Protostars and Planets VI, Heidelberg, July 15-20, 2013

Poster 1H035

YSOVAR: Variability in rho Oph

GŁnther, Hans Moritz (Harvard-Smithsonian Center for Astrophysics)
Poppenhaeger, K. (Harvard-Smithsonian Center for Astrophysics)
Wolk, S. J. (Harvard-Smithsonian Center for Astrophysics)
Rebull, L. M. (Spitzer Science Center / IPAC)
Plavchan, P. (Spitzer Science Center / IPAC)
Gutermuth, R. A. (Department of Astronomy, University of Massachusetts, Amherst, MA, USA)
YSOVAR collaboration, ()

Abstract:
Young stellar objects (YSOs) are intrinsically variable on a wide range of time scales and in almost all wavelength regions. In fact, YSOs were originally discovered by their optical variability. The sources observed in L1688 can be divided into several groups by their SED (class I, flat-spectrum (F), II and III) or by the properties of the lightcurve. We show examples of variable lightcurves as classified by the Stetson index (Stetson 1996), a c2 test and a period-finding algorithm. The time evolution for each source can be traced on the color-magnitude diagram and this allows us to distinguish variability caused by changes in accretion or extinction or by spots on the star. We show how the variability changes in the IR through different stages of YSO evolution. Since the L1688 cloud is near-by and much better studied compared to other clusters monitored by the YSOVAR project, we can take advantage of the reasonably complete membership list (Wilking et al. 2008) and present an almost complete census of the IR variability in a young cluster. We find that YSOs are variable in the mid-IR as long as they have disks (class I, F and II), but in the class II stage the variability is already much weaker. Most stars are variable due to variable extinction, but for young stars we also see variable accretion.

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