David Pecker Conference Room, Willcox Hall, Pace University, Pleasantville,
or on-line via Zoom
(see home page for link and instructions for live attendance)

The Amazing Variability of T Tauri Stars
FRED WALTer
Department of Astronomy, SUNY Stony Brook

The T Tauri stars are young pre-main sequence stars of about Solar mass, with ages of a few million years. They are protostars – still collapsing from their natal dust clouds and not yet stably fusing Hydrogen in their cores. As indicated by the namesake of the class, these are variable stars. But all stars, including the Sun, are variable. What is so special about the T Tauri stars?

The talk will summarize some recent observations of pre-main sequence stars, motivated in large part by the high cadence, long term monitoring afforded by TESS, the Transiting Exoplanet Survey Satellite. Although designed to find exoplanet transits, TESS watches about 8% of the sky at any one time continuously for about 27 days, so it sees everything.

From above the atmosphere there are no day/night cycles, no weather to interrupt observations, and no twinkling except what the stars do on their own. TESS observations of stellar variability, coupled with ground-based spectroscopy, have given us fantastic new insights into the environments of these protostars.

Professor Walter has a PhD is in Astronomy from the University of California at Berkeley, has been teaching astronomy at Stony Brook University since 1989. He studies the birth and death of stars and stellar magnetic activity (stellar weather) using telescopes in Arizona, Chile, Hawaii, and in Earth orbit.