"What kind of research has been conducted regarding calcium depletion and human spaceflight?"
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Seminar Detail
The Effect of Protoplanetary Disk Dispersal on Planet Formation
Presenter: David Hollenbach (NASA Ames Research Center)
February 4, 2008 11:00 AM Pacific
One of the first questions facing astrobiologists is: "What is the likelihood of habitable planets or moons forming around stars in the universe?" During their formation from gas and dust orbiting young stars, planets compete with mechanisms that disperse the gas and dust: viscous accretion on the central star and dispersal into interstellar space by the effects of nearby stellar encounters, the winds from the central star, and the ultraviolet (UV) and X-ray photons from either the central star or nearby luminous stars. We show with theoretical models validated by astronomical observations how viscous accretion likely dominates the dispersal in the inner regions (< 1 AU) of protoplanetary disks, while UV-induced photoevaporation dominates in the outer regions. These dispersal mechanisms may prevent, truncate, or otherwise affect planet formation and the resultant planetary architecture. Planetary formation is most seriously affected around high mass stars and around low mass stars in clusters of stars with high mass star members. We review progress made on answering the above question and future prospects.
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Without a Polycom...There are two ways to participate:
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2) You can watch the Realplayer webcast at: http://vanseg-1.arc.nasa.gov/2008/AB080204-01.ram and view the slides in WebEx (see WebEx instructions above) There is a 30 second delay for the webcast, so you will need to control the slides manually using the arrow buttons in WebEx. Questions for the speaker can be posted in the WebEx chat area to be answered at the end of the talk. Do not try to watch the Realplayer webcast at the same time as the Polycom or the phone.December 21, 2007
Team Overview Seminars: Each of the NAI teams will be giving one hour overview seminars that describe the work they will be performing as members of the NAI. These seminars, which will be broadcast via videoconference and web, will provide an opportunity to find out more about the science, EPO and other activities being performed by the NAI teams.
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