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Astrolecture Series - ExoComets: Now You See Them, Now You Don't

Tuesday, Dec 19, 07:30 PM - 09:00 PM At Presidio Officers' Club Offered by:

Presidio Trust

The AstroLecture Series is held every third Tuesday of the month and is co-sponsored by the San Francisco Amateur Astronomers in partnership with the Presidio Trust. Each lecture focuses on an astronomy related topic, and shares the latest findings and cutting edge science from noted professional astronomers, scientists, and scholars. Lectures introduce content that will engage the astronomy beginner as well as deliver a serious science fix to people with an advanced knowledge. One hour to 90 minutes of highly visual and stimulating presentation is followed by an interactive question and answer session. For all ages. Sponsored by the San Francisco Amateur Astronomers and the Presidio Trust.

At this Event

Dr. Barry Welsh will describe the attributes of comets in our solar system, including the techniques used to detect evaporating exocomets around young stars.

Minor bodies such as Kuiper Belt Objects, comets, and asteroids constitute the rocky, icy debris left over from the planet building phase of our solar system. The existence of reservoirs of small rocky bodies (i.e. asteroids/planetesimals) in orbit around young stellar systems is now well established. The initial protoplanetary disks that contain the reservoir of dust and gas required to form exoplanets are short lived (<<1Myr). The circumstellar debris disk observed around young stars of ages 10-50 Myr are continually replenished by collision and evaporation amongst planetesimals. The gravitational field can potentially enable large numbers of kilometer-sized icy bodies into trajectories directed toward the young central star. Using high resolution spectrographs mounted on large aperture ground based telescopes, we have discovered 15 young stars that harbor swarms of exocomets. This lecture will describe attributes of comets in our solar system, and observing techniques to detect evaporating exocomets around young stars. The relevance of Kepler's discovery of "Tabby's Star" will also be discussed.

 Dr. Barry Walsh received his PhD from University College of London, and studied Far IR Astronomy. Researched UV Astronomy and Instrumentation at London and Oxford University. Researched physics and early mapping of the Interstellar Medium at the Space Sciences Laboratory, UC Berkeley. He was project manager on UV detector systems for NASA SOHO, FUSE, GALEX and HST-COS missions. He is now discovering exocomet systems and carrying out a search for optical laser pulses from exoplanet systems.