Planets are born in disks of gas that remain around young stars after their formation. These protoplanetary disks - also nicknamed "proplyds" - are gradually dispersed and evaporated over a period of one to ten million years by the radiation from their central star. In the 1990's, spectacular images of proplyds in the Orion Nebula where obtained by HST. Many of them had a cometary, or tadpole-like like, appearance, with their tails pointing away from the direction of the hot, massive star theta1C Ori. They were being evaporated by the intense UV radiaotion from this star. This raised the question of what would happen to protoplanetary disks in massive star forming regions, where, instead of just one or two massive O-type stars, there are tens or hundreds of them. The Cygnus OB2 association, at a distance of about 1.4 kpc, is our nearest massive star-forming region, containing at least 65 O-type stars. We have been studying this region over the last few years, using it as a labor20 edition of atory for understanding both star and planet formation. During this study, we discovered ten examaples of compact, nebulous objects on the periphery of the association that look like the Orion proplyds. They all have the tadpole shape with bright ionization fronts facing the massive O stars that are photoevaporating them, like that shown here, serendipitously caught in an earlier HST observation. They are larger that the Orion proplyds, but do appear to contain embedded young stars. Futher study of these objects will reveal more about how stars form in violent, massive star forming regions and whether or not planets can form in such a hostile environment. This work was lead by postdoc Nick Wright, now an RAS Fellow at the University of Hertfordshire, and was published in the 2012 February 20 edition of the Astrophysical Journal Letters. |
Recent research >