[en]

(137108) 1999 AN₁₀
Discovery
Discovered by	LINEAR
Discovery date	13 January 1999
Designations
MPC designation	(137108) 1999 AN10
Minor planet category	NEO; Apollo; PHA;
Orbital characteristics
	Epoch 13 September 2023; (JD 2453300.5)
	Uncertainty parameter 0
Observation arc	66.97 yr
Earliest precovery date	26 January 1955
Aphelion	2.28 AU (341 million km)
Perihelion	0.638 AU (95.4 million km)
Semi-major axis	1.46 AU (218 million km)
Eccentricity	0.56224
Orbital period (sidereal)	1.76 yr (643.37 d)
Mean anomaly	313.20°
Mean motion	0° 33m 34.236s / day (n)
Inclination	39.929°
Longitude of ascending node	314.35°
Time of perihelion	5 December 2023
Argument of perihelion	268.33°
Earth MOID	0.00015 AU (22,000 km)
Physical characteristics
Dimensions	800–1800 m
Mass	~2.9×1012 kg
Equatorial escape velocity	~2.8 km/h
Sidereal rotation period	5.041 h
Absolute magnitude (H)	18.1

(137108) 1999 AN₁₀ is a kilometer-length near-Earth asteroid and potentially hazardous asteroid of the Apollo group. It was discovered by LINEAR on 13 January 1999.^[5]

On 7 August 2027, this asteroid will pass at about 0.00261 AU (390,000 km; 243,000 mi; 1.02 LD) of the Earth’s center.^[6]^[1]^[7]^[8] During the close approach, it is expected to peak at about apparent magnitude 7.3,^[9] and will be visible in binoculars.

1999 AN₁₀ has a well-determined orbit with an observation arc of 65 years.^[1] It was found by Andreas Doppler and Arno Gnädig in precovery images from 1955.^[1] When astronomers had an observation arc of the object of 123 days, computations gave a 1 in 10 million chance it would return on an impact trajectory in 2039.^[10]

On 7 August 1946, the asteroid passed 0.00625 AU (935,000 km; 581,000 mi) from Earth and then 0.00404 AU (604,000 km; 376,000 mi) from the Moon.^[1]

1999 AN10
Position uncertainty and increasing divergence^[1]
Date	JPL SBDB nominal geocentric distance (AU)	uncertainty region (3-sigma)
1946-08-07	0.006250 AU (935.0 thousand km)	±900 km
2027-08-07	0.002606 AU (389.9 thousand km)	±160 km
2076-02-04	0.027021 AU (4.0423 million km)	±154 thousand km
2198-02-01	0.063727 AU (9.5334 million km)	±800 thousand km

2027 Moon/Earth approach^[1]
Date & Time	Approach to	Nominal distance
2027-Aug-07 06:48	Moon	763391 km
2027-Aug-07 07:11	Earth	389866 km

PHA	Date	Approach distance (lunar dist.)			Abs. mag (H)	Diameter ^(C) (m)	Ref ^(D)
PHA	Date	Nomi- nal^(B)	Mini- mum	Maxi- mum	Abs. mag (H)	Diameter ^(C) (m)	Ref ^(D)
(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	15.3	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≈0.017 LD). ^(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

^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ “JPL Small-Body Database Browser: 137108 (1999 AN10)”. Retrieved 20 September 2023.
^ “137108 1999 AN10”. The Near-Earth Asteroids Data Base at E.A.R.N. Archived from the original on 24 February 2012. Retrieved 31 January 2008.
^ “Asteroid Size Estimator”. CNEOS NASA/JPL. Retrieved 20 April 2018.
^ ^a ^b assume radius of 0.650 km; volume of a sphere * assume density of 2.6g/cm³ (though it could be a loose rubble pile) yields a mass of 2.99×10¹² kg and an escape velocity of 2.82 km/h.
^ Hannu, Karttunen; Vilppu, Piirola (1999). Astrophysics with the NOT: Proceedings of the conference held in Turku on August 12–15, 1998. University of Turku. p. 270. ISBN 951-29-1615-0.
^ 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 31 January 2008.
^ “NEODys (137108) 1999AN10”. Department of Mathematics, University of Pisa, ITALY. Archived from the original on 6 December 2014. Retrieved 31 January 2008.
^ “MPEC 1999-N21: 1999 AN10”. IAU: Minor Planet Center. 12 July 1999. Retrieved 31 January 2008.
^ “1999AN10 Ephemerides for 7 Aug 2027”. NEODyS (Near Earth Objects – Dynamic Site). Retrieved 16 October 2011.
^ Paul W. Chodas (18 May 1999). “The Continuing Story Of Asteroid 1999 AN10”. Archived from the original on 26 October 2010. Retrieved 22 October 2010.