Possible planet formation in the young, low-mass, multiple stellar system GG Tau A

Anne Dutrey (1, 2, 3, 4, 5) , E. Di Folco (1, 2, 3, 4, 5) , S. Guilloteau (1, 2, 3, 4, 5) , Y. Boehler (6) , Jeff Bary (7) , Tracy Beck (8) , Hervé Beust (9) , E. Chapillon (1, 10, 2, 3, 4, 5) , Fredéric Gueth (10) , J.-M. Huré (1, 2, 3, 4, 5) , A. Pierens (1, 2, 3, 4, 5) , Vincent Piétu (10) , Michal Simon (11) , Ya-Wen Tang (12)

1 AMOR 2014
2 OASU - Observatoire aquitain des sciences de l'univers
3 LAB - Laboratoire d'Astrophysique de Bordeaux [Pessac]
4 L3AB - Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux
5 UB - Université de Bordeaux
6 CRyA - Centro de Radioastronomia y Astrofisica
7 Department of Physics and Astronomy [Hamilton NY]
8 STSci - Space Telescope Science Institute
9 IPAG - Institut de Planétologie et d'Astrophysique de Grenoble
10 IRAM - Institut de RadioAstronomie Millimétrique
11 LBCM - Laboratoire de Biotechnologie et Chimie Marines
12 GIPSA-lab - Grenoble Images Parole Signal Automatique

The formation of planets around binary stars may be more difficult than around single stars1, 2, 3. In a close binary star (with a separation of less than a hundred astronomical units), theory predicts the presence of circumstellar disks around each star, and an outer circumbinary disk surrounding a gravitationally cleared inner cavity around the stars4, 5. Given that the inner disks are depleted by accretion onto the stars on timescales of a few thousand years, any replenishing material must be transferred from the outer reservoir to fuel planet formation (which occurs on timescales of about one million years). Gas flowing through disk cavities has been detected in single star systems6. A circumbinary disk was discovered around the young low-mass binary system GG Tau A (ref. 7), which has recently been shown to be a hierarchical triple system8. It has one large inner disk9 around the single star, GG Tau Aa, and shows small amounts of shocked hydrogen gas residing within the central cavity10, but other than a single weak detection11, the distribution of cold gas in this cavity or in any other binary or multiple star system has not hitherto been determined. Here we report imaging of gas fragments emitting radiation characteristic of carbon monoxide within the GG Tau A cavity. From the kinematics we conclude that the flow appears capable of sustaining the inner disk (around GG Tau Aa) beyond the accretion lifetime, leaving time for planet formation to occur there. These results show the complexity of planet formation around multiple stars and confirm the general picture predicted by numerical simulations.

Mots clés: Exoplanets

Domaines: Astrophysique [astro-ph]; Cosmologie et astrophysique extra-galactique [astro-ph.CO]

Anne Dutrey, E. Di Folco, S. Guilloteau, Y. Boehler, Jeff Bary, et al.. Possible planet formation in the young, low-mass, multiple stellar system GG Tau A. Nature, 2014, 514 (7524), pp.600-602. ⟨10.1038/nature13822⟩. ⟨hal-01078717v1⟩