Name: Prasanta Nayak
Affiliation: Tata Institute of Fundamental Research (TIFR) Mumbai
Conference ID : ASI2022_239
Title : UVIT/AstroSat study of T-Tauri Stars
Authors : Author (s): Prasanta K Nayak (1), Mayank Narang (1), Manoj Puravankara (1), Uma Gorti (2), Annapurni Subramaniam (3), Nayana George (4), Chayan Mondal (5) Affiliation (s): 1) TIFR Mumbai, 2) SETI/NASA Ames, 3) IIA Bangalore, 4) MG University Kerala, 5) IUCAA Pune
Abstract Type: Poster
Abstract Category : Stars, ISM and Galaxy
Abstract : T-Tauri stars (TTSs) are low-mass pre-main-sequence (PMS) stars. Accreting TTSs are known as Classical TTS (CTTS) and are characterized by strong H-alpha line emission and significant continuum excess emission in the ultra-violet (UV) and infra-red (IR) regions over photospheric values, whereas non-accreting disk-less TTSs are called weak-lines TTS (WTTS) as they show weak H-alpha emission. Emission from strong accretion shocks is thought to be the reason for the UV excess in CTTS, whereas comparatively low UV excess in WTTS is due to chromospheric activity. Another defining characteristic of TTS is that they show variability in line luminosities as well as in UV and optical continuum. The variations in UV line luminosities are also found to be correlated with variations in optical bands. The main source of variability is thought to be the change in accretion rate. The time scales of variability can be as short as a few hours to weeks, months, years, or longer. Though there have been many studies on TTS in optical and IR regions, their UV properties are relatively less studied despite the importance of UV photons in disk heating and influencing gas chemistry within the disk. I will present preliminary results from multiband photometric and FUV spectroscopic observations of young TTS and discuss what the UV properties of young stars can tell us about accretion and disk evolution. This will be the first UVIT study of TTS. I will also discuss the excellent capabilities of UVIT (in both photometry and spectroscopy) to study accretion variability in young TTS.