(35396) 1997 XF₁₁

(35396) 1997 XF₁₁, provisional designation 1997 XF₁₁, is a kilometer-sized asteroid, classified as near-Earth object, Mars-crosser and potentially hazardous asteroid of the Apollo group.[1]

(35396) 1997 XF₁₁

Discovery [1][2]
Discovered by	Spacewatch
Discovery site	Kitt Peak National Obs.
Discovery date	6 December 1997
Designations
MPC designation	(35396) 1997 XF11
Alternative designations	1997 XF11
Minor planet category	Apollo NEO PHA [3][1]
Orbital characteristics [3]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc	26.84 yr (9,802 days)
Aphelion	2.1409 AU
Perihelion	0.7446 AU
Semi-major axis	1.4427 AU
Eccentricity	0.4839
Orbital period	1.73 yr (633 days)
Mean anomaly	233.07°
Mean motion	0° 34^m 7.68^s / day
Inclination	4.0985°
Longitude of ascending node	213.76°
Argument of perihelion	102.92°
Earth MOID	0.0006 AU (0.2 LD)
Physical characteristics
Mean diameter	0.704±0.103 km[4] 0.940±0.480 km[5] 1.39 km (derived)[6]
Rotation period	3.252±0.002 h[7] 3.253±0.002 h[8] 3.2566±0.0002 h[9] 3.25765±0.00005 h[10] 3.259 h[6] 3.2591±0.0025 h[6]
Geometric albedo	0.18 (assumed)[6] 0.29±0.21[5] 0.7727±0.2436[4]
Spectral type	SMASS = Xk [3] X [6]
Absolute magnitude (H)	16.66[4] 16.66±0.40[11] 16.77[6] 16.77±0.08[6][12] 16.9[3] 17.11±0.22[5]

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 the Earth on 26 October 2028, at a distance of 0.0062 AU (930,000 km; 580,000 mi), about 2.4 times the Earth–Moon distance.[13][14][15] During the close approach, the asteroid should peak at about apparent magnitude 8.2,[16] and will be visible in binoculars.[17]

1997 XF₁₁ measures between 0.7 and 1.4 kilometers in diameter.[6][4][5]

This asteroid also regularly comes near the large asteroid Pallas.[14]

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."[18] But by 23 December 1997, it should have been clear that XF11 had no reasonable possibility of an Earth impact.[18] 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.[18] Chodas (1999) concurs with Marsden (1999) that there was about 1 chance in a hundred thousand that XF11 could have passed through a keyhole—that is, until the 1990 precovery observations eliminated such possibilities.[19] During the October 2002 close approach, the asteroid was observed by the 70-meter Goldstone radar dish, further refining the orbit.[17]

History of close approaches of large near-Earth objects since 1908 ^(A)

PHA	Date	Approach distance (lunar dist.)			Abs. mag (H)	Diameter ^(C) (m)	Ref ^(D)
		Nomi- nal^(B)	Mini- mum	Maxi- mum
(33342) 1998 WT24	1908-12-16	3.542	3.537	3.547	17.9	556–1795	data
(458732) 2011 MD5	1918-09-17	0.911	0.909	0.913	17.9	556–1795	data
(7482) 1994 PC1	1933-01-17	2.927	2.927	2.928	16.8	749–1357	data
69230 Hermes	1937-10-30	1.926	1.926	1.927	17.5	668–2158	data
69230 Hermes	1942-04-26	1.651	1.651	1.651	17.5	668–2158	data
(137108) 1999 AN10	1946-08-07	2.432	2.429	2.435	17.9	556–1795	data
(33342) 1998 WT24	1956-12-16	3.523	3.523	3.523	17.9	556–1795	data
(163243) 2002 FB3	1961-04-12	4.903	4.900	4.906	16.4	1669–1695	data
(192642) 1999 RD32	1969-08-27	3.627	3.625	3.630	16.3	1161–3750	data
(143651) 2003 QO104	1981-05-18	2.761	2.760	2.761	16.0	1333–4306	data
2017 CH1	1992-06-05	4.691	3.391	6.037	17.9	556–1795	data
(170086) 2002 XR14	1995-06-24	4.259	4.259	4.260	18.0	531–1714	data
(33342) 1998 WT24	2001-12-16	4.859	4.859	4.859	17.9	556–1795	data
4179 Toutatis	2004-09-29	4.031	4.031	4.031	15.30	2440–2450	data
2014 JO25	2017-04-19	4.573	4.573	4.573	17.8	582–1879	data
(137108) 1999 AN10	2027-08-07	1.014	1.010	1.019	17.9	556–1795	data
(35396) 1997 XF11	2028-10-26	2.417	2.417	2.418	16.9	881–2845	data
(154276) 2002 SY50	2071-10-30	3.415	3.412	3.418	17.6	714–1406	data
(164121) 2003 YT1	2073-04-29	4.409	4.409	4.409	16.2	1167–2267	data
(385343) 2002 LV	2076-08-04	4.184	4.183	4.185	16.6	1011–3266	data
(52768) 1998 OR2	2079-04-16	4.611	4.611	4.612	15.8	1462–4721	data
(33342) 1998 WT24	2099-12-18	4.919	4.919	4.919	17.9	556–1795	data
(85182) 1991 AQ	2130-01-27	4.140	4.139	4.141	17.1	1100	data
314082 Dryope	2186-07-16	3.709	2.996	4.786	17.5	668–2158	data
(137126) 1999 CF9	2192-08-21	4.970	4.967	4.973	18.0	531–1714	data
(290772) 2005 VC	2198-05-05	1.951	1.791	2.134	17.6	638–2061	data
^(A) List includes near-Earth approaches of less than 5 lunar distances (LD) of objects with H brighter than 18. ^(B) Nominal geocentric distance from the Earth's center to the object's center (earth radius≈6400 km). ^(C) Diameter: estimated, theoretical mean-diameter based on H and albedo range between X and Y. ^(D) Reference: data source from the JPL SBDB, with AU converted into LD (1 AU≈390 LD) ^(E) Color codes:   unobserved at close approach   observed during close approach   upcoming approaches

References

1. "35396 (1997 XF11)". Minor Planet Center. Retrieved 18 January 2018.
2. "MPEC 1997-Y11 : 1997 XF11". IAU Minor Planet Center. 23 December 1997. Retrieved 8 February 2012. (J97X11F)
3. "JPL Small-Body Database Browser: 35396 (1997 XF11)" (2017-01-21 last obs.). Jet Propulsion Laboratory. Retrieved 18 January 2018.
4. Masiero, Joseph R.; Nugent, C.; Mainzer, A. K.; Wright, E. L.; Bauer, J. M.; Cutri, R. M.; et al. (October 2017). "NEOWISE Reactivation Mission Year Three: Asteroid Diameters and Albedos". The Astronomical Journal. 154 (4): 10. arXiv:1708.09504. Bibcode:2017AJ....154..168M. doi:10.3847/1538-3881/aa89ec.
5. Trilling, David E.; Mommert, Michael; Hora, Joseph; Chesley, Steve; Emery, Joshua; Fazio, Giovanni; et al. (December 2016). "NEOSurvey 1: Initial Results from the Warm Spitzer Exploration Science Survey of Near-Earth Object Properties". The Astronomical Journal. 152 (6): 10. arXiv:1608.03673. Bibcode:2016AJ....152..172T. doi:10.3847/0004-6256/152/6/172.
6. "LCDB Data for (35396)". Asteroid Lightcurve Database (LCDB). Retrieved 18 January 2018.
7. Martinez, Vicente Mas; Silva, Gonzalo Fornas; Martinez, Angel Flores; Garceran, Alfonso Carreno; Mansego, Enrique Arce; Rodriguez, Pedro Brines; et al. (October 2016). "Lightcurves for Two Near-Earth Asteroids by Asteroids Observers (OBAS) - MPPD: 2016 April-May". The Minor Planet Bulletin. 43 (4): 283–284. Bibcode:2016MPBu...43..283M. ISSN 1052-8091.
8. Warner, Brian D. (October 2016). "Near-Earth Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2016 April-July". The Minor Planet Bulletin. 43 (4): 311–319. Bibcode:2016MPBu...43..311W. ISSN 1052-8091.
9. Slivan, Stephen M.; Bowsher, Emily C.; Chang, Bena W. (December 2002). "Rotation period and spin direction of near-Earth asteroid (35396) 1997 XF11". The Minor Planet Bulletin. 30 (2): 29–30. Bibcode:2003MPBu...30...29S. ISSN 1052-8091.
10. Behrend, Raoul. "Asteroids and comets rotation curves – (35396)". Geneva Observatory. Retrieved 18 January 2018.
11. Veres, Peter; Jedicke, Robert; Fitzsimmons, Alan; Denneau, Larry; Granvik, Mikael; Bolin, Bryce; et al. (November 2015). "Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 – Preliminary results". Icarus. 261: 34–47. arXiv:1506.00762. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007.
12. Pravec, Petr; Harris, Alan W.; Kusnirák, Peter; Galád, Adrián; Hornoch, Kamil (September 2012). "Absolute magnitudes of asteroids and a revision of asteroid albedo estimates from WISE thermal observations". Icarus. 221 (1): 365–387. Bibcode:2012Icar..221..365P. doi:10.1016/j.icarus.2012.07.026.
13. Piero Sicoli; Francesco Manca. "Sormano Astronomical Observatory: Table of Next Closest Approaches to the Earth by Asteroids". Astronomical Observatory of Brera. Archived from the original on 1 December 2007. Retrieved 4 February 2008.
14. "NEODyS (35396) 1997XF11 Close Approaches". Department of Mathematics, University of Pisa, ITALY. Archived from the original on 3 March 2016. Retrieved 4 February 2008.
15. "JPL Close-Approach Data: 35396 (1997 XF11)" (last observation: 2012-02-02; arc: 21.87 years). Retrieved 8 February 2012.
16. "1997XF11 Ephemerides for 26 Oct 2028". NEODyS (Near Earth Objects – Dynamic Site). Retrieved 16 October 2011.
17. "Halloween Asteroid". Science@NASA. 31 October 2002. Retrieved 9 February 2012.
18. Clark R. Chapman (5 April 1998). "The Asteroid Impact Scare of Mid-March 1998" (last update: 3 September 1998). Southwest Research Institute (SwRI). Retrieved 8 February 2012.
19. Clark R. Chapman (19 August 1999). "The AsteroidsComet Impact Hazard". Southwest Research Institute (SwRI). Retrieved 9 February 2012.

External links

• 1997 XF₁₁ at the European Asteroid Research Node (E.A.R.N)
• Brian Marsden: 1997 XF₁₁: the true story (Archived from the original)
• Spacewatch animation of 1997 XF₁₁dead link]
• Asteroid 1997 XF₁₁ (Earth Close-Approach), JPL Near-Earth Object Program
• (35396) 1997 XF11 at NeoDyS-2, Near Earth Objects—Dynamic Site
  • Ephemeris · Obs prediction · Orbital info · MOID · Proper elements · Obs info · Close · Physical info · NEOCC
• (35396) 1997 XF11 at ESA–space situational awareness
  • Ephemerides · Observations · Orbit · Physical Properties · Summary
• (35396) 1997 XF11 at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit diagram · Orbital elements · Physical parameters