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2004 Annual Science Report

University of California, Los Angeles Reporting  |  JUL 2003 – JUN 2004

Oceans and Kuiper Belts in Extrasolar Planetary Systems

4 Institutions
3 Teams
0 Publications
0 Field Sites
Field Sites

Project Progress

Our project on identifying asteroid belts and comets around other stars has moved forward on two fronts:

1) When a main sequence star evolves into a red giant and its Kuiper Belt objects

(KBOs) reach a temperature of ~170 K, the dust released during the rapid ice sublimation of these cometary bodies may lead to a detectable infrared excess at 25 microns, depending on the mass of the KBOs. Analysis of Infrared Astronomy Satellite (IRAS) data for 66 first-ascent red giants within 150 pc of the Sun provides an upper limit to the mass in KBOs at 45 AU orbital radius that is usually less than ~0.1 M(Earth). With improved infrared data, we may detect systems of KBOs around first-ascent red giants that are analogs to our solar system. (Jura, M. 2004, Astrophysical Journal, 603, 729. "Other Kuiper Belts")

2) The increase with time in the luminosity of a main-sequence star can eventually lead to substantial evaporation of the oceans on an orbiting terrestrial planet. Subsequently, the gas-phase H2O in the planet’s upper atmosphere can be photodissociated by stellar ultraviolet, and the resulting atomic hydrogen then may be lost in a wind. This gaseous envelope may pass in front of the host star and produce transient, detectable ultraviolet absorption in the Lyman lines in systems older than 1 Gyr. (Jura, M. 2004, Astrophysical Journal, 605, L65. "An Observational Signature of Evolved Oceans on Extrasolar Terrestrial Planets.")

    Michael Jura Michael Jura
    Project Investigator
    Objective 1.1
    Models of formation and evolution of habitable planets

    Objective 1.2
    Indirect and direct astronomical observations of extrasolar habitable planets