1509 Esclangona

1509 Esclangona, provisional designation 1938 YG, is a rare-type Hungaria asteroid and binary system from the inner regions of the asteroid belt, approximately 8 kilometers in diameter. It is named after French astronomer Ernest Esclangon.

1509 Esclangona

Discovery[1]
Discovered by	A. Patry
Discovery site	Nice Obs.
Discovery date	21 December 1938
Designations
MPC designation	(1509) Esclangona
Named after	Ernest Esclangon (French astronomer)[2]
Alternative designations	1938 YG
Minor planet category	main-belt · (inner)[1] Hungaria[3][4][5]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc	77.68 yr (28,374 days)
Aphelion	1.9263 AU
Perihelion	1.8064 AU
Semi-major axis	1.8663 AU
Eccentricity	0.0321
Orbital period (sidereal)	2.55 yr (931 days)
Mean anomaly	225.08°
Mean motion	0° 23m 11.76s / day
Inclination	22.320°
Longitude of ascending node	283.52°
Argument of perihelion	267.82°
Known satellites	1[6]
Physical characteristics
Dimensions	6.83±1.32 km[7] 7.52±1.78 km[8] 8.17±0.6 km (IRAS:2)[9] 8.18 km (derived)[4] 9.0±1.0 km[10] 9.87±0.37 km[11]
Synodic rotation period	2.64±0.02 h[12] 3.247 h[10] 3.247±0.002 h[13] 3.252±0.005 h[14][a] 3.2524±0.0003 h[15] 3.25250±0.00005 h[16] 3.25281±0.00002 h[b] 3.25283±0.00002 h[17] 5.89 h[c]
Geometric albedo	0.107±0.021[10] 0.160±0.013[11] 0.185±0.055[18] 0.2041 (derived)[4] 0.2327±0.038 (IRAS:2)[9] 0.30±0.14[8] 0.41±0.18[7]
Spectral type	Tholen = S[1] · K[19] · S[4] B–V = 0.894[1] U–B = 0.472[1]
Absolute magnitude (H)	12.33±0.14 (R)[b] · 12.64[1][7][9][11] · 12.79[8] · 12.858±0.149[4][20] · 13.28±0.0[10]

Discoveries

Esclangona was discovered on 21 December 1938, by French astronomer André Patry at Nice Observatory. The body's observation arc begins with its official discovery observation as no precoveries were taken, and no prior identifications were made.^[3] On 13 February 2003, a minor-planet moon in orbit of Esclangona was discovered by astronomers at ESO's Very Large Telescope (UT4) on Cerro Paranal in Chile.^[2][3]

Orbit and classification

Esclangona is a member of the Hungaria family, which form the innermost concentration of asteroids in the Solar System. It orbits the Sun in the inner main-belt at a distance of 1.8–1.9 AU once every 2 years and 7 months (931 days). Its orbit has an eccentricity of 0.03 and an inclination of 22° with respect to the ecliptic.^[1]

Binary system

Esclangona has a small moon, provisionally named S/2003 (1509) 1, which measures 4 kilometers in diameter, and orbits 140 kilometers from its parent. This wide separation relative to the pair's size is rather unusual and it is believed that both Esclangona and its moon are ejecta from an asteroidal collision in the past that left the scene as a co-orbiting pair; a similar pairing is 3749 Balam and its outer moon.^[6]

Physical characteristics

In the Tholen taxonomy, Esclangona is a common stony S-type asteroid. It has since been characterized as a rare K-type asteroid by polarimetric observations.^[19]

Rotation period

In December 2004, photometric measurements of Esclangona made by American astronomer Brian Warner at his Palmer Divide Observatory, California, showed a lightcurve with a rotation period of 3.247±0.002 hours and a brightness variation of 0.17±0.02 in magnitude.^[13][a]

Diameter and albedo

According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite, and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Esclangona measures between 6.83 and 9.87 kilometers in diameter and its surface has an albedo between 0.107 and 0.41.^{[7][8][9][11]} The Collaborative Asteroid Lightcurve Link derives an albedo of 0.2041 and a diameter of 8.18 kilometers with an absolute magnitude of 12.858.^[4]

Naming

This minor planet was named after French astronomer Ernest Esclangon (1876–1954), was a director of the Paris Observatory and president of the International Astronomical Union. Naming citation was first mentioned in The Names of the Minor Planets by Paul Herget in 1955 (H 134).^[2]

Notes

1. Lightcurve plot of 1509 Esclangona Palmer Divide Observatory, B. D. Warner (2013)
2. Pravec (2009) web: Date: 2009-10-06. Rotation period 3.25281±0.00002 hours with a brightness amplitude of 0.13 mag. Flagged as binary. Quality code: n.a. Summary figures at Collaborative Asteroid Lightcurve Link (CALL) for (1509) Esclangona
3. CALL (2011) web: rotation period 5.89 hours with a brightness amplitude of 0.35 mag. Quality code: n.a. Summary figures at Collaborative Asteroid Lightcurve Link (CALL) for (1509) Esclangona