Editing (89959) 2002 NT7

{{Short description|Asteroid}}
{{DISPLAYTITLE:{{mp|(89959) 2002 NT|7}}}}
{{Use mdy dates|date=March 2020}}
{{Infobox planet
 | minorplanet     = yes
 | name            = (89959) {{mp|2002 NT|7}}
 | background      = #FFC2E0
 | image           = 
 | caption         = 
 | discovery_ref   = <ref name="MPEC2002-N38"/>
 | discovered      = 9 July 2002
 | discoverer      = [[Lincoln Near-Earth Asteroid Research|LINEAR]]
 | discovery_site  = [[Lincoln Laboratory's Experimental Test Site|Lincoln Lab's ETS]]
 | mpc_name        = (89959) {{mp|2002 NT|7}}
 | alt_names       = {{mp|2002 NT|7}}
 | pronounced      = 
 | named_after     =
 | mp_category     = {{Hlist
  | [[Apollo asteroid|Apollo]]
  | [[Near-Earth object|NEO]]
  | [[Potentially hazardous object|PHA]]<ref name="jpldata" /><ref name="MPC-object" />
  }}
 | orbit_ref       = <ref name="jpldata" />
 | epoch           = 23 March 2018 ([[Julian day|JD]]&nbsp;2457800.5)
 | uncertainty     = 0
 | observation_arc = 62.68&nbsp;yr (22,894 days)
 | aphelion        = 2.6529&nbsp;[[Astronomical unit|AU]]
 | perihelion      = 0.8180&nbsp;AU
 | semimajor       = 1.7355&nbsp;AU
 | eccentricity    = 0.5286
 | period          = 2.29&nbsp;[[Julian year (astronomy)|yr]] (835 days)
 | mean_anomaly    = 79.375[[Degree (angle)|°]]
 | mean_motion     = {{Deg2DMS|0.4311|sup=ms}} / day
 | inclination     = 42.333°
 | asc_node        = 132.08°
 | arg_peri        = 300.67°
 | moid            = {{convert|0.0004|AU|km mi|abbr=on|lk=off}}
 | mean_diameter   = {{val|1.407|0.085|u=km}}<ref name="Mainzer-2011" />
 | rotation        = 
 | albedo          = {{val|0.224|0.053}}<ref name="Mainzer-2011" />
 | spectral_type   = 
 | abs_magnitude   = 16.4<ref name="jpldata" />
}}

'''{{mp|(89959) 2002 NT|7}}'''  ([[Minor planet provisional designation|provisional designation]] '''{{mp|2002 NT|7}}''') is a [[near-Earth object]] with a diameter of 1.4 kilometers and [[potentially hazardous asteroid]] of the [[Apollo asteroid|Apollo group]].<ref name="jpldata" /><ref name="MPC-object" /> It has a well determined orbit with an [[observation arc]] of 64 years including [[precovery]] images by [[Palomar Observatory]] dating back to 1954.<ref name="MPC-object"/>

{{mp|2002 NT|7}} became the first object observed by [[NASA]]'s NEO program to be assigned a positive rating on both the [[Torino scale]] and the [[Palermo scale]]<ref name="hohmanntransfer"/> for a small chance of an impact on 1 February 2019, however it passed Earth at roughly {{convert|0.4078|AU|km mi|abbr=on|lk=on}} on 13 January 2019 with an uncertainty region of around ±108&nbsp;km.<ref name=jpl-close/>

== Discovery ==
It was discovered on 9 July 2002 by the [[Lincoln Near-Earth Asteroid Research]] team (LINEAR) at the U.S. [[Lincoln Laboratory Experimental Test Site]] near Socorro, New Mexico.<ref name="MPEC2002-N38" /> At the time of discovery it only had a 6-day observation arc of 9–14 July,<ref name="MPEC2002-N38" /> which poorly constrained possible future positions of the asteroid.

Despite inflammatory press reports, the object had a "low probability" of impact, approximately one in a million, for 1 February 2019.<ref name=planetary/> On 22 July 2002, [[NEODyS]] posted a positive 0.18 Palermo scale rating.<ref name="hohmanntransfer"/> Further observations, especially from [[Erich Meyer]], quickly lowered the probability. [https://skyandtelescope.org/astronomy-news/astro-news-briefs-july-2228/]. On 25 July 2002, the hazard rating on the Palermo scale was lowered to −0.25. However, the discovery of the object with an initial Palermo scale rating of 0.06<ref name= "BBC-NT7"/> was a historical event for the NEO observation program.

{{mp|2002 NT|7}} was removed from the [[Sentry (monitoring system)|Sentry Risk Table]] on 1 August 2002 (23 days after discovery), meaning there is no risk of an impact by it in the next 100 years.<ref name="removed"/> On 13 January 2019, the asteroid safely passed {{convert|0.4078|AU|km mi|abbr=on|lk=on}} from Earth with a [[3-sigma]] uncertainty region of about ±108&nbsp;km.<ref name=jpl-close/> Between 1900 and 2195 the closest approach to Earth will occur on 15 January 2099 at a distance of roughly {{convert|0.3739|AU|km mi|abbr=on|lk=off}} with an uncertainty region of about ±430&nbsp;km.<ref name=jpl-close/>

On 30 January 2020, the asteroid safely passed {{convert|0.02718|AU|km mi|abbr=on|lk=off}} from [[2 Pallas]].<ref name="NEODyS"/>

== References ==
{{reflist
| refs =

<ref name="MPEC2002-N38">{{cite web
  |title=MPEC 2002-N38 : 2002 NT7
  |publisher=[[IAU Minor Planet Center]]
  |date=2002-07-14
  |url=https://minorplanetcenter.net//iau/mpec/K02/K02N38.html }} (K02N07T)</ref>

<ref name="jpldata">{{cite web
  |type       = 2017-03-15 last obs.
  |title      = JPL Small-Body Database Browser: 89959 (2002 NT7)
  |url        = https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2089959
  |publisher  = [[Jet Propulsion Laboratory]]
  |access-date = 26 April 2017}}</ref>

<ref name="MPC-object">{{cite web
  |title      = 89959 (2002 NT7)
  |work       = Minor Planet Center
  |url        = https://www.minorplanetcenter.net/db_search/show_object?object_id=89959
  |access-date = 26 April 2017}}</ref>

<ref name="Mainzer-2011">{{Cite journal
  |display-authors = 6
  |first1     = A. |last1 = Mainzer
  |first2     = T. |last2 = Grav
  |first3     = J. |last3 = Bauer
  |first4     = J. |last4 = Masiero
  |first5     = R. S. |last5 = McMillan
  |first6     = R. M. |last6 = Cutri
  |first7     = R. |last7 = Walker
  |first8     = E. |last8 = Wright
  |first9     = P. |last9 = Eisenhardt
  |first10    = D. J. |last10 = Tholen
  |first11    = T. |last11 = Spahr
  |first12    = R. |last12 = Jedicke
  |first13    = L. |last13 = Denneau
  |first14    = E. |last14 = DeBaun
  |first15    = D. |last15 = Elsbury
  |first16    = T. |last16 = Gautier
  |first17    = S. |last17 = Gomillion
  |first18    = E. |last18 = Hand
  |first19    = W. |last19 = Mo
  |first20    = J. |last20 = Watkins
  |first21    = A. |last21 = Wilkins
  |first22    = G. L. |last22 = Bryngelson
  |first23    = A. |last23 = Del Pino Molina
  |first24    = S. |last24 = Desai
  |first25    = M. |last25 = Gómez Camus
  |first26    = S. L. |last26 = Hidalgo
  |first27    = I. |last27 = Konstantopoulos
  |first28    = J. A. |last28 = Larsen
  |first29    = C. |last29 = Maleszewski
  |first30    = M. A. |last30 = Malkan
  |first31    = J.-C. |last31 = Mauduit
  |first32    = B. L. |last32 = Mullan
  |first33    = E. W. |last33 = Olszewski
  |first34    = J. |last34 = Pforr
  |first35    = A. |last35 = Saro
  |first36    = J. V. |last36 = Scotti
  |first37    = L. H. |last37 = Wasserman
  |date       = December 2011
  |title      = NEOWISE Observations of Near-Earth Objects: Preliminary Results
  |url        = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2011ApJ...743..156M
  |journal    = The Astrophysical Journal
  |volume     = 743
  |issue      = 2
  |page       = 17
  |bibcode    = 2011ApJ...743..156M
  |doi        = 10.1088/0004-637X/743/2/156
  |arxiv      = 1109.6400
  |s2cid = 239991 |access-date = 26 April 2017}}</ref>

<ref name=planetary>[http://www.planetary.org/news/2002/0725_Asteroid_2002_NT7_Under_Watch_But.html Asteroid 2002 NT7 Under Watch, But Probably Not Coming Our Way] {{webarchive|url=https://web.archive.org/web/20060405010848/http://www.planetary.org/news/2002/0725_Asteroid_2002_NT7_Under_Watch_But.html |date=2006-04-05 }} (25 July 2002)</ref>

<ref name="hohmanntransfer">{{cite web
  |date=29 March 2003
  |title=How A/CC broke the 2002 NT7 story
  |publisher=hohmanntransfer
  |url=http://www.hohmanntransfer.com/sas/nt7/index.html
  |archive-url=https://web.archive.org/web/20201106104922/http://www.hohmanntransfer.com/sas/nt7/index.html
  |archive-date=2020-11-06 |url-status=dead
  |access-date=2019-04-25}}</ref>

<ref name="removed">{{cite web
  |title=Date/Time Removed
  |publisher=NASA/JPL Near-Earth Object Program Office
  |url=http://neo.jpl.nasa.gov/risk/removed.html
  |archive-url=https://web.archive.org/web/20020602101400/http://neo.jpl.nasa.gov/risk/removed.html
  |url-status=dead
  |archive-date=2002-06-02
  |access-date=2011-05-06}}</ref>

<ref name="BBC-NT7">{{cite news
  |date=24 July 2002
  |title=Space rock 'on collision course'
  |work=[[BBC News]]
  |url=http://news.bbc.co.uk/2/hi/science/nature/2147879.stm
  |access-date=2007-12-28}}</ref>

<ref name=jpl-close>{{cite web
  |type=last observation: 2011-09-12; [[Observation arc|arc]]: 57 years
  |title=JPL Close-Approach Data: 89959 (2002 NT7)
  |url=https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2002NT7;cad=1#cad
  |access-date=2011-11-04}}</ref>

<ref name="NEODyS">{{cite web
  |title=NEODyS-2 Close Approaches for (89959) 2002NT7
  |publisher=Near Earth Objects{{Snd}} Dynamic Site
  |url=https://newton.spacedys.com/neodys/index.php?pc=1.1.8&n=2002NT7
  |access-date=2011-11-05}}</ref>

}} <!-- end of notelist -->

== External links ==
* [https://twitter.com/ptastro1/status/1002854106300469248 Simulation of the shrinking uncertainty region for 2019 Jan 28]{{Snd}} Peter Thomas
* {{NeoDys|89958}}
* {{ESA-SSA|89958|2002NT7}}
* {{JPL small body|id=89959}}

{{Minor planets navigator |(89958) 2002 LY45 |number=89959 |PageName={{mp|(89959) 2002 NT|7}} | }}
{{Small Solar System bodies}}
{{Authority control}}

{{DEFAULTSORT:2002 NT7}}
[[Category:Apollo asteroids|089959]]
[[Category:Discoveries by LINEAR|089959]]
[[Category:Near-Earth objects removed from the Sentry Risk Table|089959]]
[[Category:Potentially hazardous asteroids|089959]]
[[Category:Near-Earth objects in 2019|20190113]]
[[Category:Astronomical objects discovered in 2002|20020709]]