View source for Astronomy:(523972) 1999 CW8

{{DISPLAYTITLE:{{mp|(523972) 1999 CW|8}}}}
{{Infobox planet
 | minorplanet     = yes
 | name            = {{mp|(523972) 1999 CW|8}}
 | background      = #FFC2E0
 | image           = Celestia 1999 CW8 orbit.png
 | image_scale      =
 | caption         = Orbital diagram of ''{{mp|1999 CW|8}}''
 | discovery_ref   = <ref name="MPC-object" />
 | discoverer      = LINEAR
 | discovery_site  = {{nowrap|Lincoln Laboratory ETS}}
 | discovered      = 12 February 1999
 | mpc_name        = {{mp|(523972) 1999 CW|8}}
 | alt_names       = {{mp|1999 CW|8}}
 | pronounced      = 
 | named_after     = 
 | mp_category     = [[Astronomy:Near-Earth object|NEO]]{{·}}[[Astronomy:Apollo asteroid|Apollo]]<ref name="MPC-object" /><ref name="jpldata" />
 | orbit_ref       = <ref name="jpldata" />
 | epoch           = 27 April 2019 ([[Astronomy:Julian day|JD]] 2458600.5)
 | uncertainty     = 0
 | observation_arc = 20.05 [[Astronomy:Julian year|yr]] (7,322 d)
 | aphelion        = 3.5757 [[Astronomy:Astronomical unit|AU]]
 | perihelion      = 0.8954 AU
 | semimajor       = 2.2355 AU
 | eccentricity    = 0.5995
 | period          = 3.34 yr (1,221 d)
 | mean_anomaly    = 353.67[[Degree (angle)|°]]
 | mean_motion     = {{Deg2DMS|0.2949|sup=ms}} / day
 | inclination     = 33.645°
 | asc_node        = 317.00°
 | arg_peri        = 262.11°
 | moid            = 0.23 AU (90.2 [[Astronomy:Lunar distance|LD]])
 | mars_moid       = 0.074 AU<ref name="MPC-object" />
 | satellites      =
 | mean_diameter   = {{val|0.64|ul=km}} {{small|(est at [[Physics:Geometric albedo|0.159]])}}<ref name="h" />
 | rotation        = 
 | albedo          = 
 | spectral_type   = SMASS {{=}} [[Astronomy:B-type asteroid|B]]<ref name="jpldata" />
 | abs_magnitude   = 18.6<ref name="MPC-object" /><ref name="jpldata" />
}}

'''{{mp|523972|1999 CW|8}}''', provisional designation {{mp|1999 CW|8}}, is a bright carbonaceous [[Astronomy:Asteroid|asteroid]] and sub-kilometer [[Astronomy:Near-Earth object|near-Earth object]] of the [[Astronomy:Apollo asteroid|Apollo group]], first observed on 12 February 1999, by astronomers of the Lincoln Near Earth Asteroid Research program at Lincoln Laboratory ETS in New Mexico, United States.<ref name="MPC-object" />

== Numbering and naming ==

This [[Astronomy:Minor planet|minor planet]] was numbered by the [[Organization:Minor Planet Center|Minor Planet Center]] on 18 May 2019 ({{small|M.P.C. 114615}}). As of 2019, it has not been named.<ref name="MPC-Circulars-Archive" />

== Orbit and classification ==
[[File:Celestia 1999 CW8 orbit edge on.png|200px|thumb|left|The orbit of {{mp|1999 CW|8}}, showing its inclination above the plane of the Solar System]]

{{mp|1999 CW|8}} is an [[Astronomy:Apollo asteroid|Apollo asteroid]] that crosses Earth's orbit. It orbits the Sun at a distance of 0.9–3.6&nbsp;[[Astronomy:Astronomical unit|AU]] once every 3 years and 4 months (1,221 days; semi-major axis of 2.24&nbsp;AU). Its orbit has an [[Astronomy:Orbital eccentricity|eccentricity]] of 0.60 and an [[Astronomy:Orbital inclination|inclination]] of 34[[Degree (angle)|°]] with respect to the [[Astronomy:Ecliptic|ecliptic]].<ref name="jpldata" /> The asteroid never approaches Earth closer than 0.2&nbsp;AU in the foreseeable future, but occasionally makes close approaches to [[Astronomy:Mars|Mars]] of 0.07&nbsp;AU. It makes one such approach in 2073, at 0.067&nbsp;AU, and another one in 2103, at 0.094 AU. Due to {{mp|1999 CW|8}}'s relatively high inclination, although it passes closer to the Sun than the Earth (0.9 AU), it never comes closer than 0.2&nbsp;AU.

== Physical characteristics ==

It is a carbonaceous [[Astronomy:B-type asteroid|B-type asteroid]], relatively rare in the asteroid belt but common in the inner Solar System.<ref name="jpldata" /> Based on an [[Astronomy:Absolute magnitude|absolute magnitude]] of 18.6,<ref name="MPC-object" /><ref name="jpldata" /> and an assumed [[Astronomy:Astronomical albedo|albedo]] of 0.159 (derived from the B-type asteroid [[Astronomy:2 Pallas|2 Pallas]]), the asteroid can be estimated to have a mean-diameter of approximately 640 meters.<ref name="h" /> If it impacted the Earth would cause significant damage, but not as much as the [[Earth:Cretaceous–Paleogene extinction event|Cretaceous–Paleogene extinction event]] progenitor, which brought about a mass extinction, as it is only 1/20 to 1/10 the size. However, it is unlikely to come close enough to Earth to impact it, or even become a risk of impact.

== See also ==
* Mars-crossing asteroid

== References ==
{{reflist|refs=

<ref name="jpldata">{{cite web
  |type       = 2019-03-01 last obs.
  |title      = JPL Small-Body Database Browser: (1999 CW8)
  |url        = https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=3019066
  |publisher  = [[Organization:Jet Propulsion Laboratory|Jet Propulsion Laboratory]]
  |accessdate = 29 May 2019}}</ref>

<ref name="MPC-object">{{cite web
  |title      = (523972) 1999 CW8
  |work       = Minor Planet Center
  |url        = https://www.minorplanetcenter.net/db_search/show_object?object_id=1999+CW8
  |accessdate = 29 May 2019}}</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 = 29 May 2019}}</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 = 16 October 2017}}</ref>

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

== External links ==
* {{NeoDys|1999+CW8}}
* {{ESA-SSA|523972|1999CW8}}
* {{JPL small body|id=3019066}}

{{Minor planets navigator | |number=523972 |PageName={{mp|(523972) 1999 CW|8}} | }}
{{Small Solar System bodies}}

{{DEFAULTSORT:1999 CW8}}
[[Category:Apollo asteroids|523972]]
[[Category:B-type asteroids (SMASS)|523972]]

{{Sourceattribution|(523972) 1999 CW8}}