The GRAVITY young stellar object survey: II. First spatially resolved observations of the CO bandhead emission in a high-mass YSO
Journal article, 2020

Context. The inner regions of the discs of high-mass young stellar objects (HMYSOs) are still poorly known due to the small angular scales and the high visual extinction involved. Aims. We deploy near-infrared spectro-interferometry to probe the inner gaseous disc in HMYSOs and investigate the origin and physical characteristics of the CO bandhead emission (2.3-2.4 m). Methods. We present the first GRAVITY/VLTI observations at high spectral (R = 4000) and spatial (mas) resolution of the CO overtone transitions in NGC2024 IRS 2. Results. The continuum emission is resolved in all baselines and is slightly asymmetric, displaying small closure phases (8). Our best ellipsoid model provides a disc inclination of 34 1, a disc major axis position angle (PA) of 166 1, and a disc diameter of 3:99 0:09 mas (or 1.69 0.04 au, at a distance of 423 pc). The small closure phase signals in the continuum are modelled with a skewed rim, originating from a pure inclination effect. For the first time, our observations spatially and spectrally resolve the first four CO bandheads. Changes in visibility, as well as differential and closure phases across the bandheads are detected. Both the size and geometry of the CO-emitting region are determined by fitting a bidimensional Gaussian to the continuum-compensated CO bandhead visibilities. The CO-emitting region has a diameter of 2.740:08 0:07 mas (1.16 0.03 au), and is located in the inner gaseous disc, well within the dusty rim, with inclination and PA matching the dusty disc geometry, which indicates that both dusty and gaseous discs are coplanar. Physical and dynamical gas conditions are inferred by modelling the CO spectrum. Finally, we derive a direct measurement of the stellar mass of M 14:7 M by combining our interferometric and spectral modelling results.

Techniques: spectroscopic

Methods: observational

Infrared: stars

Techniques: interferometric

Stars: massive

Stars: formation

Author

A. Caratti o. Garatti

Dublin Institute for Advanced Studies

Max Planck Society

University College Dublin

Rubén Fedriani

Dublin Institute for Advanced Studies

University College Dublin

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

R. Garcia-Lopez

Max Planck Society

Dublin Institute for Advanced Studies

University College Dublin

M. Koutoulaki

Dublin Institute for Advanced Studies

University College Dublin

European Southern Observatory (ESO)

K. Perraut

Grenoble Alpes University

H. Linz

Max Planck Society

W. Brandner

Max Planck Society

P. J. V. Garcia

University of Porto

Instituto Superior Tecnico

European Southern Observatory Santiago

L. Klarmann

Max Planck Society

T. Henning

Max Planck Society

L. Labadie

University of Cologne

J. Sanchez-Bermudez

Max Planck Society

Universidad Nacional Autónoma de México

B. Lazareff

Grenoble Alpes University

E. F. van Dishoeck

Leiden University

Max Planck Society

P. Caselli

Max Planck Society

P. T. De Zeeuw

Max Planck Society

Leiden University

A. Bik

Stockholm University

M. Benisty

European Southern Observatory Santiago

Grenoble Alpes University

C. Dougados

Grenoble Alpes University

Tom Ray

Dublin Institute for Advanced Studies

A. Amorim

Instituto Superior Tecnico

J. P. Berger

Grenoble Alpes University

Y. Clénet

Paris Observatory

V. Coudé Du Foresto

Paris Observatory

G. Duvert

Grenoble Alpes University

A. Eckart

University of Cologne

F. Eisenhauer

Max Planck Society

F. Gao

Max Planck Society

E. Gendron

Paris Observatory

R. Genzel

University of California

Max Planck Society

S. Gillessen

Max Planck Society

P. Gordo

Instituto Superior Tecnico

L. Jocou

Grenoble Alpes University

M. Horrobin

University of Cologne

P. Kervella

Paris Observatory

S. Lacour

Paris Observatory

J. B. Le Bouquin

Grenoble Alpes University

P. Léna

Paris Observatory

R. Grellmann

University of Cologne

T. Ott

Max Planck Society

T. Paumard

Paris Observatory

G. Perrin

Paris Observatory

G. Rousset

Paris Observatory

S. Scheithauer

Max Planck Society

J. Shangguan

Max Planck Society

J. Stadler

Max Planck Society

O. Straub

Max Planck Society

C. Straubmeier

University of Cologne

E. Sturm

Max Planck Society

W. F. Thi

Max Planck Society

F. H. Vincent

Paris Observatory

F. Widmann

Max Planck Society

Astronomy and Astrophysics

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

Vol. 635 L12

Subject Categories

Meteorology and Atmospheric Sciences

Astronomy, Astrophysics and Cosmology

Atom and Molecular Physics and Optics

DOI

10.1051/0004-6361/202037583

More information

Latest update

5/19/2020