230 Athamantis

230 Athamantis
	VLT-SPHERE image of Athamantis
Discovery
Discovered by	K. de Ball
Discovery date	3 September 1882
Designations
Pronunciation	/æθəˈmæntɪs/
Named after	Helle
Alternative designations	1949 WG
Minor planet category	Main belt
Orbital characteristics
	Epoch 31 July 2016 (JD 2457600.5)
	Uncertainty parameter 0
Observation arc	133.58 yr (48791 d)
Aphelion	2.52818 AU (378.210 Gm)
Perihelion	2.23641 AU (334.562 Gm)
Semi-major axis	2.38229 AU (356.386 Gm)
Eccentricity	0.06124
Orbital period (sidereal)	3.68 yr (1343.0 d)
Average orbital speed	19.3 km/s
Mean anomaly	116.2°
Mean motion	0° 16m 4.969s / day
Inclination	9.443°
Longitude of ascending node	239.9°
Argument of perihelion	139.1°
Physical characteristics
Mean diameter	118±2 km; 111.332±1.231 km; 110.17 ± 4.57 km (composite estimate)
Flattening	0.24
Mass	(1.98±0.16)×1018 kg
Mean density	2.31±0.22 g/cm3
Synodic rotation period	24.0055 h (1.00023 d); 23.99 h
Geometric albedo	0.146 (calculated); 0.164±0.029
Spectral type	S
Absolute magnitude (H)	7.53

230 Athamantis is a fairly large main-belt asteroid that was discovered by the German-Austrian astronomer K. de Ball on September 3, 1882, in Bothkamp. It was his only asteroid discovery. The asteroid was named after Athamantis, daughter of Athamas the mythical Greek king of Orchomenus.

Photometric observations of this asteroid gave a light curve with a period of 23.99 hours and a brightness variation of more than 0.20 in magnitude. It has the spectrum of an S-type asteroid. During 1991, the asteroid was observed occulting a star. The resulting chords provided a cross-section diameter estimate of 101.8 km.

Notes

↑ Flattening derived from the maximum aspect ratio (c/a): $f=1-{\frac {c}{a}}$ , where (c/a) = 0.76±0.07.
↑ Calculated from its standard gravitational parameter GM = 0.132±0.011 km³/s².
↑ Assuming a diameter of 118 ± 2 km.

References

1 2 3 4 5 "230 Athamantis". JPL Small-Body Database. NASA/Jet Propulsion Laboratory. Retrieved 12 May 2016.
1 2 3 P. Vernazza et al. (2021) VLT/SPHERE imaging survey of the largest main-belt asteroids: Final results and synthesis. Astronomy & Astrophysics 54, A56
↑ Carry, B. (December 2012), "Density of asteroids", Planetary and Space Science, vol. 73, pp. 98–118, arXiv:1203.4336, Bibcode:2012P&SS...73...98C, doi:10.1016/j.pss.2012.03.009. See Table 1.
1 2 Fuentes-Muñoz, Oscar; Farnocchia, Davide; Giorgini, Jon D.; Park, Ryan S. (1 December 2025). "Asteroid Mass Estimation by Mutual Perturbations During Close Encounters After Gaia Focused Product Release". The Astronomical Journal. 170 (6): 353. Bibcode:2025AJ....170..353F. doi:10.3847/1538-3881/ae0cc9. ISSN 0004-6256. S2CID 283347135.
1 2 Zeigler, K. W.; Florence, W. B. (June 1985), "Photoelectric photometry of asteroids 9 Metis, 18 Melpomene, 60 Echo, 116 Sirona, 230 Athamantis, 694 Ekard, and 1984 KD", Icarus, vol. 62, no. 3, pp. 512–517, Bibcode:1985Icar...62..512Z, doi:10.1016/0019-1035(85)90191-5.
↑ Shevchenko, Vasilij G.; Tedesco, Edward F. (September 2006), "Asteroid albedos deduced from stellar occultations", Icarus, 184 (1): 211–220, Bibcode:2006Icar..184..211S, doi:10.1016/j.icarus.2006.04.006.

External links

The Asteroid Orbital Elements Database
Minor Planet Discovery Circumstances
Asteroid Lightcurve Data File
230 Athamantis at AstDyS-2, Asteroids—Dynamic Site
- Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
230 Athamantis at the JPL Small-Body Database
- Close approach · Discovery · Ephemeris · Orbit viewer · Orbit parameters · Physical parameters

This article about an S-type asteroid native to the asteroid belt is a stub. You can help Wikipedia by adding missing information.

[4] Flattening derived from the maximum aspect ratio (c/a): $f=1-{\frac {c}{a}}$ , where (c/a) = 0.76±0.07.

[6] Calculated from its standard gravitational parameter GM = 0.132±0.011 km³/s².

[7] Assuming a diameter of 118 ± 2 km.

[jpldata-1] 1 2 3 4 5 "230 Athamantis". JPL Small-Body Database. NASA/Jet Propulsion Laboratory. Retrieved 12 May 2016.

[VLT-2] 1 2 3 P. Vernazza et al. (2021) VLT/SPHERE imaging survey of the largest main-belt asteroids: Final results and synthesis. Astronomy & Astrophysics 54, A56

[Carry2012-3] Carry, B. (December 2012), "Density of asteroids", Planetary and Space Science, vol. 73, pp. 98–118, arXiv:1203.4336, Bibcode:2012P&SS...73...98C, doi:10.1016/j.pss.2012.03.009. See Table 1.

[Fuentes-Muñoz2025-5] 1 2 Fuentes-Muñoz, Oscar; Farnocchia, Davide; Giorgini, Jon D.; Park, Ryan S. (1 December 2025). "Asteroid Mass Estimation by Mutual Perturbations During Close Encounters After Gaia Focused Product Release". The Astronomical Journal. 170 (6): 353. Bibcode:2025AJ....170..353F. doi:10.3847/1538-3881/ae0cc9. ISSN 0004-6256. S2CID 283347135.

[Zeigler1985-8] 1 2 Zeigler, K. W.; Florence, W. B. (June 1985), "Photoelectric photometry of asteroids 9 Metis, 18 Melpomene, 60 Echo, 116 Sirona, 230 Athamantis, 694 Ekard, and 1984 KD", Icarus, vol. 62, no. 3, pp. 512–517, Bibcode:1985Icar...62..512Z, doi:10.1016/0019-1035(85)90191-5.

[Shevchenko_Tedesco_2006-9] Shevchenko, Vasilij G.; Tedesco, Edward F. (September 2006), "Asteroid albedos deduced from stellar occultations", Icarus, 184 (1): 211–220, Bibcode:2006Icar..184..211S, doi:10.1016/j.icarus.2006.04.006.