C/2013 US₁₀ (Catalina)

C/2013 US10 as seen on 9 Dec 2015. To the upper left is theion gas tail and to the lower right is the dust tail.
Discovery
Discovered by	Catalina Sky Survey (703)[1][2]
Discovery date	31 October 2013
Orbital characteristics
Epoch	4 December 2015[3]
Observation arc	4.26 years
Number of observations	4396
Orbit type	Oort cloud
Aphelion	~38000AU (inbound)[4]
Perihelion	0.8229AU (q)[3]
Eccentricity	1.0003[3] 1.000+ (heliocentric epoch 2475–2500)[5]
Orbital period	several million years inbound (barycentric solution forepoch 1950)[4] Ejection trajectory outbound (barycentric solution for epoch 2050)[4]
Inclination	148.87°[3]
Last perihelion	15 November 2015[3]
JupiterMOID	1.13 AU

C/2013 US₁₀ (Catalina) is anOort cloudcomet discovered on 31 October 2013 by theCatalina Sky Survey at anapparent magnitude of 19 using a 0.68-meter (27 in)Schmidt–Cassegrain telescope.^[1] From September 2015 to February 2016 the comet was aroundapparent magnitude 6.^[6] The comet took around a million years to complete half an orbit from its furthest distance in the Oort cloud and should be ejected from the Solar System over many millions of years.

When discovered on 31 October 2013 observations from another object from 12 September 2013 were used in the preliminaryorbit determination giving an incorrect solution that suggested anorbital period of only 6 years.^[1] But by 6 November 2013 a longerobservation arc from 14 August until 4 November made it apparent that the first solution had the wrong object from 12 September.^[2]

By early May 2015 the comet was aroundapparent magnitude 12 and had anelongation of 60 degrees from the Sun as it moved further into theSouthern Hemisphere.^[7] The comet came tosolar conjunction on 6 November 2015 when the comet was around magnitude 6.^[6] The comet came toperihelion (closest approach to the Sun) on 15 November 2015 at a distance of 0.82 AU from the Sun.^[3] At perihelion, it had a velocity of 46.4 km/s (104,000 mph) with respect to the Sun which is slightlygreater than the Sun's escape velocity at that distance. It crossed thecelestial equator on 17 December 2015 becoming aNorthern Hemisphere object. On 17 January 2016 the comet passed 0.72 AU (108,000,000 km; 67,000,000 mi) from Earth and was around magnitude 6^[6] while located in theconstellation ofUrsa Major.^[8]

C/2013 US₁₀ is dynamically new. It came from theOort cloud with a loosely bound chaotic orbit that was easily perturbed bygalactic tides andpassing stars. Before entering the planetary region (epoch 1950),C/2013 US₁₀ had an orbital period of several million years.^[4] After leaving the planetary region (epoch 2050), it will be on anejection trajectory.^[4] TheSun's escape velocity at 200 AU is 2.98 km/s^[9] and the comet will be going 3.0 km/s at 200 AU from the Sun.^[10]

• 
  CometC/2013 US₁₀ (Warsaw, Poland; 10 January 2016, 02:51 UT+1)
• 
  C/2013 US₁₀ imaged on 6 December 2015
• 
  C/2013 US₁₀ imaged on 6 December 2015 (black and white)

Wikimedia Commons has media related toC/2013 US10 (Catalina).

• C/2013 US10 at theJPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit viewer · Orbit parameters · Physical parameters
• C/2013 US10 (Catalina) at CometBase
• Forbes - Comet Catalina To Pass By Earth For The Final TimeArchived 11 February 2017 at theWayback Machine
• NASA Astronomy Picture of the Day: Announcing Comet Catalina (18 August 2015)

• Non-periodic comets
• Hyperbolic comets
• Astronomical objects discovered in 2013
• Comets in 2013
• Comets in 2015
• Oort cloud

• Articles with short description
• Short description matches Wikidata
• Use dmy dates from September 2014
• Commons category link is on Wikidata
• JPL Small-Body Database ID same as Wikidata
• Webarchive template wayback links