AAS 195th Meeting, January 2000
Session 103. The Importance of Comet Hale-Bopp: An Astronomical Perspective
Invited, Saturday, January 15, 2000, 8:30-9:20am, Centennial I and II

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[103.01] The Importance of Comet Hale-Bopp: An Astronomical Perspective

L.A. McFadden (U. Maryland)

Comet Hale-Bopp is repeatedly recounted in numerous scientific papers as the comet of the century. Extensive research has provided new insights into the cold and distant residual material of the solar nebula. Both technology and astute colleagues have created comparisons with other comets and with the chemistry of dust and gas in the interstellar medium. We have new insights into the dynamics and conditions of cometary processes and to conditions and chemistry that may have been set prior to incorporation of this matter into the solar nebula. A clearer picture of comets also allows us to understand the bodies that have shaped the surfaces of the planets over the past 4.6 b.y. Hale-Bopp was 11th magnitude at its discovery at r(h)=7.15 AU on July 23, 1995. It was a bright and distant comet compared to most recently discovered ones at 17-18th magnitude seen first inside of 4 AU. Hale-Bopp's brightness and early discovery permitted a long observation window that culminated at perihelion at 0.91 AU on 1 April, 1997 and continues today with the comet > 10 AU with a modelled total magnitude ~12.6. Its orbital elements establish that it is a long period comet that has passed through the solar system previously. Using several indirect image analysis techniques a diameter between 35-40 km is derived. Hale-Bopp is big by any standard of comet nucleus (Halley's triaxial diameters are 16x8x8 km). It was also active in terms of both dust and gas production, with numerous outbursts having been observed on both its inbound and outbound passage through the inner solar system. More than 50 observed molecules, radicals and ions have been observed some of which can be distinguished as presolar in origin. This work has been supported by NASA's NEAR and Deep Impact missions and U.Md.

If you would like more information about this abstract, please follow the link to http://www.astro.umd.edu/~mcfadden/halebopp. This link was provided by the author. When you follow it, you will leave the Web site for this meeting; to return, you should use the Back comand on your browser.

The author(s) of this abstract have provided an email address for comments about the abstract: mcfadden@astro.umd.edu

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