An article published in “The Astrophysical Journal Letters” reports a research on the very young star SU Aurigae, or simply SU Aur, and on the protoplanetary disk around it. A team of researchers used new observations conducted with the SPHERE instrument on the VLT, combining them with old observations conducted with the NaCo instrument, also on the VLT, with the Hubble Space Telescope, and with the ALMA radio telescope to study the disk. It has a sort of tail of dust that comes from a nebula that is probably the result of a collision between the star and a cloud of gas and dust.
Just over 500 light-years from Earth, SU Aur is a very young star, estimated to be between 4 and 5 million years old. It hasn’t yet completed its formation process, and that already makes it interesting to study protostars that have yet to enter their main sequence, the stable phase in which a star spends most of its life. The disk of gas and dust that surrounds SU Aur represents another reason for interest and for this reason it has already been the subject of study in the past.
ESO’s VLT (Very Large Telescope) in Chile has already been used to observe SU Aur, for example with the NaCo instrument, which was decommissioned in 2019. It was actually a combination of two instruments and the name was in fact the contraction of the names of the Nasmyth Adaptive Optics System (NAOS) and the Near-Infrared Imager and Spectrograph (CONICA).
The Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) instrument, activated in June 2014, was used in a large observational program called the Disk Evolution Study Through Imaging of Nearby Young Stars (DESTINYS). This program has been carried out with a particular focus on a group of protoplanetary disks around stars with mass less than or equal to the Sun’s in star-forming regions in the cosmic neighborhood, within more or less 720 light-years from Earth.
The DESTINYS program also made it possible to obtain new observations of SU Aur, the most detailed of its protoplanetary disk. The researchers added the observations conducted with NaCo and others conducted with the Hubble Space Telescope and the ALMA (Atacama Large Millimeter/Submillimeter Array) radio telescope.
The image captured by SPHERE obscures the star because this instrument was specifically designed to directly observe exoplanets, so the star’s light must be blocked to allow far less bright objects to appear in the image. In the case of SU Aur, there are no planets formed yet, but there is a protoplanetary disk with an interesting dust tail.
According to the researchers, the tail is made up of dust coming from a nebula that is likely the result of a collision between the star and a cloud of gas and dust. That’s a star-forming region, so gas and dust tend to form more or less large clouds that can collide. In this case, gas and dust are still feeding materials to the SU Aur system. Understanding if this situation can create instability in the protoplanetary disk and the consequences on the planetary formation process represents a subject for future studies of this system.
SU Aur has also been studied in relation to another protostar existing in that area, AB Aurigae or AB Aur. The two of them could form a very wide binary system, and this makes it difficult to measure their possible orbits around each other. In short, these are really interesting systems to study the mechanisms of the formation of stars and planets.