Herschel survey of brown dwarf disks in ρ Ophiuchi

C. Alves De Oliveira, P. Ábrahám, G. Marton, C. Pinte, C. Kiss, M. Kun, A. Kóspál, P. André, V. Könyves

Research output: Article

16 Citations (Scopus)

Abstract

Context. Young brown dwarfs are known to possess circumstellar disks, a characteristic that is fundamental to the understanding of their formation process, and raises the possibility that these objects harbour planets. Aims. We want to characterise the far-IR emission of disks around the young brown dwarf population of the ρ Ophiuchi cluster in LDN 1688. Methods. Recent observations of the ρ Ophiuchi cluster with the Herschel Space Observatory allow us to probe the spectral energy distribution (SED) of the brown dwarf population in the far-IR, where the disk emission peaks. We performed aperture photometry at 70, 100, and 160 μm, and constructed SEDs for all previously known brown dwarfs detected. These were complemented with ancillary photometry at shorter wavelengths. We compared the observed SEDs to a grid of synthetic disks produced with the radiative transfer code MCFOST, and used the relative figure of merit estimated from the Bayesian inference of each disk parameter to analyse the structural properties. Results. We detected 12 Class II brown dwarfs with Herschel, which corresponds to one-third of all currently known brown dwarf members of ρ Ophiuchi. We did not detect any of the known Class III brown dwarfs. Comparison to models reveals that the disks are best described by an inner radius between 0.01 and 0.07 AU, and a flared disk geometry with a flaring index between 1.05 and 1.2. Furthermore, we can exclude values of the disk scale-height lower than 10 AU (measured at a fiducial radius of 100 AU). We combined the Herschel data with recent ALMA observations of the brown dwarf GY92 204 (ISO-Oph 102), and by comparing its SED to the same grid of disk models, we derived an inner disk radius of 0.035 AU, a scale height of 15 AU with a flaring index of β ~ 1.15, an exponent for dust settling of-1.5, and a disk mass of 0.001 M⊙. This corresponds to a disk-to-central object mass ratio of ~1%. Conclusions. The structural parameters constrained by the extended SED coverage (inner radius and flaring index) show a narrow distribution for the young brown dwarfs detected in ρ Ophiuchi, suggesting that these objects share the same disk evolution and, perhaps, formation.

Original languageEnglish
Article numberA126
JournalAstronomy and Astrophysics
Volume559
DOIs
Publication statusPublished - 2013

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energy
spectral energy distribution
radiative transfer
harbor
planet
observatory
probe
radii
scale height
dust
wavelength
geometry
distribution
photometry
grids
flaring
young
index
harbors
settling

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Herschel survey of brown dwarf disks in ρ Ophiuchi. / Alves De Oliveira, C.; Ábrahám, P.; Marton, G.; Pinte, C.; Kiss, C.; Kun, M.; Kóspál, A.; André, P.; Könyves, V.

In: Astronomy and Astrophysics, Vol. 559, A126, 2013.

Research output: Article

Alves De Oliveira, C, Ábrahám, P, Marton, G, Pinte, C, Kiss, C, Kun, M, Kóspál, A, André, P & Könyves, V 2013, 'Herschel survey of brown dwarf disks in ρ Ophiuchi', Astronomy and Astrophysics, vol. 559, A126. https://doi.org/10.1051/0004-6361/201322402
Alves De Oliveira, C. ; Ábrahám, P. ; Marton, G. ; Pinte, C. ; Kiss, C. ; Kun, M. ; Kóspál, A. ; André, P. ; Könyves, V. / Herschel survey of brown dwarf disks in ρ Ophiuchi. In: Astronomy and Astrophysics. 2013 ; Vol. 559.
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abstract = "Context. Young brown dwarfs are known to possess circumstellar disks, a characteristic that is fundamental to the understanding of their formation process, and raises the possibility that these objects harbour planets. Aims. We want to characterise the far-IR emission of disks around the young brown dwarf population of the ρ Ophiuchi cluster in LDN 1688. Methods. Recent observations of the ρ Ophiuchi cluster with the Herschel Space Observatory allow us to probe the spectral energy distribution (SED) of the brown dwarf population in the far-IR, where the disk emission peaks. We performed aperture photometry at 70, 100, and 160 μm, and constructed SEDs for all previously known brown dwarfs detected. These were complemented with ancillary photometry at shorter wavelengths. We compared the observed SEDs to a grid of synthetic disks produced with the radiative transfer code MCFOST, and used the relative figure of merit estimated from the Bayesian inference of each disk parameter to analyse the structural properties. Results. We detected 12 Class II brown dwarfs with Herschel, which corresponds to one-third of all currently known brown dwarf members of ρ Ophiuchi. We did not detect any of the known Class III brown dwarfs. Comparison to models reveals that the disks are best described by an inner radius between 0.01 and 0.07 AU, and a flared disk geometry with a flaring index between 1.05 and 1.2. Furthermore, we can exclude values of the disk scale-height lower than 10 AU (measured at a fiducial radius of 100 AU). We combined the Herschel data with recent ALMA observations of the brown dwarf GY92 204 (ISO-Oph 102), and by comparing its SED to the same grid of disk models, we derived an inner disk radius of 0.035 AU, a scale height of 15 AU with a flaring index of β ~ 1.15, an exponent for dust settling of-1.5, and a disk mass of 0.001 M{\^a}Š™. This corresponds to a disk-to-central object mass ratio of ~1{\%}. Conclusions. The structural parameters constrained by the extended SED coverage (inner radius and flaring index) show a narrow distribution for the young brown dwarfs detected in ρ Ophiuchi, suggesting that these objects share the same disk evolution and, perhaps, formation.",
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AU - Pinte, C.

AU - Kiss, C.

AU - Kun, M.

AU - Kóspál, A.

AU - André, P.

AU - Könyves, V.

PY - 2013

Y1 - 2013

N2 - Context. Young brown dwarfs are known to possess circumstellar disks, a characteristic that is fundamental to the understanding of their formation process, and raises the possibility that these objects harbour planets. Aims. We want to characterise the far-IR emission of disks around the young brown dwarf population of the ρ Ophiuchi cluster in LDN 1688. Methods. Recent observations of the ρ Ophiuchi cluster with the Herschel Space Observatory allow us to probe the spectral energy distribution (SED) of the brown dwarf population in the far-IR, where the disk emission peaks. We performed aperture photometry at 70, 100, and 160 μm, and constructed SEDs for all previously known brown dwarfs detected. These were complemented with ancillary photometry at shorter wavelengths. We compared the observed SEDs to a grid of synthetic disks produced with the radiative transfer code MCFOST, and used the relative figure of merit estimated from the Bayesian inference of each disk parameter to analyse the structural properties. Results. We detected 12 Class II brown dwarfs with Herschel, which corresponds to one-third of all currently known brown dwarf members of ρ Ophiuchi. We did not detect any of the known Class III brown dwarfs. Comparison to models reveals that the disks are best described by an inner radius between 0.01 and 0.07 AU, and a flared disk geometry with a flaring index between 1.05 and 1.2. Furthermore, we can exclude values of the disk scale-height lower than 10 AU (measured at a fiducial radius of 100 AU). We combined the Herschel data with recent ALMA observations of the brown dwarf GY92 204 (ISO-Oph 102), and by comparing its SED to the same grid of disk models, we derived an inner disk radius of 0.035 AU, a scale height of 15 AU with a flaring index of β ~ 1.15, an exponent for dust settling of-1.5, and a disk mass of 0.001 M⊙. This corresponds to a disk-to-central object mass ratio of ~1%. Conclusions. The structural parameters constrained by the extended SED coverage (inner radius and flaring index) show a narrow distribution for the young brown dwarfs detected in ρ Ophiuchi, suggesting that these objects share the same disk evolution and, perhaps, formation.

AB - Context. Young brown dwarfs are known to possess circumstellar disks, a characteristic that is fundamental to the understanding of their formation process, and raises the possibility that these objects harbour planets. Aims. We want to characterise the far-IR emission of disks around the young brown dwarf population of the ρ Ophiuchi cluster in LDN 1688. Methods. Recent observations of the ρ Ophiuchi cluster with the Herschel Space Observatory allow us to probe the spectral energy distribution (SED) of the brown dwarf population in the far-IR, where the disk emission peaks. We performed aperture photometry at 70, 100, and 160 μm, and constructed SEDs for all previously known brown dwarfs detected. These were complemented with ancillary photometry at shorter wavelengths. We compared the observed SEDs to a grid of synthetic disks produced with the radiative transfer code MCFOST, and used the relative figure of merit estimated from the Bayesian inference of each disk parameter to analyse the structural properties. Results. We detected 12 Class II brown dwarfs with Herschel, which corresponds to one-third of all currently known brown dwarf members of ρ Ophiuchi. We did not detect any of the known Class III brown dwarfs. Comparison to models reveals that the disks are best described by an inner radius between 0.01 and 0.07 AU, and a flared disk geometry with a flaring index between 1.05 and 1.2. Furthermore, we can exclude values of the disk scale-height lower than 10 AU (measured at a fiducial radius of 100 AU). We combined the Herschel data with recent ALMA observations of the brown dwarf GY92 204 (ISO-Oph 102), and by comparing its SED to the same grid of disk models, we derived an inner disk radius of 0.035 AU, a scale height of 15 AU with a flaring index of β ~ 1.15, an exponent for dust settling of-1.5, and a disk mass of 0.001 M⊙. This corresponds to a disk-to-central object mass ratio of ~1%. Conclusions. The structural parameters constrained by the extended SED coverage (inner radius and flaring index) show a narrow distribution for the young brown dwarfs detected in ρ Ophiuchi, suggesting that these objects share the same disk evolution and, perhaps, formation.

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