Accretion and outflow in the proplyd-like objects near Cygnus OB2

Abstract

Cygnus OB2 is the most massive association within 2kpc from the Sun, hosting hundreds of massive stars, thousands of young low mass members, and some sights of active star formation in the surrounding cloud. Recently, 10 photoevaporating proplyd-like objects with tadpole-shaped morphology were discovered in the outskirts of the OB association, approximately 6-14pc away from its center. The classification of these objects is ambiguous, being either evaporating residuals of the parental cloud which are hosting a protostar inside, or disk-bearing stars with an evaporating disk, such as the evaporating proplyds observed in the Trapezium Cluster in Orion. In this paper we present a study based on low resolution optical spectroscopic observations made with the Optical System for Imaging and low Resolution Integrated Spectroscopy (OSIRIS), mounted on the 10.4m Gran Telescopio CANARIAS (GTC), of two of these protostars. The spectrum of one of the objects shows evidence of accretion but not of outflows. In the latter object, the spectra show several emission lines indicating the presence of an actively accreting disk with outflow. We present estimates of the mass loss rate and the accretion rate from the disk, showing that the former exceeds the latter as observed in other known objects with evaporating disks. We also show evidence of a strong variability in the integrated flux observed in these objects, as well as in the accretion and outflow diagnostics.

Accepted in ApJ

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Cited by in corpus (9)

• The Massive Star Population of Cygnus OB2
• Proplyds around a B1 star - 42 Orionis in NGC 1977
• A Herschel view of protoplanetary disks in the $\sigma$ Ori cluster
• The influence of the environment on the spin evolution of low-mass stars. I. External photoevaporation of circumstellar disks
• External photoevaporation of protoplanetary discs: does location matter?
• Dispersal timescale of protoplanetary disks in the low-metallicity young cluster Dolidze 25
• Radio observations of evaporating objects in the Cygnus OB2 region
• Star formation in two irradiated globules around Cygnus OB2
• Star Forming Regions