(159857) 2004 LJ1

{{mp|2004 LJ|1}} is a member of the dynamical Apollo group, which are Earth-crossing asteroids. Apollo asteroids are the largest subgroup of near-Earth objects.

The body orbits the Sun at a distance of 0.9–3.6 AU once every 3 years and 5 months (1,244 days; semi-major axis of 2.26 AU). Its orbit has an eccentricity of 0.59 and an inclination of 23° with respect to the ecliptic. Its observation arc begins with a precovery from the Digitized Sky Survey taken at the Siding Spring Observatory, Australia, in February 1995, more than 9 years prior to its official discovery observation at Socorro.

With an absolute magnitude of at least 15.4, {{mp|2004 LJ|1}} is one of the brightest and presumably largest known potentially hazardous asteroid (see PHA-list). It has an Earth minimum orbital intersection distance of {{convert |0.0168 |AU |km |abbr=on |lk=off |sigfig=3}}, which translates into 6.5 lunar distances (LD). On 16 November 2038, this asteroid will make its closest near-Earth encounter at a nominal distance of 0.0198 AU (7.7 LD). It is also classified as a Mars-crosser, crossing the orbit of the Red Planet at 1.66 AU.

{{Large near earth asteroid flybys 10LD}}

{{mp|2004 LJ|1}} is an assumed stony S-type asteroid.

Three rotational lightcurves of {{mp|2004 LJ|1}} have been obtained from photometric observations by Johanna Torppa, Adrián Galád and Brian Warner since 2004.{{efn|name=lightcurve-plots-Warner}}{{efn|name=lcdb-Torppa-2011}} Lightcurve analysis gave a consolidated rotation period of 2.7247 hours with a brightness amplitude between 0.15 and 0.59 magnitude ({{small|U=3}}).

According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, {{mp|2004 LJ|1}} measures 3.07 kilometers in diameter and its surface has an albedo of 0.13. The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 2.47 kilometers, based on an absolute magnitude of 15.4.

This minor planet was numbered by the Minor Planet Center on 30 June 2007. As of 2018, it has not been named.

{{notelist|refs=

{{efn|name=lcdb-Torppa-2011|1=Torppa (2011) web: Undated observation. Rotation period {{val|2.76}} hours with a brightness amplitude of {{val|0.5}} mag. Quality Code of 2. Summary figures at the [http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=159857%7C LCDB]}}

{{efn|name=lightcurve-plots-Warner|1=[http://www.planetarysciences.org/plots/BDW/159857_2004LJ1_2014-06-25.PNG Lightcurve plot of {{mp|(159857) 2004 LJ|1}}] from June to July 2014, by B. D. Warner at the CS3–Palmer Divide Station in California ({{small|U82}}). Quality code of 2. Summary figures at the [http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=159857%7C LCDB] and [http://www.planetarysciences.org CS3 website].}}

}}

{{reflist|30em|refs=

{{cite web

|type = 2017-05-19 last obs.

|title = JPL Small-Body Database Browser: 159857 (2004 LJ1)

|url = https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2159857

|publisher = Jet Propulsion Laboratory

|accessdate = 18 January 2018}}

{{cite web

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|accessdate = 18 January 2018}}

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}}

• [http://www.minorplanet.info/PHP/lcdbsummaryquery.php Asteroid Lightcurve Database (LCDB)], query form ([http://www.minorplanet.info/lightcurvedatabase.html info] {{Webarchive|url=https://web.archive.org/web/20171216050541/http://www.minorplanet.info/lightcurvedatabase.html |date=16 December 2017 }})
• [https://books.google.com/books?id=aeAg1X7afOoC&pg Dictionary of Minor Planet Names], Google books
• {{NeoDys|159857}}
• {{ESA-SSA|159857|2004LJ1}}
• {{JPL small body|id=2159857}}

{{Minor planets navigator | |number=159857 |PageName={{mp|(159857) 2004 LJ|1}} | }}

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