The long-wavelength view of GG Tau A: rocks in the ring world
The long-wavelength view of GG Tau A: rocks in the ring world
We present the first detection of GG Tau A at centimetre wavelengths, made with the Arcminute Microkelvin Imager Large Array at a frequency of 16 GHz (λ = 1.8 cm). The source is detected at >6 σrms with an integrated flux density of S16GHz = 249 ± 45 µJy. We use these new centimetre-wave data, in conjunction with additional measurements compiled from the literature, to investigate the long-wavelength tail of the dust emission from this unusual protoplanetary system. We use an MCMC-based method to determine maximum likelihood parameters for a simple parametric spectral model and consider the opacity and mass of the dust contributing to the microwave emission. We derive a dust mass of Md ~ 0.1 Msun, constrain the dimensions of the emitting region and find that the opacity index at λ > 7 mm is less than unity, implying a contribution to the dust population from grains exceeding ~4 cm in size. We suggest that this indicates coagulation within the GG Tau A system has proceeded to the point where dust grains have grown to the size of small rocks with dimensions of a few centimetres. Considering the relatively young age of the GG Tau association in combination with the low derived disc mass, we suggest that this system may provide a useful test case for rapid core accretion planet formation models.
radiation mechanisms: general, stars: formation, ISM: clouds, ISM: general
1139-1146
Scaife, A. M. M.
327b962f-9003-45ca-a6ea-284346c5cc85
October 2013
Scaife, A. M. M.
327b962f-9003-45ca-a6ea-284346c5cc85
Scaife, A. M. M.
(2013)
The long-wavelength view of GG Tau A: rocks in the ring world.
Monthly Notices of the Royal Astronomical Society, 435 (2), .
(doi:10.1093/mnras/stt1361).
Abstract
We present the first detection of GG Tau A at centimetre wavelengths, made with the Arcminute Microkelvin Imager Large Array at a frequency of 16 GHz (λ = 1.8 cm). The source is detected at >6 σrms with an integrated flux density of S16GHz = 249 ± 45 µJy. We use these new centimetre-wave data, in conjunction with additional measurements compiled from the literature, to investigate the long-wavelength tail of the dust emission from this unusual protoplanetary system. We use an MCMC-based method to determine maximum likelihood parameters for a simple parametric spectral model and consider the opacity and mass of the dust contributing to the microwave emission. We derive a dust mass of Md ~ 0.1 Msun, constrain the dimensions of the emitting region and find that the opacity index at λ > 7 mm is less than unity, implying a contribution to the dust population from grains exceeding ~4 cm in size. We suggest that this indicates coagulation within the GG Tau A system has proceeded to the point where dust grains have grown to the size of small rocks with dimensions of a few centimetres. Considering the relatively young age of the GG Tau association in combination with the low derived disc mass, we suggest that this system may provide a useful test case for rapid core accretion planet formation models.
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e-pub ahead of print date: 30 August 2013
Published date: October 2013
Keywords:
radiation mechanisms: general, stars: formation, ISM: clouds, ISM: general
Organisations:
Physics & Astronomy
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Local EPrints ID: 369362
URI: http://eprints.soton.ac.uk/id/eprint/369362
ISSN: 1365-2966
PURE UUID: 87a0ad89-dcb6-4053-a0ef-0ea8d5f6eb53
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Date deposited: 24 Sep 2014 13:32
Last modified: 14 Mar 2024 18:01
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Author:
A. M. M. Scaife
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