# Periodic Eclipses of the Young Star PDS 110 Discovered with WASP and KELT Photometry

## TL;DR

The paper reports the discovery of periodic eclipses caused by circumstellar material around the young star PDS 110, suggesting a possible low-mass companion with a circum-secondary disc, based on photometric data from WASP and KELT.

## Contribution

First detection of periodic eclipses by circumstellar material around PDS 110, indicating a potential low-mass companion with a circum-secondary disc at ~2AU.

## Key findings

- Eclipses recur every 808 days with ~30% depth and 25-day duration.
- Eclipses are caused by a structure likely associated with a low-mass companion.
- Next eclipse predicted for September 2017, enabling further observational studies.

## Abstract

We report the discovery of eclipses by circumstellar disc material associated with the young star PDS 110 in the Ori OB1a association using the SuperWASP and KELT surveys. PDS 110 (HD 290380, IRAS 05209-0107) is a rare Fe/Ge-type star, a ~10 Myr-old accreting intermediate-mass star showing strong infrared excess (L$_{\rm IR}$/L$_{\rm bol}$ ~ 0.25). Two extremely similar eclipses with a depth of ~30\% and duration ~25 days were observed in November 2008 and January 2011. We interpret the eclipses as caused by the same structure with an orbital period of $808\pm2$ days. Shearing over a single orbit rules out diffuse dust clumps as the cause, favouring the hypothesis of a companion at ~2AU. The characteristics of the eclipses are consistent with transits by an unseen low-mass (1.8-70M$_{Jup}$) planet or brown dwarf with a circum-secondary disc of diameter ~0.3 AU. The next eclipse event is predicted to take place in September 2017 and could be monitored by amateur and professional observatories across the world.