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Comet Hale-Bopp Fades
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Comet Hale-Bopp Fades |
| Explanation |
Comet Hale-Bopp has faded in the past few weeks. For Hale-Bopp [ http://newproducts.jpl.nasa.gov/comet/ ], promised as the Great Comet of 1997, this was a bit of a disappointment -- but not entirely unexpected. Comet Hale-Bopp [ http://antwrp.gsfc.nasa.gov/apod/ap960729.html ] continues to approach the Sun [ http://antwrp.gsfc.nasa.gov/apod/ap960916.html ] - making the comet itself brighten, but now the Earth [ http://antwrp.gsfc.nasa.gov/apod/ap960819.html ] is moving away from it - making the comet appear to dim. Experts disagree on just how bright Hale-Bopp [ http://encke.jpl.nasa.gov/hale_bopp_info.html ] will become. Optimists hope it will eventually outshine Comet Hyakutake [ http://antwrp.gsfc.nasa.gov/apod/lib/hyakutake.html ], but some pessimists now expect no better than 3rd magnitude - hardly visible from well-lit cities [ http://antwrp.gsfc.nasa.gov/apod/ap960617.html ]. Comet Hale-Bopp [ http://www.eso.org/comet-hale-bopp/ ] still appears to be, however, a very large comet, and is sure to show much activity as it nears the Sun. The comet should reach peak brightness in March 1997. [ http://newproducts.jpl.nasa.gov/comets/ephemjpl3.html ] This image [ http://www.eso.org/comet-hale-bopp/comet-hale-bopp-summary-sep13-96-rw.html ] was taken on August 18th and shows gas shed from the nucleus of the comet. |
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The Dust and Ion Tails of Co
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The Dust and Ion Tails of Comet Hale-Bopp |
| Explanation |
In 1997, Comet Hale-Bopp [ http://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_ts?Bopp ]'s "intrinsic" brightness exceeded any comet since 1811 [ http://cometography.com/lcomets/1811f1.html ]. Since it peaked on the other side of the Earth's orbit, however, the comet "appeared" only brighter than any comet in two decades [ http://cometography.com/lcomets/1975v1.html ]. Visible above are the two tails [ http://antwrp.gsfc.nasa.gov/apod/ap960502.html ] shed by Comet Hale-Bopp [ http://www.jpl.nasa.gov/comet/ ]. The blue ion tail [ http://www-spof.gsfc.nasa.gov/istp/events/halebopp/disconnect/ ] is composed of ionized [ http://csep10.phys.utk.edu/astr162/lect/light/ionization.html ] gas molecules, of which carbon monoxide [ http://www.cpsc.gov/cpscpub/pubs/466.html ] particularly glows blue when reacquiring electrons [ http://www-spof.gsfc.nasa.gov/Education/welect.html ]. This tail [ http://antwrp.gsfc.nasa.gov/htmltest/gifcity/comet.html ] is created by the particles from the fast solar wind [ http://antwrp.gsfc.nasa.gov/apod/ap000318.html ] interacting with gas from the comet's head. The blue ion tail [ http://antwrp.gsfc.nasa.gov/apod/ap970514.html ] points directly away from the Sun [ http://www.seds.org/nineplanets/nineplanets/sol.html ]. The light colored dust tail [ http://antwrp.gsfc.nasa.gov/apod/ap970403.html ] is created by bits of grit that have come off the comet's nucleus [ http://antwrp.gsfc.nasa.gov/apod/ap000805.html ] and are being pushed away by the pressure of light [ http://antwrp.gsfc.nasa.gov/apod/ap000526.html ] from the Sun. This tail points "nearly" away from the Sun. The above photograph [ http://www.celestialimage.com/page101.html ] was taken in March 1997. |
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