Comet Watch April 2018 with Special Guest Michelle Thaller Ph.D

April 8th, 2018 by Nick Evetts

Welcome to the April episode of Comet Watch featuring special guest, Michelle Thaller Ph.D  . My thanks, as always to my co-host Neil Norman!   Mary McIntyre is unwell and will be joining us again next month.

BAA Comet Section Visual Observations Page

Comet Lexell was discovered by Charles Mesier on June 14th,1770.
At this one and only apparition, it passed by Earth on its way to a August 14th perihelion, at a distance of 0.015 AU’s or 1,400,000 miles.
The comet was a member of the Jupiter family comets and originally had a perihelion distance of beyond 2 AU’s, but a close Jupiter approach by the comet in 1767 lead to its perihelion distance being radically changed . Comet Lexell holds the distinctions of being the first known JFC and also first NEO.
The comet again approached close to Jupiter in 1779 and the perihelion distance was increased greatly to some 3.3 AU’s.
The comet is today considered lost, but many still speculate that the comet was eventually expelled from the Solar System by Jupiter.
The debate continues………..

D/1770 L1 (Lexell)

Finding long lost Lexell’s comet: the fate of the first discovered near-earth object

Evolution of orbit of Lexell’s Comet

The Late Heavy Bombardment (abbreviated LHB and also known as the lunar cataclysm) is an event thought to have occurred approximately 4.1 to 3.8 billion years (Ga) ago, at a time corresponding to the Neohadean and Eoarchean eras on Earth.

Origin of the cataclysmic Late Heavy Bombardment period of the terrestrial planets


Asteroid Day


NEOShield Official Youtube channel

Northolt Branch Observatories

BAA Comet Section page 

BAA YouTube Channel

The Astronomer

The Astronomer  Youtube Channel

The German Comet Group

Seiichi Yoshida’s page

Liga Iberoamericana de Astronomia

Comet chasing

The Sky Live (Comets) 

Minor Planets Center (IAU)

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