Astronomers from Kyushu University on Thursday announced that in the early stages of its growth, the “protostellar disc” that surrounds an infant star discharges plumes of dust, gas and electromagnetic energy in “sneezes” that can tell researchers a lot about them. All stars, including the Sun, are born in stellar nurseries, which are large concentrations of gas and dust. This gas and dust eventually coalesce to form a stellar core or a “baby star.” When this happens, some gas and dust can form a ring around the baby star, which is called a protostellar disc. "These structures are perpetually penetrated by magnetic fields, which brings with it magnetic flux. However, if all this magnetic flux were retained as the star developed, it would generate magnetic fields many orders of magnitude stronger than those observed in any known protostar," explained Kazuki Tokuda, lead author of a new study published in The Astrophysical Journal, in a press statement. To better understand this curious phenomenon, the researchers looked at MC 27, a stellar nursery that is located nearly 450 light-years away from the planet. They used observations collected by the ALMA array of high-precision radio telescopes in Chile. “As we analysed our data, we found something quite unexpected. There were these 'spike-like' structures extending a few astronomical units from the protostellar disk. As we dug in deeper, we found that these were spikes of expelled magnetic flux, dust, and gas. This is a phenomenon called 'interchange instability' where instabilities in the magnetic field react with the different densities of the gases in the protostellar disk, resulting in an outward expelling of magnetic flux. We dubbed this a baby star's 'sneeze' as it reminded us of when we expel dust and air at high speeds,” added Tokuda. They also saw other spikes a little far away from the protostellar disc and currently hypothesise that these could be other “sneezes” from the past. The researchers expect that sneezes could help them understand the complex processes of star formation that help shape the universe.
