PDS 110 is a young star still approaching the main sequence. It has been classified as a T Tauri star,[6] or as a pre-main sequence star.[5] The emission lines indicative of a T Tauri classification are somewhat weaker than a typical T Tauri star, interpreted as a post-T Tauri stage.[5]
Brightness measurements from SuperWASP and KELT showed two similar reductions in brightness in November 2008 and January 2011, both with a maximal luminosity reduction of 30% and a duration of 25 days. These events were interpreted as transits of a structure with a period of 808 ± 2 days, corresponding to an orbital distance of about 2 AU. The large reduction in brightness could have happened due to a planet or brown dwarf with a circum-secondary disk of dust with a radius of 0.3 AU around a central object with a mass between 1.8 and 70 times the mass of Jupiter.[3]
Another transit was predicted for September 2017,[3] but nothing similar to the previous events was seen, ruling out a periodic event.[7] A search of 50 years of archival data also did not find any similar eclipses. The eclipses may have been caused by dust around PDS 110 itself. Larger-scale aperiodic dimmings have been observed as UX Orionis variables, and PDS 110 may be similar.[4]
An independent 2021 study, assuming that the eclipses were caused by a ringed object in orbit around the star, attempted to constrain the properties of such an object, with their preferred solution being a >35MJ brown dwarf on a nearly circular orbit. However, this does not explain the fact that no eclipse was observed in 2017.[8]
^Miroshnichenko, A. S.; Gray, R. O.; Vieira, S. L. A.; Kuratov, K. S.; Bergner, Yu. K. (1999). "Observations of recently recognized candidate Herbig Ae/Be stars". Astronomy and Astrophysics. 347: 137. Bibcode:1999A&A...347..137M.