Planetary Science Research Discoveries

pdf version  PSRD-Hale-Bopp.pdf

HOT IDEAposted February 14, 1997

1997 Apparition of Comet Hale-Bopp
Written by Karen J. Meech
Institute for Astronomy,
University of Hawaii
Comets have both fascinated and frightened people throughout history, but few people outside the scientific community and a dedicated cadre of amateur observers pay attention to these celestial wanderers nowadays. This is largely due to our modern lifestyle in which the splendor of the night sky is rarely noticed. At any one time, there are a couple dozen comets which are accessible to astronomers and amateurs, but comets which can be appreciated by the general public are relatively rare. The unexpected discovery of comet C/1996 B2 (Hyakutake) provided excellent naked-eye observing opportunities during the spring of 1996, and another, comet C/1995 O1 (Hale-Bopp), may be even more spectacular this March and April.

In this issue of PSR Discoveries, we will discuss the importance of studying these small solar system bodies, including the historical development of cometary science, and will discuss the discovery and upcoming apparition of comet Hale-Bopp and how to best observe it.

Hot Idea Contents

History of Comets Historical Comet Observations. Comets have been the most feared celestial objects in history because of their sudden and sometimes bright appearance. When near the sun, comets can be the largest objects in the Solar System. To ancient peoples, they were interpreted as ill omens of impending disaster. This section briefly describes the role these celestial bodies have played historically.

Comet Science The Scientific Importance of Comets. Comets represent remnants from the early era of planet formation in our Solar System. By studying comets we have the opportunity to understand the physical and chemical conditions in the solar nebula, and this will give us insight into the process of planet formation. This is a particularly exciting area at the forefront of astronomical research since astronomers are finding evidence of extra-solar planetary systems.

Discovery of Comet Hale-Bopp Discovery of Comet Hale-Bopp. Comet C/1995 O1 (Hale-Bopp), was discovered independently on July 23, 1995 by Alan Hale (New Mexico) and Thomas Bopp (Arizona), and is the farthest comet discovered by amateurs. At the time of discovery it was magnitude 10.5 in the constellation of Sagittarius. At the time of discovery, the comet was 7.1 AU from the sun and 6.2 AU from Earth. The comet has been well observed since the time of its discovery, and a chronology of images is shown in this section.

Science from Bright Comets What We Can Learn from Bright Comets. While the appearance of an exceptionally bright comet is exciting for the general public, it provides unique observing opportunities for professional astronomers. Discoveries made from recent observations of comet Hyakutake illustrate the type of observations we hope to get with Hale-Bopp. Planned observations by several groups of research astronomers are also highlighted.

Observing Comet Hale-Bopp Observing Comet Hale-Bopp. Comet Hale-Bopp is not as well placed for observation as was comet Hyakutake. However, especially for people viewing from far North, the opportunities should be quite good. The comet makes its close Earth approach on March 22, and from Hawaii it will be visible in the early morning. The perihelion passage occurs on April 1, when the comet should be brightest, at which time the comet will be an early evening object. [Photo: R. Wainscoat]

Ephemeris Generators - includes sources for downloading ephemeris and finder chart software, as well as computed ephemerides for the comet.

Comet Hale-Bopp HomePages - list of alternate web sites for comet Hale-Bopp information ranging from amateur level discussions to research observations from national and international observatories.

Institute for Astronomy, Univ. of Hawaii - includes current images obtained from telescopes on Maunakea, Hawaii.

Honolulu's Bishop Museum Planetarium - includes information on programs and viewing opportunities in Hawaii.

Making a Comet in the Classroom - hands-on activity created by Dennis Schatz, Pacific Science Center.

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