A new study examines the potential conditions that result in strong infrared excess and H-alpha emissions from the M dwarf star, WISE J080822.18-644357.3. The paper explores whether or not the observations could indicate that the star is surrounded by a gaseous disk where accretion is actively occurring. M dwarf (or red dwarf) stars are small, cool, main sequence stars. It is not often that debris disks are spotted around M dwarfs, and no gas emissions have been observed from such stars.

Using the Atacama Large Millimeter/submillimeter Array (ALMA), astronomers looked at cold gas and dust properties of the star. No cold gas was detected, which rules out the possibility of a gas-rich disk. The strong infrared excess observed is also older than what would be expected from a typical planet-forming disk. The team believes that an optically thin dust disk could have resulted from the collisional cascades of large bodies (with radii larger than 16 au). Strong stellar winds could have then resulted in dust grains migrating inward from the outer disk by way of the Poynting–Robertson effect, which could explain the strong infrared excess observed.

The study, “The Planet Formation Potential Around a 45 Myr old Accreting M Dwarf,” was published in The Astrophysical Journal. The work was supported by the Nexus for Exoplanet System Science (NExSS). NExSS is a NASA research coordination network supported in part by the NASA Astrobiology Program. This program element is shared between NASA’s Planetary Science Division (PSD) and the Astrophysics Division.