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 L12Subject Categories
Meteorology and Atmospheric Sciences
Astronomy, Astrophysics and Cosmology
Atom and Molecular Physics and Optics
DOI
10.1051/0004-6361/202037583