2/1/2021

Galaxies & Cosmology & Stars & Planets Seminar

Monday, February 1, 2021 - 11:00am

Zoom

The Mysterious Great Dimming of Betelgeuse

Speaker:

Andrea Dupree

Institution:

CfA

Visitor Schedule

Host:

Tatiana Niembro Hernandez

Abstract

The bright cool supergiant Betelgeuse became historically faint in February 2020. Various explanations have been offered for its unusual behavior – including conjectures this foreshadows an imminent supernova event. Direct imaging, spatially resolved spectroscopy, polarization measures, infrared, optical and ultraviolet spectra and more help to unravel what happened to the star. New ultraviolet spectroscopic observations with HST/STIS made with spatial resolution of the disk during the last months of 2020 are reported in advance of the next optical minimum expected in the spring of 2021.

Speckle Imaging of Exoplanet Host Stars

Speaker2:

Rachel Matson

Institution2:

US Naval Observatory

Visitor Schedule

Host2:

Rob Hargreaves

Abstract

Follow-up observations of exoplanet host star candidates from missions like Kepler & TESS are necessary to validate planets and characterize the host stars. High-resolution imaging is used to detect additional stars within the photometric aperture that may be responsible for the observed transit or dilute the planetary transit, causing the radius of the planet to be underestimated. The detection of nearby companions also allows us to study the relationship between binary stars and planet formation. With high-resolution speckle imaging we can detect stellar companions up to nine magnitudes fainter and within one arc second of planet candidate host stars. Using the separations and magnitude differences of the detected companions, we infer their periods and mass ratios and examine the distributions for insight into planet formation in binary systems.

Event Status:

Active

2/1/2021

Events