When you're just too small to be a star

by · Sep 19, 2013 · 2 863 views ·

The most massive planet is nearly 6 times lighter than the least massive star. In between is the realm of brown dwarfs. In 1995 both the first brown dwarf and the first exoplanet were discovered. Since then we have found hundreds of each, and have learned quite a bit. Recent infrared surveys have now probed the whole sky to very faint levels. Recent discoveries include the coolest and closest brown dwarfs. This allows us to push to very cool objects – the spectral sequence has added 3 to the original 7: L, T, and Y dwarfs. We can actually see brown dwarfs, whereas exoplanets are almost all detected only indirectly. Brown dwarfs overlap in temperature with young massive exoplanets, so their spectra look much more like planets than stars. I will give a flavor of how spectroscopy can be used to study what the atmospheres and physical properties of such objects are like. Gibor Basri has been a professor of Astronomy at UC Berkeley for more than 30 years. He is known as one of the discoverers of brown dwarfs, and an expert on low mass stars. In addition, he has contributed significantly to our understanding of star formation, and is now a member of the Kepler mission team which is searching for earth-sized exoplanets. Prof. Basri has employed telescopes ranging from nearby Lick Observatory to the mighty Keck telescopes on Mauna Kea to space-borne telescopes like Hubble and Kepler. He has been awarded a Miller Research Professorship, and Sigma Xi Distinguished Lectureship. Basri has over 200 publications and 10,000 citations to his work, and has given many public lectures and appeared on several television programs. He has long made promotion of science in underrepresented communities a mission, and is now the Vice Chancellor for Equity and Inclusion at Berkeley.

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