New studies released at the American Astronomical Society’s 45th Annual Division for Planetary Sciences meeting in Denver, Colorado suggests that Comet ISON could make it through its close perihelion passage near the Sun.
The first criterion for ISON to survive perihelion is its nucleus size. Comet nuclei smaller than 200 meters in diameter, with an average density or lower typically do not survive a close passage to the Sun. Observations from the Hubble Space Telescope, as well as smaller telescopes, suggest that ISON is between 1 and 4 kilometers across..
ISON may be just big and dense enough not to be vaporized and to survive its close encounter with the Sun. So it looks like ISON appears likely to survive the combination of mass loss due to sublimation and tidal disruption for most plausible scenarios.
ISON will pass inside the Roche limit of the Sun, which is a distance of 2.4 million kilometers with temperatures approaching 5,000 degrees Fahrenheit on closest approach. Comet ISON is expected to be the most active and put on its best showing post-perihelion – if it survives.
I was born in the 1960’s and have lived all my life in the Coal Mining Town of Barnsley in South Yorkshire, Northern England. My parents were all from this area of Yorkshire and my father worked in the main Industry of the local Collieries as a face worker. I have been married to my wife Debbie for 35+ years and we have two children and two grandchildren.
I have been licensed for around 20 years after my interest was re-kindled when I retired from my role as a Police Officer within South Yorkshire Police Force. The latter few years were spent as Radio Operator in the Force Operations Control Room at Sheffield, before my career ended.
IOTA chasing is (and always has been) my real passion, as climbing the ladder to reach Honour Roll status was always my main aim. The 1000 Islands Trophy is still out of reach but I am heading in the right direction. I am currently a Board Member of IOTA Ltd and IREF.
In my free time I am a keen Photographer of Wildlife, Aviation, (anything really) but the QSL Manager role is my main passion within Ham Radio.