View source for Astronomy:(101869) 1999 MM

{{Infobox planet
 | minorplanet     = yes
 | name            = (101869) 1999 MM
 | background      = #FFC2E0
 | image           = 
 | image_size      = 
 | caption         = 
 | discovery_ref   = <ref name="jpldata" />
 | discovered      = 20 June 1999
 | discoverer      = [[Astronomy:Lowell Observatory Near-Earth-Object Search|LONEOS]]
 | discovery_site  = Anderson Mesa Stn.
 | mpc_name        = (101869) 1999 MM
 | alt_names       = 1999 MM
 | named_after     = 
 | mp_category     = {{nowrap|[[Astronomy:Apollo asteroid|Apollo]]{{·}}[[Astronomy:Near-Earth object|NEO]]{{·}}[[Astronomy:Potentially hazardous object|PHA]]<ref name="jpldata" /><ref name="MPC-object" />}}
 | orbit_ref       = <ref name="jpldata" />
 | epoch           = 4 September 2017 ([[Astronomy:Julian day|JD]] 2458000.5)
 | uncertainty     = 0
 | observation_arc = 8.67 yr (3,167 days)
 | aphelion        = 2.6168 [[Astronomy:Astronomical unit|AU]]
 | perihelion      = 0.6319 AU
 | semimajor       = 1.6243 AU
 | eccentricity    = 0.6110
 | period          = 2.07 [[Astronomy:Julian year|yr]] (756 days)
 | mean_anomaly    = 254.72[[Degree (angle)|°]]
 | mean_motion     = {{Deg2DMS|0.4761|sup=ms}} / day
 | inclination     = 4.7642°
 | asc_node        = 110.98°
 | arg_peri        = 268.77°
 | moid            = 0.0016 AU (0.6 [[Astronomy:Lunar distance|LD]])
 | mean_diameter   = 370–830 [[Metre|m]]<ref name="h" />
 | rotation        = 
 | albedo          = 
 | spectral_type   = 
 | abs_magnitude   = 19.3<ref name="jpldata" />
}}

'''{{mp|(101869) 1999 MM}}''' (provisional designation '''{{mp|1999 MM}}''') is a sub-kilometer [[Astronomy:Asteroid|asteroid]] on an eccentric orbit, classified as a [[Astronomy:Near-Earth object|near-Earth object]] and [[Astronomy:Potentially hazardous asteroid|potentially hazardous asteroid]] of the [[Astronomy:Apollo asteroid|Apollo group]]. It was discovered on 20 June 1999, by the Lowell Observatory Near-Earth-Object Search (LONEOS) at its U.S. Anderson Mesa Station in Flagstaff, Arizona. The first observation was made by [[Astronomy:Catalina Sky Survey|Catalina Sky Survey]] just 8 days before its official discovery.<ref name="MPC-object" />

== Orbit and classification ==

The asteroid orbits the Sun at a distance of 0.6–2.6&nbsp;[[Astronomy:Astronomical unit|AU]] once every 2 years and 1 month (756 days). Its orbit has an [[Astronomy:Orbital eccentricity|eccentricity]] of 0.61 and an [[Astronomy:Orbital inclination|inclination]] of 5[[Degree (angle)|°]] with respect to the [[Astronomy:Ecliptic|ecliptic]]. It has a notably low Earth [[Astronomy:Minimum orbit intersection distance|minimum orbit intersection distance]] of {{convert|0.0016|AU|km|abbr=on|lk=in}}, which is less than one [[Astronomy:Lunar distance|lunar distance]], and also approaches Mars and Venus to within 15 million kilometers.<ref name="jpldata" />

{{mp|1999 MM}}'s orbit is very similar to that of 69230&nbsp;Hermes, which in 1937 made what was for decades the closest observed approach to Earth by an asteroid. Its nearest pass to Earth within at least a century of present was the 930,000 kilometers one in 1875. In 2090 it passes Venus at 788,000 kilometers.

== Physical characteristics ==

Based on its [[Astronomy:Absolute magnitude#Solar System bodies (H)|absolute magnitude]] of 19.3,<ref name="jpldata" /> its mean-diameter is between 370 and 830 meters, assuming an [[Astronomy:Astronomical albedo|albedo]] in the range of 0.05 to 0.25.<ref name="h" />

== Numbering and naming ==

This [[Astronomy:Minor planet|minor planet]] was [[Astronomy:Minor planet designation|numbered]] by the [[Organization:Minor Planet Center|Minor Planet Center]] on 19 October 2005.<ref name="MPC-Circulars-Archive" /> As of 2018, it has not been [[Astronomy:List of named minor planets (alphabetical)|named]].<ref name="MPC-object" />

== References ==
{{reflist|30em|refs=

<ref name="jpldata">{{cite web
  |type       = 2008-02-12 last obs.
  |title      = JPL Small-Body Database Browser: 101869 (1999 MM)
  |url        = https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2101869
  |publisher  = [[Organization:Jet Propulsion Laboratory|Jet Propulsion Laboratory]]
  |accessdate = 1 June 2017}}</ref>

<ref name="MPC-object">{{cite web
  |title      = 101869 (1999 MM)
  |work       = [[Organization:Minor Planet Center|Minor Planet Center]]
  |url        = https://www.minorplanetcenter.net/db_search/show_object?object_id=101869
  |accessdate = 2 February 2018}}</ref>

<ref name="MPC-Circulars-Archive">{{cite web
  |title      = MPC/MPO/MPS Archive
  |work       = Minor Planet Center
  |url        = https://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html
  |accessdate = 24 February 2018}}</ref>

<ref name="h">{{cite web
  |title      = Asteroid Size Estimator
  |publisher  = CNEOS NASA/JPL
  |url        = https://cneos.jpl.nasa.gov/tools/ast_size_est.html
  |accessdate = 2 February 2018}}</ref>

}} <!-- end of reflist -->

== External links ==
* [https://www.minorplanetcenter.net/mpec/J99/J99M26.html MPEC from 1999 discovery]
* [https://www.minorplanetcenter.net/iau/mpec/K01/K01M19.html MPEC from 2001]
* [https://www.minorplanetcenter.net/iau/lists/NumberedMPs100001.html Discovery Circumstances: Numbered Minor Planets (100001)-(105000)] – ''Minor Planet Center''
* [https://www.minorplanetcenter.net/iau/lists/t_phas.html List of the Potentially Hazardous Asteroids (PHAs)], ''Minor Planet Center''
* [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 }})
* [http://obswww.unige.ch/~behrend/page_cou.html Asteroids and comets rotation curves, CdR] – Observatoire de Genève, Raoul Behrend
* {{NeoDys|101869}}
* {{ESA-SSA|101869|1999MM}}
* {{JPL small body}}

{{Small Solar System bodies}}

{{DEFAULTSORT:1999 MM}}
[[Category:Apollo asteroids|101869]]
[[Category:Potentially hazardous asteroids|101869]]

{{Sourceattribution|(101869) 1999 MM}}