The outburst and nature of young eruptive low mass stars in dark clouds

J. P. Ninan1 ,D. K. Ojha1*,B. C. Bhatt2,K. K. Mallick 1, A. Tej3, D. K. Sahu2,S. K. Ghosh1 and V. Mohan4
1Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005, India
2CREST, Indian Institute of Astrophysics, Bengaluru 560 034, India
3Indian Institute of Space Science and Technology, Valiamala P.O., Thiruvananthapuram 695 547, India
4Inter-University Centre for Astronomy and Astrophysics, Post Bag 4, Ganeshkhind, Pune 411 007, India

View Full Article: [PDF]


The FU Orionis (FUor) or EX Orionis (EXor) phenomenon has attracted increasing attention in recent years and is now accepted as a crucial element in the early evolution of low-mass stars. FUor and EXor eruptions of young stellar objects (YSOs) are caused by strongly enhanced accretion from the surrounding disk. FUors display optical outbursts of ~ 4 mag or more and last for several decades, whereas EXors show smaller outbursts (∆m ~ 2 - 3 mag) that last from a few months to a few years and may occur repeatedly. Therefore, FUor/EXor eruptions represent a rare but very important phenomenon in early stellar evolution, during which a young low-mass YSO brightens by up to several optical magnitudes. Hence, longterm observations of this class of eruptive variables are important to design theoretical models of low-mass star formation. In this paper, we present recent results from our long-term monitoring observations of three rare types of eruptive young variables with the 2-m Himalayan Chandra Telescope (HCT) and the 2-m IUCAA Girawali Observatory (IGO) telescope.

  Next Article >>Back to Asics_Vol_004

Keywords : stars: formation – stars: pre-main-sequence – stars: variables: other – ISM: clouds – (ISM:) reflection nebulae