Young stars grow just like kids: nothing happens for most of the time and then suddenly there’s a big spurt. We are publishing an article in this week’s issue of The Astrophysical Journal Letters where we present ALMA observations of such a recent burst of explosive stellar growth. The Niels Bohr Institute in Denmark, home of the article’s lead author, has issued a press release:
“We studied the chemistry of the gas and dust cloud surrounding the early protostar (an early stage of star formation). In this dense cloud, a chemical reaction takes place that enables the formation of several kinds of complex molecules, including methanol. One would expect that all of the molecules would be near the star, but with one of them we saw a clear ring structure. Something had removed a certain molecule, HCO+, from a wide area around the protostar,” explains astrophysicist Jes Jørgensen, Associate Professor at the Niels Bohr Institute and the Centre for Star and Planet Formation at the University of Copenhagen, Denmark.
“From the area where the HCO+ molecule has been dissolved by water vapour we can now calculate how bright the young star has been. It turns out that that the area is much greater than expected compared to the star’s current brightness. The protostar has been up 100 times brighter than the star is now. From the chemistry we can also say that this change happened within the last 100-1000 years – that is to say, very recently from an astronomical point of view.”