View source for (35396) 1997 XF11

{{Short description|Asteroid of the Apollo group}}
{{DISPLAYTITLE:{{mp|(35396) 1997 XF|11}}}}
{{Use dmy dates|date=March 2020}}
{{Infobox planet
 | minorplanet     = yes
 | name            = {{mp|(35396) 1997 XF|11}}
 | background      = #FFC2E0
 | image           = 
 | caption         = 
 | discovery_ref   = <ref name="MPC-object" /><ref name="MPEC1997-Y11" />
 | discoverer      = [[Spacewatch]]
 | discovery_site  = [[Kitt Peak National Observatory|Kitt Peak National Obs.]]
 | discovered      = 6 December 1997
 | mpc_name        = {{mp|(35396) 1997 XF|11}}
 | alt_names       = {{mp|1997 XF|11}}
 | 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           = 13&nbsp;September 2023<br/>([[Julian day|JD]]&nbsp;2453300.5)
 | uncertainty     = 0
 | observation_arc = 33.19&nbsp;yr (12,121 days)
 | aphelion        = {{Convert|2.139|AU|e6km|abbr=unit|lk=on}}
 | perihelion      = {{Convert|0.7446|AU|e6km|abbr=unit}}
 | time_periastron = 26 June 2023
 | semimajor       = {{Convert|1.442|AU|e6km|abbr=unit}}
 | eccentricity    = 0.48369
 | period          = 1.73&nbsp;[[Julian year (astronomy)|yr]] (633 days)
 | inclination     = 4.0995°
 | asc_node        = 213.65°
 | arg_peri        = 103.06°
 | mean_anomaly    = 44.44[[Degree (angle)|°]]
 | mean_motion     = {{Deg2DMS|0.5688|sup=ms}} / day
 | moid            = {{Convert|0.0003|AU|e3km|abbr=unit}}
 | mean_diameter   = {{Ubl
  | {{val|0.704|0.103|u=km}}<ref name="Masiero-2017" />
  | {{val|0.940|0.480|u=km}}<ref name="Trilling-2016" />
  | 1.39&nbsp;km {{small|(derived)}}<ref name="lcdb" />
  }}
 | rotation        = {{Ubl
  | {{val|3.252|0.002|u=h}}<ref name="Martinez-2016" />
  | {{val|3.253|0.002|u=h}}<ref name="Warner-2016n" />
  | {{val|3.2566|0.0002|ul=h}}<ref name="Slivan-2003a" />
  | {{val|3.25765|0.00005|u=h}}<ref name="geneva-obs" />
  | 3.259&nbsp;h<ref name="lcdb" />
  | {{val|3.2591|0.0025|u=h}}<ref name="lcdb" />
  }}
 | albedo          = {{Ubl
  | 0.18 {{small|(assumed)}}<ref name="lcdb" />
  | {{val|0.29|0.21}}<ref name="Trilling-2016" />
  | {{val|0.7727|0.2436}}<ref name="Masiero-2017" />
  }}
 | spectral_type   = {{Hlist
  | [[SMASS classification|SMASS]] {{=}} Xk<ref name="jpldata" />
  | [[X-type asteroid|X]]<ref name="lcdb" />
  }}
 | abs_magnitude   = {{Ubl
  | 16.66<ref name="Masiero-2017" />
  | {{val|16.66|0.40}}<ref name="Veres-2015" />
  | 16.77<ref name="lcdb" />
  | {{val|16.77|0.08}}<ref name="lcdb" /><ref name="Pravec-2012b" />
  | 16.9<ref name="jpldata" />
  | {{val|17.11|0.22}}<ref name="Trilling-2016" />
  }}
}}

'''{{mp|(35396) 1997 XF|11}}''' ([[Minor planet provisional designation|provisional designation]] '''{{mp|1997 XF|11}}''') is a kilometer-sized [[asteroid]], classified as a [[near-Earth object]], [[Mars-crosser]] and [[potentially hazardous asteroid]] of the [[Apollo asteroid|Apollo group]].<ref name="MPC-object" />

{| class="wikitable" style="text-align:center; font-size: 0.9em;"
|+2028 Earth/Moon approach<ref name=jpldata/>
! Date & Time
! Approach<br />to
! [[Curve fitting|Nominal]] distance
! uncertainty<br />region<br />([[3-sigma]])
|-
|2028-Oct-26 06:44 || Earth || {{val|929253|u=km}}  || ± 106&nbsp;km<ref name="Horizons2028"/>
|-
|2028-Oct-26 07:39 || Moon || {{val|1326430|u=km}}  || ± 106&nbsp;km
|}

== Description ==

Three months after its discovery on 6 December 1997 by [[James V. Scotti]] of the [[University of Arizona]]'s [[Spacewatch Project]], the asteroid was predicted to make an exceptionally close approach to [[Earth]] on 28 October 2028. Additional [[precovery]] observations of the [[asteroid]] from 1990 were quickly found that refined the orbit and it is now known the asteroid will pass Earth on 26 October 2028, at a distance of {{convert|929000|km|LD|abbr=on|lk=on}}.<ref name=jpldata /><ref name=Sormano /><ref name=neodys /> During the close approach, the asteroid should peak at about [[apparent magnitude]] 8.2,<ref name="NEODyS2028" /> and will be visible in [[Binoculars#Astronomical|binoculars]].<ref name="nasa-news" />

{{mp|1997 XF|11}} measures between 0.7 and 1.4 kilometers in diameter.<ref name="lcdb" /><ref name="Masiero-2017" /><ref name="Trilling-2016" />

This asteroid also regularly comes near the large asteroid [[2 Pallas|Pallas]].<ref name=neodys />

=== IAU Circular ===

On 11 March 1998, using a three-month [[observation arc]], a faulty [[International Astronomical Union]] circular and press information sheet were put out that incorrectly concluded "that the asteroid was 'virtually certain' to pass within 80% of the distance to the Moon and stood a 'small...not entirely out of the question' possibility of hitting the Earth in 2028."<ref name="SwRI"/> But by 23 December 1997, it was clear that XF11 had no reasonable possibility of an Earth impact.<ref name="SwRI"/> Many news outlets mistakenly emphasized the possibility of disaster.<ref>{{Cite web |author=<!--Not stated--> |title=Twenty Years of Tracking Near-Earth Objects |url=https://www.jpl.nasa.gov/news/twenty-years-of-tracking-near-earth-objects |access-date=2024-07-23 |website=NASA Jet Propulsion Laboratory (JPL) |language=en-US}}</ref>

Within hours of the announcement, independent calculations by Paul Chodas, Don Yeomans, and Karri Muinonen had calculated that the probability of Earth impact was essentially zero, and vastly less than the probability of impact from as-yet-undiscovered asteroids.<ref name="SwRI" /> Chodas (1999) concurs with Marsden (1999) that based on the 1997 data alone there was about 1 chance in a hundred thousand that XF11 could have been on an Earth-impact trajectory—that is, until the 1990 precovery observations eliminated such possibilities.<ref name="ncar799" /> During the October 2002 close approach, the asteroid was observed by the 70-meter [[Goldstone Deep Space Communications Complex|Goldstone]] [[Radar astronomy|radar]] dish, further refining the orbit.<ref name="nasa-news" />

{{Large near earth asteroid flybys 5LD}}

==References==
{{reflist|refs=

<ref name="MPEC1997-Y11">{{Cite web
  |title=MPEC 1997-Y11 : 1997 XF11
  |publisher=[[IAU Minor Planet Center]]
  |date=1997-12-23
  |url=https://www.minorplanetcenter.net/iau/mpec/J97/J97Y11.html
  |accessdate=2012-02-08
  |archive-date=18 August 2017
  |archive-url=https://web.archive.org/web/20170818045155/http://www.minorplanetcenter.net/iau/mpec/J97/J97Y11.html
  |url-status=live
  }} (J97X11F)</ref>

<ref name="jpldata">{{cite web
 |type         = 2023-05-29 last obs.
 |title        = JPL Small-Body Database Browser: 35396 (1997 XF11)
 |url          = https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=2035396&view=OPC
 |publisher    = [[Jet Propulsion Laboratory]]
 |accessdate   = 2023-09-21
 |archive-date = 2 May 2021
 |archive-url  = https://web.archive.org/web/20210502171013/https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2000130#/?sstr=2035396&view=OPC
 |url-status   = live
}}</ref>

<ref name="Horizons2028">{{cite web
  |title=Horizons Batch for 2028-10-26 Close Approach
  |publisher=[[JPL Horizons On-Line Ephemeris System|JPL Horizons]]
  |url=https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%271997+XF11%27&START_TIME=%272028-10-26%2006:44%27&STOP_TIME=%272028-10-27%27&STEP_SIZE=%271%20day%27&QUANTITIES=%2720,39%27
  |archive-url=https://web.archive.org/web/20230112080448/https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%271997+XF11%27&START_TIME=%272028-10-26%2006:44%27&STOP_TIME=%272028-10-27%27&STEP_SIZE=%271%20day%27&QUANTITIES=%2720,39%27
  |archive-date=2023-01-12
  |url-status=live
  |accessdate=2023-01-12}} RNG_3sigma = uncertainty range in km.</ref>

<ref name="MPC-object">{{cite web
  |title      = 35396 (1997 XF11)
  |work      = [[Minor Planet Center]]
  |url      = https://www.minorplanetcenter.net/db_search/show_object?object_id=35396
  |accessdate      = 18 January 2018
  |archive-date      = 18 January 2018
  |archive-url      = https://web.archive.org/web/20180118064711/https://www.minorplanetcenter.net/db_search/show_object?object_id=35396
  |url-status      = live
  }}</ref>

<ref name=Sormano>{{cite web
 |title=Sormano Astronomical Observatory: Table of Next Closest Approaches to the Earth by Asteroids 
 |publisher=Astronomical Observatory of Brera 
 |author=Piero Sicoli 
 |author2=Francesco Manca 
 |url=http://www.brera.mi.astro.it/sormano/teca.html 
 |accessdate=2008-02-04 
 |archiveurl=https://web.archive.org/web/20071201202009/http://www.brera.mi.astro.it/sormano/teca.html 
 |archivedate=1 December 2007 
 |url-status=live 
 }}</ref>

<ref name=neodys>{{cite web
 |title       = NEODyS (35396) 1997XF11 Close Approaches
 |publisher   = Department of Mathematics, University of Pisa, ITALY
 |url         = https://newton.spacedys.com/neodys/index.php?pc=1.1.8&n=1997XF11
 |accessdate  = 2008-02-04
 |archiveurl  = https://web.archive.org/web/20160303182605/http://newton.dm.unipi.it/neodys/index.php?pc=1.1.8&n=1997xf11
 |archivedate = 2016-03-03
 |url-status  = live}}</ref>

<ref name="NEODyS2028">{{cite web
  |title=1997XF11 Ephemerides for 26 Oct 2028
  |publisher=NEODyS (Near Earth Objects{{Snd}} Dynamic Site)
  |url=https://newton.spacedys.com/neodys/index.php?pc=1.1.3.1&n=35396&oc=500&y0=2028&m0=10&d0=25&h0=0&mi0=0&y1=2028&m1=10&d1=28&h1=0&mi1=0&ti=1.0&tiu=hours
  |accessdate=2011-10-16
  |archive-date=21 April 2024
  |archive-url=https://web.archive.org/web/20240421003609/https://newton.spacedys.com/neodys/index.php?pc=1.1.3.1&n=35396&oc=500&y0=2028&m0=10&d0=25&h0=0&mi0=0&y1=2028&m1=10&d1=28&h1=0&mi1=0&ti=1.0&tiu=hours
  |url-status=live
  }}</ref>

<ref name="SwRI">{{cite web
  |date=5 April 1998
  |type=last update: 3 September 1998
  |title=The Asteroid Impact Scare of Mid-March 1998
  |publisher=Southwest Research Institute (SwRI)
  |author=Clark R. Chapman
  |url=http://www.boulder.swri.edu/clark/fx11.html
  |accessdate=2012-02-08
  |archive-date=24 November 2020
  |archive-url=https://web.archive.org/web/20201124042947/https://www.boulder.swri.edu/clark/fx11.html
  |url-status=live
  }}</ref>

<ref name="ncar799">{{cite web
  |date=19 August 1999
  |title=The AsteroidsComet Impact Hazard
  |publisher=Southwest Research Institute (SwRI)
  |author=Clark R. Chapman
  |url=http://www.boulder.swri.edu/clark/ncar799.html
  |accessdate=2012-02-09
  |archive-date=25 November 2020
  |archive-url=https://web.archive.org/web/20201125202042/https://www.boulder.swri.edu/clark/ncar799.html
  |url-status=live
  }}</ref>

<ref name="nasa-news">{{cite web
  |date=October 31, 2002
  |title=Halloween Asteroid
  |url=https://science.nasa.gov/science-news/science-at-nasa/2002/31oct_1997xf11/
  |accessdate=2012-02-09
  |archive-date=29 November 2011
  |archive-url=https://web.archive.org/web/20111129043456/http://science.nasa.gov/science-news/science-at-nasa/2002/31oct_1997xf11/
  |url-status=dead
  }}</ref>

<ref name="geneva-obs">{{cite web
 |title        = Asteroids and comets rotation curves{{Snd}} (35396)
 |last         = Behrend
 |first        = Raoul
 |publisher    = Geneva Observatory
 |url          = http://obswww.unige.ch/~behrend/page5cou.html#035396
 |accessdate   = 18 January 2018
 |archive-date = 19 June 2015
 |archive-url  = https://web.archive.org/web/20150619010828/http://obswww.unige.ch/%7Ebehrend/page5cou.html#035396
 |url-status   = live
}}</ref>

<ref name="lcdb">{{cite web 
  |title      = LCDB Data for (35396) 
  |publisher      = Asteroid Lightcurve Database (LCDB) 
  |url      = http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=35396%7C 
  |accessdate      = 18 January 2018 
  |archive-date      = 31 August 2020 
  |archive-url      = https://web.archive.org/web/20200831233109/http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=35396%7C 
  |url-status      = live 
  }}</ref>

<ref name="Trilling-2016">{{Cite journal
  |display-authors = 6
  |first1     = David E. |last1 = Trilling
  |first2     = Michael |last2 = Mommert
  |first3     = Joseph |last3 = Hora
  |first4     = Steve |last4 = Chesley
  |first5     = Joshua |last5 = Emery
  |first6     = Giovanni |last6 = Fazio
  |first7     = Alan |last7 = Harris
  |first8     = Michael |last8 = Mueller
  |first9     = Howard |last9 = Smith
  |date       = December 2016
  |title      = NEOSurvey 1: Initial Results from the Warm Spitzer Exploration Science Survey of Near-Earth Object Properties
  |journal    = The Astronomical Journal
  |volume     = 152
  |issue      = 6
  |page       = 10
  |bibcode    = 2016AJ....152..172T
  |doi        = 10.3847/0004-6256/152/6/172
  |arxiv= 1608.03673|s2cid = 56105212 |doi-access = free }}</ref>

<ref name="Masiero-2017">{{Cite journal
  |display-authors = 6
  |first1     = Joseph R. |last1 = Masiero
  |first2     = C. |last2 = Nugent
  |first3     = A. K. |last3 = Mainzer
  |first4     = E. L. |last4 = Wright
  |first5     = J. M. |last5 = Bauer
  |first6     = R. M. |last6 = Cutri
  |first7     = T. |last7 = Grav
  |first8     = E. |last8 = Kramer
  |first9     = S. |last9 = Sonnett
  |date       = October 2017
  |title      = NEOWISE Reactivation Mission Year Three: Asteroid Diameters and Albedos
  |journal    = The Astronomical Journal
  |volume     = 154
  |issue      = 4
  |page       = 10
  |bibcode    = 2017AJ....154..168M
  |doi        = 10.3847/1538-3881/aa89ec
  |arxiv      = 1708.09504
  |s2cid = 45334910 |doi-access = free }}</ref>

<ref name="Slivan-2003a">{{Cite journal
  |first1     = Stephen M. |last1 = Slivan
  |first2     = Emily C. |last2 = Bowsher
  |first3     = Bena W. |last3 = Chang
  |date       = December 2002
  |title      = Rotation period and spin direction of near-Earth asteroid (35396) 1997 XF11
  |journal    = The Minor Planet Bulletin
  |volume     = 30
  |issue      = 2
  |pages      = 29–30
  |issn       = 1052-8091
  |bibcode    = 2003MPBu...30...29S
  }}</ref>

<ref name="Warner-2016n">{{Cite journal
  |author     = Warner, Brian D.
  |date       = October 2016
  |title      = Near-Earth Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2016 April-July
  |journal    = The Minor Planet Bulletin
  |volume     = 43
  |issue      = 4
  |pages      = 311–319
  |issn       = 1052-8091
  |bibcode    = 2016MPBu...43..311W
  }}</ref>

<ref name="Martinez-2016">{{Cite journal
  |display-authors = 6
  |first1     = Vicente Mas |last1 = Martinez
  |first2     = Gonzalo Fornas |last2 = Silva
  |first3     = Angel Flores |last3 = Martinez
  |first4     = Alfonso Carreno |last4 = Garceran
  |first5     = Enrique Arce |last5 = Mansego
  |first6     = Pedro Brines |last6 = Rodriguez
  |first7     = Juan Lozano |last7 = de Haro
  |first8     = Alvaro Fornas |last8 = Silva
  |first9     = Onofre Rodrigo |last9 = Chiner
  |first10    = David Herrero |last10 = Porta
  |date       = October 2016
  |title      = Lightcurves for Two Near-Earth Asteroids by Asteroids Observers (OBAS) - MPPD: 2016 April-May
  |journal    = The Minor Planet Bulletin
  |volume     = 43
  |issue      = 4
  |pages      = 283–284
  |issn       = 1052-8091
  |bibcode    = 2016MPBu...43..283M
  }}</ref>

<ref name="Pravec-2012b">{{Cite journal
  |first1     = Petr |last1 = Pravec
  |first2     = Alan W. |last2 = Harris
  |first3     = Peter |last3 = Kusnirák
  |first4     = Adrián |last4 = Galád
  |first5     = Kamil |last5 = Hornoch
  |date       = September 2012
  |title      = Absolute magnitudes of asteroids and a revision of asteroid albedo estimates from WISE thermal observations
  |journal    = Icarus
  |volume     = 221
  |issue      = 1
  |pages      = 365–387
  |bibcode    = 2012Icar..221..365P
  |doi        = 10.1016/j.icarus.2012.07.026
  }}</ref>

<ref name="Veres-2015">{{cite journal
  |display-authors = 6
  |first1     = Peter |last1 = Veres
  |first2     = Robert |last2 = Jedicke
  |first3     = Alan |last3 = Fitzsimmons
  |first4     = Larry |last4 = Denneau
  |first5     = Mikael |last5 = Granvik
  |first6     = Bryce |last6 = Bolin
  |first7     = Serge |last7 = Chastel
  |first8     = Richard J. |last8 = Wainscoat
  |first9     = William S. |last9 = Burgett
  |first10    = Kenneth C. |last10 = Chambers
  |first11    = Heather |last11 = Flewelling
  |first12    = Nick |last12 = Kaiser
  |first13    = Eugen A. |last13 = Magnier
  |first14    = Jeff S. |last14 = Morgan
  |first15    = Paul A. |last15 = Price
  |first16    = John L. |last16 = Tonry
  |first17    = Christopher |last17 = Waters
  |date       = November 2015
  |title      = Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1{{Snd}} Preliminary results
  |journal    = Icarus
  |volume     = 261
  |pages      = 34–47
  |bibcode    = 2015Icar..261...34V
  |doi        = 10.1016/j.icarus.2015.08.007
  |arxiv      = 1506.00762
  |s2cid = 53493339 }}</ref>

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

== External links ==
* [https://web.archive.org/web/20061003012442/http://earn.dlr.de/nea/035396.htm {{mp|1997 XF|11}}] at the European Asteroid Research Node (E.A.R.N)
* [https://web.archive.org/web/20070927074124/http://www.britastro.com/jbaa/archive/marsden.htm Brian Marsden: {{mp|1997 XF|11}}: the true story] ([http://www.britastro.com/jbaa/archive/marsden.htm Archived from the original] {{Webarchive|url=https://web.archive.org/web/20070927074124/http://www.britastro.com/jbaa/archive/marsden.htm |date=27 September 2007 }})
* [https://web.archive.org/web/20071112233908/http://spacewatch.lpl.arizona.edu/1997XF11.html Spacewatch animation] of {{mp|1997 XF|11}}{{Dead link|date=July 2017}}
* [https://web.archive.org/web/20170216215019/http://neo.jpl.nasa.gov/news/1997xf11.html Asteroid {{mp|1997 XF|11}} (Earth Close-Approach)], JPL Near-Earth Object Program
* {{NeoDys|35396}}
* {{ESA-SSA|35396|1997XF11}}
* {{JPL small body}}

{{Minor planets navigator| |number=35396 |PageName={{mp|(35396) 1997 XF|11}} |}}
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{{DEFAULTSORT:1997 XF11}}
[[Category:Apollo asteroids|035396]]
[[Category:Discoveries by the Spacewatch project|035396]]
[[Category:Potentially hazardous asteroids|035396]]
[[Category:Xk-type asteroids (SMASS)|035396]]
[[Category:Astronomical objects discovered in 1997|19971206]]