Abstract for Proposal 094035
Anticipated ToO of a pre-main sequence star undergoing an optical-IR outburst
Dramatic optical/IR outbursts from pre-main sequence (PMS) stars signal
the onset of rapid mass-infall onto such stars through their accretion
disks. Our X-ray ToO observations of such outbursts in V1647 Ori and
EX Lup demonstrate that a high accretion rate can also produce an X-ray
outburst, and, indeed, that X-ray observations of PMS accretion outbursts
represent a new observational window on the magnetic interaction between
the young star and its accretion disk. Additional X-ray observations of
accretion outbursts are needed to build a diverse sample of outbursting
PMS stars in order to investigate the star-disk magnetic interactions
producing the enhanced X-ray emission. Therefore, we propose a 60 ks
XMM-Newton ToO to observe any new optical/IR outburst from a PMS star.
Details on Observing Strategy and Trigger Criteria
We will trigger the proposed ToO after the report (via, e.g., ATel or
community brokers) of a new optical/IR outburst with delta V>2 mag from
a PMS star that is: (a) without close companion to avoid any confusion;
and (b) either located within ~400 pc or detected by Swift with >1.7
XRT PC count/ks to collect enough counts. The required reaction time
is 8 days. OM will be used in fast mode for a sequence of 13V or, if
the target is not too embedded, VB10VB (2 OM filter wheel rotations)
to detect a change in optical extinction.