A measure of the size of the magnetospheric accretion region in TW Hydrae
Artikel i vetenskaplig tidskrift, 2020
Stars form by accreting material from their surrounding disks. There is a consensus that matter flowing through the disk is channelled onto the stellar surface by the stellar magnetic field. This is thought to be strong enough to truncate the disk close to the corotation radius, at which the disk rotates at the same rate as the star. Spectro-interferometric studies in young stellar objects show that hydrogen emission (a well known tracer of accretion activity) mostly comes from a region a few milliarcseconds across, usually located within the dust sublimation radius1–3. The origin of the hydrogen emission could be the stellar magnetosphere, a rotating wind or a disk. In the case of intermediate-mass Herbig AeBe stars, the fact that Brackett γ (Brγ) emission is spatially resolved rules out the possibility that most of the emission comes from the magnetosphere4–6 because the weak magnetic fields (some tenths of a gauss) detected in these sources7,8 result in very compact magnetospheres. In the case of T Tauri sources, their larger magnetospheres should make them easier to resolve. The small angular size of the magnetosphere (a few tenths of a milliarcsecond), however, along with the presence of winds9,10 make the interpretation of the observations challenging. Here we report optical long-baseline interferometric observations that spatially resolve the inner disk of the T Tauri star TW Hydrae. We find that the near-infrared hydrogen emission comes from a region approximately 3.5 stellar radii across. This region is within the continuum dusty disk emitting region (7 stellar radii across) and also within the corotation radius, which is twice as big. This indicates that the hydrogen emission originates in the accretion columns (funnel flows of matter accreting onto the star), as expected in magnetospheric accretion models, rather than in a wind emitted at much larger distance (more than one astronomical unit).
Författare
R. Garcia-Lopez
Max-Planck-Gesellschaft
Dublin Institute for Advanced Studies
University College Dublin
A. Natta
Dublin Institute for Advanced Studies
A. Caratti o. Garatti
Dublin Institute for Advanced Studies
University College Dublin
Max-Planck-Gesellschaft
Tom Ray
Dublin Institute for Advanced Studies
Rubén Fedriani
Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik
Dublin Institute for Advanced Studies
M. Koutoulaki
European Southern Observatory (ESO)
Dublin Institute for Advanced Studies
L. Klarmann
Max-Planck-Gesellschaft
K. Perraut
Université Grenoble Alpes
J. Sanchez-Bermudez
Max-Planck-Gesellschaft
Universidad Nacional Autónoma de México
M. Benisty
Université Grenoble Alpes
Universidad de Chile (UCH)
C. Dougados
Université Grenoble Alpes
L. Labadie
Universität zu Köln
W. Brandner
Max-Planck-Gesellschaft
P. J. V. Garcia
European Southern Observatory Santiago
Instituto Superior Tecnico
Universidade do Porto
T. Henning
Max-Planck-Gesellschaft
P. Caselli
Max-Planck-Gesellschaft
G. Duvert
Université Grenoble Alpes
T. De Zeeuw
Universiteit Leiden
Max-Planck-Gesellschaft
R. Grellmann
Universität zu Köln
R. Abuter
European Southern Observatory (ESO)
A. Amorim
Instituto Superior Tecnico
Universidade de Lisboa
M. Bauböck
Max-Planck-Gesellschaft
J. P. Berger
European Southern Observatory (ESO)
Université Grenoble Alpes
H. Bonnet
European Southern Observatory (ESO)
A. Buron
Max-Planck-Gesellschaft
Y. Clénet
Université de recherche Paris Sciences et Lettres
V. Coudé Du Foresto
Université de recherche Paris Sciences et Lettres
W. J. De Wit
European Southern Observatory Santiago
A. Eckart
Universität zu Köln
Max-Planck-Gesellschaft
F. Eisenhauer
Max-Planck-Gesellschaft
M. Filho
Universidade do Porto
Instituto Superior Tecnico
European Southern Observatory Santiago
F. Gao
Max-Planck-Gesellschaft
C. E. Garcia Dabo
European Southern Observatory (ESO)
E. Gendron
Université de recherche Paris Sciences et Lettres
R. Genzel
University of California
Max-Planck-Gesellschaft
S. Gillessen
Max-Planck-Gesellschaft
M. Habibi
Max-Planck-Gesellschaft
X. Haubois
European Southern Observatory Santiago
F. Haussmann
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
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)
A. Ramirez
European Southern Observatory (ESO)
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. F. van Dishoeck
Universiteit Leiden
Max-Planck-Gesellschaft
F. H. 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
Julien Woillez
European Southern Observatory (ESO)
S. Yazici
Max-Planck-Gesellschaft
Universität zu Köln
G. Zins
European Southern Observatory Santiago
Nature
0028-0836 (ISSN) 1476-4687 (eISSN)
Vol. 584 7822 547-550Ämneskategorier
Meteorologi och atmosfärforskning
Fusion, plasma och rymdfysik
DOI
10.1038/s41586-020-2613-1