PREDNASAJUCI / LECTURER :

Ján Budaj

(1) Astronomical Institute, Slovak Academy of Sciences,
059 60 Tatranská Lomnica

NAZOV / TITLE :

A swarm of dusty objects in orbit around the central star of planetary nebula WeSb~1

ABSTRAKT / ABSTRACT :

Exoplanets and smaller bodies have been detected orbiting different kind of stars.
However, we do not know of any such objects in planetary nebulae (PNe),
the short-lived stage of stellar evolution between the asymptotic giant branch (AGB)
and white dwarf (WD) phases.
The planetary activity (destruction/formation) may be accompanied by dust clouds.
Hence, we searched for dust occultation events in PNe using archival photometric
data.
Here we show that the central star of PN WeSb~1 features numerous dimming events with
typical durations of a few days to weeks that are up to 3 magnitude deep. This
variability is mainly stochastic with an indication of a 400 d period.
The occultations are almost grey indicating dust grains larger than about 0.1 micron.
Based on our follow-up observations, we argue that the central star is a wide binary
and these events are most likely caused by debris from disintegrated small rocky bodies
that escaped from the former AGB star to find safe harbour around the companion star.
The latter star dominates the optical spectrum enabling us to see the eclipses.
This means that planetary systems are present and undergo violent evolution during
the PN stage.