VLA cm-wave survey of young stellar objects in the Oph A cluster: Constraining extreme UV- And X-ray-driven disk photoevaporation: A pathfinder for Square Kilometre Array studies
Journal article, 2019

Observations of young stellar objects (YSOs) in centimeter bands can probe the continuum emission from growing dust grains, ionized winds, and magnetospheric activity that are intimately connected to the evolution of protoplanetary disks and the formation of planets. We carried out sensitive continuum observations toward the Ophiuchus A star-forming region, using the Karl G. Jansky Very Large Array (VLA) at 10 GHz over a field-of-view of 6′ and with a spatial resolution of θmaj ×θmin ∼ 0.′′4 × 0.′′2. We achieved a 5 μJy beam-1 rms noise level at the center of our mosaic field of view. Among the 18 sources we detected, 16 were YSOs (three Class 0, five Class I, six Class II, and two Class III) and two were extragalactic candidates. We find that thermal dust emission generally contributed less than 30% of the emission at 10 GHz. The radio emission is dominated by other types of emission, such as gyro-synchrotron radiation from active magnetospheres, free-free emission from thermal jets, free-free emission from the outflowing photoevaporated disk material, and synchrotron emission from accelerated cosmic-rays in jet or protostellar surface shocks. These different types of emission could not be clearly disentangled. Our non-detections for Class II/III disks suggest that extreme UV-driven photoevaporation is insufficient to explain disk dispersal, assuming that the contribution of UV photoevaporating stellar winds to radio flux does not evolve over time. The sensitivity of our data cannot exclude photoevaporation due to the role of X-ray photons as an efficient mechanism for disk dispersal. Deeper surveys using the Square Kilometre Array (SKA) will have the capacity to provide significant constraints to disk photoevaporation.

Stars: formation

Protoplanetary disks

Radio continuum: stars

Stars: activity


A. Coutens

University of Bordeaux

H. B. Liu

European Southern Observatory (ESO)

I. Jimenez-Serra

Queen Mary University of London

T. L. Bourke

SKA Organisation

J. Forbrich

University of Hertfordshire

M. G. Hoare

University of Leeds

L. Loinard

Universidad Nacional Autónoma de México

L. Testi

Arcetri Astrophysical Observatory

European Southern Observatory (ESO)

M. Audard

University of Geneva

P. Caselli

Max Planck Society

A. Chacón-Tanarro

Spanish National Observatory (OAN)

C. Codella

Grenoble Alpes University

Arcetri Astrophysical Observatory

J. Di Francesco

National Research Council Canada

University of Victoria

Francesco Fontani

Arcetri Astrophysical Observatory

M. Hogerheijde

Leiden University

University of Amsterdam

A. Johansen

Lund University

D. Johnstone

National Research Council Canada

University of Victoria

S. Maddison

Swinburne University of Technology

O. Panić

University of Leeds

L. Perez

University of Chile (UCH)

L. Podio

Arcetri Astrophysical Observatory

A. Punanova

Ural Federal University

J. M.C. Rawlings

University College London (UCL)

D. Semenov

Ludwig Maximilian University of Munich (LMU)

Max Planck Society

M. Tazzari

University of Cambridge

J. J. Tobin

National Radio Astronomy Observatory

M. H. D. van der Wiel

Netherlands Institute for Radio Astronomy (ASTRON)

H. J. van Langevelde

Joint Institute for VLBI in Europe (JIVE)

University of Victoria

Wouter Vlemmings

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

C. Walsh

University of Leeds

D. J. Wilner

Harvard-Smithsonian Center for Astrophysics

Astronomy and Astrophysics

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

Vol. 631 A58

Subject Categories

Astronomy, Astrophysics and Cosmology

Atom and Molecular Physics and Optics

Fusion, Plasma and Space Physics


Onsala Space Observatory



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