The GRAVITY young stellar object survey: IV. The CO overtone emission in 51 Oph at sub-au scales
Artikel i vetenskaplig tidskrift, 2021

Context. 51 Oph is a Herbig Ae/Be star that exhibits strong near-infrared CO ro-vibrational emission at 2.3 μm, most likely originating in the innermost regions of a circumstellar disc. Aims. We aim to obtain the physical and geometrical properties of the system by spatially resolving the circumstellar environment of the inner gaseous disc. Methods. We used the second-generation Very Large Telescope Interferometer instrument GRAVITY to spatially resolve the continuum and the CO overtone emission. We obtained data over 12 baselines with the auxiliary telescopes and derive visibilities, and the differential and closure phases as a function of wavelength. We used a simple local thermal equilibrium ring model of the CO emission to reproduce the spectrum and CO line displacements. Results. Our interferometric data show that the star is marginally resolved at our spatial resolution, with a radius of ∼10.58 ± 2.65R·. The K-band continuum emission from the disc is inclined by 63° ± 1°, with a position angle of 116° ± 1°, and 4 ± 0.8 mas (0.5 ± 0.1 au) across. The visibilities increase within the CO line emission, indicating that the CO is emitted within the dust-sublimation radius. By modelling the CO bandhead spectrum, we derive that the CO is emitted from a hot (T = 1900-2800 K) and dense (NCO = (0.9-9) × 1021 cm-2) gas. The analysis of the CO line displacement with respect to the continuum allows us to infer that the CO is emitted from a region 0.10 ± 0.02 au across, well within the dust-sublimation radius. The inclination and position angle of the CO line emitting region is consistent with that of the dusty disc. Conclusions. Our spatially resolved interferometric observations confirm the CO ro-vibrational emission within the dust-free region of the inner disc. Conventional disc models exclude the presence of CO in the dust-depleted regions of Herbig AeBe stars. Ad hoc models of the innermost disc regions, that can compute the properties of the dust-free inner disc, are therefore required.

Accretion, accretion disks

Stars: pre-main sequence

Stars: individual: 51 Oph

Stars: formation

Techniques: interferometric

Författare

M. Koutoulaki

Max-Planck-Gesellschaft

European Southern Observatory (ESO)

University College Dublin

Dublin Institute for Advanced Studies

R. Garcia-Lopez

University College Dublin

Max-Planck-Gesellschaft

Dublin Institute for Advanced Studies

A. Natta

Dublin Institute for Advanced Studies

Rubén Fedriani

University College Dublin

Dublin Institute for Advanced Studies

Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik, Galaktisk astrofysik

A. Caratti o. Garatti

Dublin Institute for Advanced Studies

Max-Planck-Gesellschaft

University College Dublin

T. P. Ray

Dublin Institute for Advanced Studies

Deirdre Coffey

Dublin Institute for Advanced Studies

Max-Planck-Gesellschaft

W. Brandner

Max-Planck-Gesellschaft

C. Dougados

Université Grenoble Alpes

P. J.V. Garcia

Instituto Superior Tecnico

Universidade do Porto

European Southern Observatory Santiago

L. Klarmann

Max-Planck-Gesellschaft

L. Labadie

Universität zu Köln

K. Perraut

Université Grenoble Alpes

J. Sanchez-Bermudez

Max-Planck-Gesellschaft

Universidad Nacional Autonoma de Mexico

C. C. Lin

University of Hawaii

Max-Planck-Gesellschaft

A. Amorim

Instituto Superior Tecnico

Universidade de Lisboa

M. Bauböck

Max-Planck-Gesellschaft

M. Benisty

Universidad de Chile (UCH)

Université Grenoble Alpes

J. P. Berger

Université Grenoble Alpes

A. Buron

Max-Planck-Gesellschaft

P. Caselli

Max-Planck-Gesellschaft

Y. Clénet

Université de recherche Paris Sciences et Lettres

V. Coudé Du Foresto

Université de recherche Paris Sciences et Lettres

P. T. De Zeeuw

Universiteit Leiden

Max-Planck-Gesellschaft

G. Duvert

Université Grenoble Alpes

W. J. De Wit

European Southern Observatory Santiago

A. Eckart

Max-Planck-Gesellschaft

Universität zu Köln

F. Eisenhauer

Max-Planck-Gesellschaft

M. Filho

Instituto Superior Tecnico

Universidade do Porto

European Southern Observatory Santiago

F. Gao

Max-Planck-Gesellschaft

E. Gendron

Université de recherche Paris Sciences et Lettres

R. Genzel

Max-Planck-Gesellschaft

University of California

S. Gillessen

Max-Planck-Gesellschaft

R. Grellmann

Universität zu Köln

M. Habibi

Max-Planck-Gesellschaft

X. Haubois

European Southern Observatory Santiago

F. Haussmann

Max-Planck-Gesellschaft

T. Henning

Max-Planck-Gesellschaft

S. Hippler

Max-Planck-Gesellschaft

Z. Hubert

Université Grenoble Alpes

M. Horrobin

Universität zu Köln

Alejandra Jimenez-Rosales

Max-Planck-Gesellschaft

L. Jocou

Université Grenoble Alpes

P. Kervella

Université de recherche Paris Sciences et Lettres

J. Kolb

European Southern Observatory Santiago

S. Lacour

Université de recherche Paris Sciences et Lettres

J. B. Le Bouquin

Université Grenoble Alpes

P. Léna

Université de recherche Paris Sciences et Lettres

H. Linz

Max-Planck-Gesellschaft

T. Ott

Max-Planck-Gesellschaft

T. Paumard

Université de recherche Paris Sciences et Lettres

G. Perrin

Université de recherche Paris Sciences et Lettres

O. Pfuhl

European Southern Observatory (ESO)

M. C. Ramírez-Tannus

Max-Planck-Gesellschaft

C. Rau

Max-Planck-Gesellschaft

G. Rousset

Université de recherche Paris Sciences et Lettres

S. Scheithauer

Max-Planck-Gesellschaft

J. Shangguan

Max-Planck-Gesellschaft

J. Stadler

Max-Planck-Gesellschaft

O. Straub

Max-Planck-Gesellschaft

C. Straubmeier

Universität zu Köln

E. Sturm

Max-Planck-Gesellschaft

E. Van Dishoeck

Max-Planck-Gesellschaft

Universiteit Leiden

F. Vincent

Université de recherche Paris Sciences et Lettres

S. von Fellenberg

Max-Planck-Gesellschaft

F. Widmann

Max-Planck-Gesellschaft

E. Wieprecht

Max-Planck-Gesellschaft

M. Wiest

Universität zu Köln

E. Wiezorrek

Max-Planck-Gesellschaft

S. Yazici

Max-Planck-Gesellschaft

Universität zu Köln

G. Zins

European Southern Observatory Santiago

Astronomy and Astrophysics

0004-6361 (ISSN) 1432-0746 (eISSN)

Vol. 645 A50

Ämneskategorier

Astronomi, astrofysik och kosmologi

Atom- och molekylfysik och optik

Geofysik

DOI

10.1051/0004-6361/202038000

Mer information

Senast uppdaterat

2021-01-20