Good talk today from one of our own, Dr. Jackie Faherty, a Hubble fellow here at Carnegie.
Artist’s impression of the disc of dust and gas around a brown dwarf. From http://en.wikipedia.org/wiki/File:Artist%E2%80%99s_impression_of_the_disc_of_dust_and_gas_around_a_brown_dwarf.jpg.
Faherty talked about brown dwarfs (BD), a relatively new class of astronomical object that straddles the border between planets and stars. Brown dwarfs typically have masses between 13 and 75 times that mass of Jupiter and are made mostly of hydrogen gas, with lots of complex and interesting molecules mixed into their atmospheres.
Faherty studies the motion and distances of BDs using an age-old technique called parallax determination. It is very important to accurately estimate the distance for a BD because combining that estimate with measurements of a BD’s brightness and temperature gives a sense of the BD’s age — critical for understanding how BDs evolve over time.
BDs exhibit a bewildering variety of compositions and evolutionary behavior — some have variable clouds and weather — and the field is moving very rapidly. For example, astronomer Ian Crossfield just this year produced the first image of a BD’s atmosphere. And, in her talk, Faherty highlighted important similarities and differences between BDs and gas giant planets and showed how they may help unravel the mysteries of planet formation.