2015 XY261

Asteroid March 2019 yes 2015 XY 261 #FFC2E0 6 December 2015 Pan-STARRS 1(first observered) Haleakala Obs. 2015 XY 261 ApolloNEO 23 March 2018 (JD 2458200.5) 5 0.025 yr (9 days) 2.1890 AU 0.8003177 AU 1.4945093 AU 0.4644947 1.83 yr (667 days) 62.24896° 0.5394558 ms / day 1.59013° 86.91527° 61.94406° 0.00184 AU (0.72 LD) 9.7–22 meters 27.2 2015 XY 261 is an Apollo near-Earth asteroid that is also a Mars crosser. It is roughly 10–22 meters in diameter and passed less than 1 lunar distance, 0.0025696 AU km mi on from Earth on 15 December 2015. 2015 flyby This small dim asteroid approached Earth in opposition, having an elongation from the Sun of over 160 degrees from mid November 2015. However, due to its absolute magnitude even though it had a very low phase angle during the approach it was too dim for contemporary telescopes to spot it so early, as it was significantly fainter than apparent magnitude 23. However it got brighter as it approached and a few weeks later, on 6 December 2015 it was spotted by Pan-STARRS at an apparent magnitude of 21.5 using a 1.8 m in on us Ritchey–Chrétien telescope. On 15 December 2015 at 13:52 UT, the asteroid passed 0.0019277 AU km mi on on from the Earth and three and a half hours later at 17:17 UT passed 0.00354 AU km mi on off from the Moon. This flyby is notable because the discovery was 9 days prior to closest approach. This is one of the earliest discoveries of an asteroid during approach. Discounting cataloged objects which were discovered during previous orbits, most asteroids are discovered with little or no warning. 2015 XY 261 was the only asteroid to pass within 1 LD of Earth in 2015 that was discovered more than a week before closest approach. See List of asteroid close approaches to Earth in 2015. References 2015-01-29 last obs. JPL Small-Body Database Browser: (2015 XY261) http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2015+XY261 Jet Propulsion Laboratory 28 July 2018 2015 XY261 Minor Planet Center http://www.minorplanetcenter.net/db_search/show_object?object_id=2015+XY261 28 July 2018 MPEC 2015-X153: 2015 XY261 IAU Minor Planet Center 2015-01-30 http://minorplanetcenter.net/mpec/K15/K15XF3.html 28 July 2018 (K15Bp3P) last observation: 2015-01-29; arc: 10 days JPL Close-Approach Data: (2015 XY261) http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2015XY261;cad=1#cad 28 July 2018 Absolute Magnitude (H) NASA/JPL http://neo.jpl.nasa.gov/glossary/h.html https://web.archive.org/web/20010302182040/http://neo.jpl.nasa.gov/glossary/h.html dead 2 March 2001 28 July 2018 2015XY261 Ephemerides for 15 January 2015 through 1 February 2015 NEODyS (Near Earth Objects Dynamic Site) https://newton.spacedys.com/neodys/index.php?pc=1.1.3.1&n=2015XY261&oc=500&y0=2015&m0=1&d0=15&h0=0&mi0=0&y1=2015&m1=2&d1=1&h1=0&mi1=0&ti=3&tiu=hours 28 July 2018 External links 2015XY261 2015XY261 2015XY261 # Category:Minor planet object articles (unnumbered) 20150118 20150127