title: PDS 110
text: # PDS 110
  
  PDS 110 is a young 11th magnitude star located approximately 1,090 light-years (335 pc) away in the constellation Orion. In 2017, it was discovered that the star is orbited by an exoplanet or brown dwarf with a disk of dust around it.
  
  ## Description
  
  PDS 110 is a young star still approaching the main sequence. It has been classified as a T Tauri star, or as a pre-main sequence star. 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.
  
  ## Dust disk around secondary object
  
  The PDS 110 planetary system :
  
  | Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (days) | Eccentricity | Inclination | Radius |
  | - | - | - | - | - | - | - |
  | b | 1.8-70 $M_J$ | 2 | 808 ± 2 | — | — | — |
  
  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. Another transit was predicted for September 2017, but nothing similar to the previous events was seen, ruling out a periodic event.
  
  