2015A&A...574L...1C


Query : 2015A&A...574L...1C

2015A&A...574L...1C - Astronomy and Astrophysics, volume 574, L1-1 (2015/2-1)

Constraints on the gas content of the Fomalhaut debris belt. Can gas-dust interactions explain the belt's morphology?

CATALDI G., BRANDEKER A., OLOFSSON G., CHEN C.H., DENT W.R.F., KAMP I., ROBERGE A. and VANDENBUSSCHE B.

Abstract (from CDS):

The 440Myr old main-sequence A-star Fomalhaut is surrounded by an eccentric debris belt with sharp edges. This sort of a morphology is usually attributed to planetary perturbations, but the orbit of the only planetary candidate detected so far, Fomalhaut b, is too eccentric to efficiently shape the belt. Alternative models that could account for the morphology without invoking a planet are stellar encounters and gas-dust interactions. We aim to test the possibility of gas-dust interactions as the origin of the observed morphology by putting upper limits on the total gas content of the Fomalhaut belt. We derive upper limits on the CII 158µm and OI 63µm emission by using non-detections from the Photodetector Array Camera and Spectrometer (PACS) onboard the Herschel Space Observatory. Line fluxes are converted into total gas mass using the non-local thermodynamic equilibrium (non-LTE) code radex. We consider two different cases for the elemental abundances of the gas: solar abundances and abundances similar to those observed for the gas in the β Pictoris debris disc. The gas mass is shown to be below the millimetre dust mass by a factor of at least ∼3 (for solar abundances) respectively ∼300 (for β Pic-like abundances). The lack of gas co-spatial with the dust implies that gas-dust interactions cannot efficiently shape the Fomalhaut debris belt. The morphology is therefore more likely due to a yet unseen planet (Fomalhaut c) or stellar encounters.

Abstract Copyright:

Journal keyword(s): circumstellar matter - planetary systems - stars: individual: Fomalhaut - methods: observational - hydrodynamics - infrared: general

Simbad objects: 4

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Number of rows : 4
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 * 49 Cet PM* 01 34 37.7788265080 -15 40 34.898112472   5.667 5.607   5.54 A1V 256 0
2 * bet Pic PM* 05 47 17.0876901 -51 03 59.441135 4.13 4.03 3.86 3.74 3.58 A6V 1718 1
3 * alf PsA b Pl 22 57 39.04625 -29 37 20.0533           ~ 189 1
4 * alf PsA ** 22 57 39.04625 -29 37 20.0533 1.31 1.25 1.16 1.11 1.09 A4V 1146 3

    Equat.    Gal    SGal    Ecl

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2021.07.24-09:03:11

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