YSES and WiSPIT

My former graduate student Dr. Alex Bohn led a survey for directly imaged exoplanets using the VLT instrument SPHERE, which is called the Young Sun Exoplanet Survey (YSES). It consists of a sample of 70 young stars (around 14 to 17 Myr old) from the Sco-Cen association that were first identified by Eric Mamajek and Mark Pecaut. Instead of deep exposures of 60 to 90 minutes, we take 2 minute images in two filters per star. We then use RDI and PCA with all the other stars in the survey to build a reference PSF for our target star.

YSES 1b and 1c

Looking through the first set of second epoch images, Alex discovered our first exoplanet companion, YSES 1b, a 14 Jupiter mass companion around a 1.0 Solar mass star (Bohn et al., 2020), and then whilst taking data to characterise YSES 1b, Alex discovered a more distant companion from YSES 1, and this is a 6 Jupiter mass exoplanet some 320au away from the star (Bohn et al., 2020).

YSES 2

The YSES survey announced the discovery of a second directly imaged exoplanet system (Bohn et al., 2021), this time with a 6 Jupiter mass exoplanet with a projected orbit of 115au. What’s interesting is that this was the second discovery when only a third of the stars have been observed for their second epoch observations, suggesting that we may well find more exoplanet systems in the rest of the survey.

A disk around Wray 15-788

One of the first discoveries from YSES was a circumstellar disk around the star Wray 15-788 (Bohn et al., 2019), showing detailed circumstellar structure and shadowing from the inner rings onto the outer rings. Future observations will constrain the nature of the ring material and the geometry of inner structures closer to the star.