Spitzer Space Telescope - Directors Discretionary Time Proposal #477


A Spitzer study of the extreme outburst of EX Lup

Principal Investigator: Peter Abraham
           Institution: Konkoly Observatory

     Technical Contact: Peter Abraham, Konkoly Observatory

Co-Investigators:
Thomas Henning, Max-Planck-Institut for Astronomie
Attila Juhasz, Max-Planck-Institut for Astronomie
Agnes Kospal, Konkoly Observatory
Attila Moor, Konkoly Observatory
Laszlo Mosoni, Konkoly Observatory
Nikoletta Sipos, Konkoly Observatory
Aurora Sicilia Aguilar, Max-Planck-Institut for Astronomie
Roy van Boekel, Max-Planck-Institut for Astronomie


Science Category: young stellar objects
Observing Modes: IrsStare MipsPhot MipsSed
Hours Approved: 0.9

Abstract:
EX Lupi is the prototype of EXors, a class of pre-main sequence eruptive variables
defined by their unpredictable brightenings which typically last several months.
Since 2008 January EX Lup is unusually bright and apparently entered a new outburst
period. It reached an extreme peak brightness of 8 mag, brighter than at any time
before. We propose to observe EX Lup during its most extreme eruption with the
Spitzer Space Telescope, in order tomeasure the 3.6-70 micrometer spectral energy
distribution and perform mid-infrared spectroscopy. Using the new Spitzer data we
will compare the quiescent and outburst states by analysing the wavelength-dependence
of the outburst and interpret the results in terms of disk temperature/density structure.
We will also analyse the silicate spectral features in order to look for the formation
of crystalline silicates, never seen in young eruptive stars before. We request 1.4 h
observing time for this program.