C / 2013 US10 (Catalina)

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C / 2013 US10 (Catalina) [i]
Properties of the orbit ( animation )
Epoch:  7th August 2015 ( JD 2,457,241.5)
Orbit type hyperbolic
Numerical eccentricity 1,00031
Perihelion 0.823 AU
Inclination of the orbit plane 148.9 °
Perihelion 15th November 2015
Orbital velocity in the perihelion 38.2 km / s
history
Explorer Catalina Sky Survey
Date of discovery October 31, 2013
Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . Please also note the note on comet articles .

C / 2013 US10 (Catalina) was the (almost freiäugig visible) "Christmas Komet" 2015/16. It was discovered at the end of 2013 in the course of the Catalina Sky Survey , a search program for orbiting asteroids. The very faint object (around 20 mag) found on October 31, 2013 was initially classified as an asteroid under the designation 2013 US10. A coma soon appeared , so that it was reclassified as a comet as C / 2013 US10 (Catalina), and that it had already been recorded by Pan-STARRS in August 2013 .

Already in 2014 predictions showed that Catalina would be a beautiful binocular object for Central Europe for a few weeks around the turn of the year 2015/2016.

Path and brightness development

Its apparent brightness increased to 14th magnitude by October 2014, to 10 mag in June 2015 and to 6.5 mag at the end of August, but then remained almost constant. October not. In photos from July 27, 2015, a gas tail and a short dust tail appeared for the first time , but in October it was no longer observable due to the proximity to the sun. It was not until November 19, 2015 that the tail star could be photographed in the early morning sky near the horizon; unexpectedly, the brightness had hardly increased.

When Catalina's conjunction with the morning star Venus on December 7, 2015, the two tails, which were far apart for perspective reasons, appeared richly structured in photos.

On December 11th, the gas tail tore apart and on December 17th, at 8.4 degrees, it was the longest tail length to date. At the New Year he passed the bright Arcturus and passed the drawbar of the Big Dipper on January 15th.

Up to the time of perigee (proximity to the sun) on January 17th, the brightness only rose to 5.5 mag - so only visible for good eyes, but worth seeing in binoculars. For Central Europe it was close to the zenith in the evening sky , but freely-eyed only as a small nebula.

Important positions

  • November 15, 2015: Perihelion with 0.8 AU , but 1.7 AU to Earth. Elongation 14 ° in the southern sky in the constellation Libra
  • December 17, 2015: ascending knot (equatorial passage) with 1.0 AU from the sun, 1.2 AU to the earth, elongation 54 ° in the constellation Virgo
  • January 17, 2016: Close to the earth at a distance of 0.73 AU, 1.4 AU from the sun, favorable elongation of 108 ° in the northern sky , between the constellations Big Dipper and Hounds
  • January 31, 2016: northernmost orbit point at 81 ° north , elongation 116 ° in the constellation Giraffe
  • February 26, 2016: Declination sinks below + 60 ° (at RA = 4h 10m), comet is now visible again in the tropics
  • March 23 and 28, 2016: Passing by the open star clusters NGC 1528 and NGC 1545 , both with 6.5 may be a bit brighter than the comet.

See also

swell