(471240) 2011 BT15

Stony, sub-kilometer sized asteroid and fast rotator October 2019 yes (471240) 2011 BT 15 #FFC2E0 24 January 2011 Pan-STARRS Haleakala Obs. (471240) 2011 BT 15 NEOPHAApollo 4 September 2017 (JD 2458000.5) 0 9.63 yr (3,519 days) 1.6842 AU 0.9018 AU 1.2930 AU 0.3025 1.47 yr (537 days) 204.24° 0.6703 ms / day 1.6613° 105.37° 308.78° 0.0008 AU0.3 LD 0.136 km (calculated)0.150 km 4.9e9 kg (assumed) 0.109138 0.000002 h 0.20 (assumed) S 21.7 (471240) 2011 BT 15 is a stony, sub-kilometer sized asteroid and fast rotator, classified as a near-Earth object and potentially hazardous asteroid of the Apollo group. It had been one of the objects with the highest impact threat on the Palermo Technical Impact Hazard Scale. Discovery It was discovered on 24 January 2011, by a team of astronomers at Pan-STARRS, the Panoramic Survey Telescope and Rapid Response System at Haleakala Observatory on Hawaii, United States. The discovery was made using a 1.8-meter Ritchey–Chrétien telescope. At the time of discovery, the object had an apparent magnitude of 22. Orbit Before the 2013 recovery it had an observation arc of 41 days with an uncertainty parameter of 7. Due to precovery images from 2007 it now has an observation arc of more than 5 years. It makes close approaches to Earth and Mars. On 28 December 2013, it passed 0.03222 AU km on off 3 from Earth. The December 2013 passage was studied by the Goldstone Deep Space Network and further refined the orbit. Impact risk While listed on the Sentry Risk Table, virtual clones of the asteroid that fit the uncertainty region in the known trajectory showed a 1 in 71,000 chance that the asteroid could impact Earth on 5 January 2080. In 2013 it had the 5th highest impact threat on the Palermo Technical Impact Hazard Scale. It was removed from the Sentry Risk Table on 17 June 2013. With a 2080 Palermo Technical Scale of −3.58, the odds of impact by 2011 BT 15 in 2080 were about 3800 times less than the background hazard level of Earth impacts which is defined as the average risk posed by objects of the same size or larger over the years until the date of the potential impact. JPL Horizons shows that the nominal pass will be on 17 January 2080 at a distance of 0.125 AU km mi on on from Earth. Physical characteristics This near-Earth object is characterized as a common, stony S-type asteroid by the Collaborative Asteroid Lightcurve Link (CALL). Fast rotator In January 2014, a rotational lightcurve of 2011 BT 15 was obtained from photometric observations by American astronomer Brian Warner at the CS3-Palmer Divide Station (U82) in California. Lightcurve analysis gave a well-defined rotation period of 0.109138 hours (393 seconds) with a brightness amplitude of 0.61 magnitude (U=3). Diameter and albedo According to the CALL and JPL's impact-risk table, this near-Earth object measures 136 and 150 meters, respectively. For its size estimate, CALL uses a standard for stony asteroids of 0.20 with an absolute magnitude of 21.7. Naming As of 2017, this minor planet remains unnamed. References 30em 2017-03-18 last obs. JPL Small-Body Database Browser: 471240 (2011 BT15) https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2471240 Jet Propulsion Laboratory 2 June 2017 471240 (2011 BT15) Minor Planet Center https://www.minorplanetcenter.net/db_search/show_object?object_id=471240 24 April 2017 471240 24 April 2017 Warner, Brian D. July 2014 Near-Earth Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2014 January–March The Minor Planet Bulletin 41 3 157–168 32549046 7296834 1052-8091 2014MPBu...41..157W MPEC 2011-B43 : 2011 BT15 IAU Minor Planet Center 2011-01-27 https://minorplanetcenter.net/mpec/K11/K11B43.html 2013-01-10 (K11B15T) Earth Impact Risk Summary: 2011 BT15 Wayback Machine: NASA/JPL Near-Earth Object Program Office http://neo.jpl.nasa.gov/risk/2011bt15.html 2013-07-27 dead https://web.archive.org/web/20130218175502/http://neo.jpl.nasa.gov/risk/2011bt15.html February 18, 2013 (1.4e-05 = 1 in 71,000 chance) 10 Jan 2013 Sentry Risk Table Wayback Machine: NASA/JPL Near-Earth Object Program Office http://neo.jpl.nasa.gov/risk/ 2013-07-27 dead https://web.archive.org/web/20130110053551/http://neo.jpl.nasa.gov/risk/ January 10, 2013 Math: 103.58 = 3801 31 Aug 2005 The Palermo Technical Impact Hazard Scale NASA/JPL Near-Earth Object Program Office http://neo.jpl.nasa.gov/risk/doc/palermo.html https://web.archive.org/web/20020321092747/http://neo.jpl.nasa.gov/risk/doc/palermo.html dead 21 March 2002 2011-10-14 Horizons output JPL Horizons On-Line Ephemeris System http://ssd.jpl.nasa.gov/horizons.cgi?find_body=1&body_group=sb&sstr=2011BT15 Horizon Online Ephemeris System 2013-01-10 (Geocentric Solution) last observation: 2013-07-18; arc: 5.9 years JPL Close-Approach Data: (2011 BT15) https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2011BT15;cad=1#cad 2013-01-10 Date/Time Removed NASA/JPL Near-Earth Object Program Office http://neo.jpl.nasa.gov/risk/removed.html https://web.archive.org/web/20020602101400/http://neo.jpl.nasa.gov/risk/removed.html dead 2002-06-02 2013-07-27 2013-08-12 Goldstone Asteroid Schedule NASA/JPL Asteroid Radar Research Dr. Lance A. M. Benner http://echo.jpl.nasa.gov/asteroids/goldstone_asteroid_schedule.html 2013-08-16 External links Asteroid Lightcurve Database (LCDB), query form (info https://web.archive.org/web/20171216050541/http://www.minorplanet.info/lightcurvedatabase.html 16 December 2017 ) Dictionary of Minor Planet Names, Google books Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend 471240 471240 2011BT15 471240 (471240) 2011 BT 15 471240 471240 471240 471240 471240 471240 20110124