Comet US10 Catalina: The Final Act

Comet US10 Catalina passes near the bright star Arcturus on January 1st. Image credit and copyright: Alan Tough

Have you seen it? 2016 has kicked off with a fine apparition of a binocular comet: C/2013 US10 Catalina. We’ve been following this icy visitor to the inner solar system the first few mornings of the year, a welcome addition to the morning planetary line-up.Astrophotographers have generated some amazing images Comet US10 Catalina as it glided past the bright star Arcturus on New Year’s Day through the constellation Boötes. We’ve written about the early stages of acts one and two back in 2015 for this fine comet; now, January 2016 sees the final act, a performance that finds this comet at its best for northern hemisphere observers this week into the next.First, the story thus far: Comet US10 Catalina was discovered on October 31st, 2013 during the routine Catalina Sky Survey sweeping the sky for comets and asteroids. The bizarre ‘US10′ designation speaks to the legacy of its original mis-designation as an asteroid, before its cometary nature became known.Comet US10 Catalina has an orbit that is inclined relatively high at 149 degrees (or 31 degrees, if its retrograde orbit isn’t accounted for) relative to the ecliptic. One of the stranger facts about comets is that their dust tail is blown back by the solar wind and always points away from the Sun… this means that the dust tail of a comet precedes it on its outbound leg, as Comet US10 Catalina is doing now. Visually, Comet US10 Catalina currently looks like an unresolved +6th magnitude globular cluster in binoculars, with just a hint of a spiky tail… deep sky images bring out a long graceful dust tail, with an opposing ion tail pushed back along the plane of the comet’s orbit.This week at it closest, Comet US10 Catalina will cross the constellation Canes Venatici —> Read More