ALMA continuum observations of a 30 Myr old gaseous debris disk around HD 21997

A. Moór, A. Juhász, Á Kóspál, P. Ábrahám, D. Apai, T. Csengeri, C. Grady, Th Henning, A. M. Hughes, C. Kiss, I. Pascucci, M. Schmalzl, K. Gabányi

Research output: Article

28 Citations (Scopus)

Abstract

Circumstellar disks around stars older than 10 Myr are expected to be gas-poor. There are, however, two examples of old (30-40 Myr) debris-like disks containing a detectable amount of cold CO gas. Here we present Atacama Large Millimeter/Submillimeter Array (ALMA) and Herschel Space Observatory observations of one of these disks, around HD 21997, and study the distribution and origin of the dust and its connection to the gas. Our ALMA continuum images at 886 μm clearly resolve a broad ring of emission within a diameter of ∼4.″5, adding HD 21997 to the dozen debris disks resolved at (sub)millimeter wavelengths. Modeling the morphology of the ALMA image with a radiative transfer code suggests inner and outer radii of ∼55 and ∼150 AU, and a dust mass of 0.09 M. Our data and modeling hints at an extended cold outskirt of the ring. Comparison with the morphology of the CO gas in the disk reveals an inner dust-free hole where gas nevertheless can be detected. Based on dust grain lifetimes, we propose that the dust content of this gaseous disk is of secondary origin and is produced by planetesimals. Since the gas component is probably primordial, HD 21997 is one of the first known examples of a hybrid circumstellar disk, a thus-far little studied late phase of circumstellar disk evolution.

Original languageEnglish
Article numberL25
JournalAstrophysical Journal Letters
Volume777
Issue number2
DOIs
Publication statusPublished - nov. 10 2013

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debris
continuums
dust
gas
gases
planetesimal
modeling
radiative transfer
protoplanets
cold gas
rings
observatory
wavelength
observatories
stars
life (durability)
radii
wavelengths

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

ALMA continuum observations of a 30 Myr old gaseous debris disk around HD 21997. / Moór, A.; Juhász, A.; Kóspál, Á; Ábrahám, P.; Apai, D.; Csengeri, T.; Grady, C.; Henning, Th; Hughes, A. M.; Kiss, C.; Pascucci, I.; Schmalzl, M.; Gabányi, K.

In: Astrophysical Journal Letters, Vol. 777, No. 2, L25, 10.11.2013.

Research output: Article

Moór, A, Juhász, A, Kóspál, Á, Ábrahám, P, Apai, D, Csengeri, T, Grady, C, Henning, T, Hughes, AM, Kiss, C, Pascucci, I, Schmalzl, M & Gabányi, K 2013, 'ALMA continuum observations of a 30 Myr old gaseous debris disk around HD 21997', Astrophysical Journal Letters, vol. 777, no. 2, L25. https://doi.org/10.1088/2041-8205/777/2/L25
Moór, A. ; Juhász, A. ; Kóspál, Á ; Ábrahám, P. ; Apai, D. ; Csengeri, T. ; Grady, C. ; Henning, Th ; Hughes, A. M. ; Kiss, C. ; Pascucci, I. ; Schmalzl, M. ; Gabányi, K. / ALMA continuum observations of a 30 Myr old gaseous debris disk around HD 21997. In: Astrophysical Journal Letters. 2013 ; Vol. 777, No. 2.
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