeg, G. J., Gong, M., Allers, K. N., Brown, J. M., Kraus, A. L., ... Van Dishoeck, E. F. (2015). Herschel /PACS view of disks around low-mass stars and brown dwarfs in the TW Hydrae association. Astronomy and Astrophysics, 573. https://doi.org/10.1051/0004-6361/201424721

Herschel /PACS view of disks around low-mass stars and brown dwarfs in the TW Hydrae association. / Liu, Yao; Herczeg, Gregory J.; Gong, Munan; Allers, Katelyn N.; Brown, Joanna M.; Kraus, Adam L.; Liu, Michael C.; Shkolnik, Evgenya; Van Dishoeck, Ewine F.

In: Astronomy and Astrophysics, Vol. 573, 01.01.2015.

Research output: Contribution to journalArticle

Liu, Yao ; Herczeg, Gregory J. ; Gong, Munan ; Allers, Katelyn N. ; Brown, Joanna M. ; Kraus, Adam L. ; Liu, Michael C. ; Shkolnik, Evgenya ; Van Dishoeck, Ewine F. / Herschel /PACS view of disks around low-mass stars and brown dwarfs in the TW Hydrae association. In: Astronomy and Astrophysics. 2015 ; Vol. 573.
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AB - We conducted Herschel/PACS observations of five very low-mass stars or brown dwarfs located in the TW Hya association with the goal of characterizing the properties of disks in the low stellar mass regime. We detected all five targets at 70 μm and 100 μm and three targets at 160 μm. Our observations, combined with previous photometry from 2MASS, WISE, and SCUBA-2, enabled us to construct spectral energy distributions (SEDs) with extended wavelength coverage. Using sophisticated radiative transfer models, we analyzed the observed SEDs of the five detected objects with a hybrid fitting strategy that combines the model grids and the simulated annealing algorithm and evaluated the constraints on the disk properties via the Bayesian inference method. The modeling suggests that disks around low-mass stars and brown dwarfs are generally flatter than their higher mass counterparts, but the range of disk mass extends to well below the value found in T Tauri stars, and the disk scale heights are comparable in both groups. The inferred disk properties (i.e., disk mass, flaring, and scale height) in the low stellar mass regime are consistent with previous findings from large samples of brown dwarfs and very low-mass stars. We discuss the dependence of disk properties on their host stellar parameters and find a significant correlation between the Herschel far-IR fluxes and the stellar effective temperatures, probably indicating that the scaling between the stellar and disk masses (i.e., Mdisk M∗) observed mainly in low-mass stars may extend down to the brown dwarf regime.

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