103 Hera

103 Hera
	3D convex shape model of 103 Hera
Discovery
Discovered by	James Craig Watson
Discovery date	7 September 1868
Designations
Pronunciation	/ˈhɪərə/
Named after	Hera
Alternative designations	A868 RA, 1927 CV; 1950 CM
Minor planet category	Main belt
Orbital characteristics
	Epoch 31 July 2016 (JD 2457600.5)
	Uncertainty parameter 0
Observation arc	144.99 yr (52958 d)
Aphelion	2.92042 AU (436.889 Gm)
Perihelion	2.48175 AU (371.265 Gm)
Semi-major axis	2.70109 AU (404.077 Gm)
Eccentricity	0.0812034
Orbital period (sidereal)	4.44 yr (1621.5 d)
Average orbital speed	18.09 km/s
Mean anomaly	133.341°
Mean motion	0° 13m 19.279s / day
Inclination	5.41957°
Longitude of ascending node	136.186°
Argument of perihelion	188.361°
Earth MOID	1.46898 AU (219.756 Gm)
Jupiter MOID	2.32392 AU (347.653 Gm)
TJupiter	3.356
Physical characteristics
Dimensions	91.20±5.6 km
Mass	(6.0±1.8)×1017 kg
Mean density	1.95 g/cm3
Equatorial surface gravity	0.0255 m/s²
Equatorial escape velocity	0.0482 km/s
Synodic rotation period	23.740 h (0.9892 d); 0.9892 d
Geometric albedo	0.1833±0.025
Temperature	~170 K
Spectral type	S
Absolute magnitude (H)	7.66

103 Hera is a moderately large main-belt asteroid with an orbital period of 4.44 years. It was discovered by Canadian-American astronomer James Craig Watson on 7 September 1868, and named after Hera, queen and fifth in power of the Olympian gods in Greek mythology. This is a stony S-type asteroid with a silicate surface composition.

Photometric observations made in 2010 at the Organ Mesa Observatory at Las Cruces, New Mexico, and the Hunters Hill Observatory at Ngunnawal, Australian Capital Territory, give a synodic rotation period of 23.740±0.001 h. The bimodal light curve shows a maximum brightness variation of 0.45 ± 0.03 in magnitude.

Measurements made with the IRAS observatory give a diameter of 91.58±4.14 km and a geometric albedo of 0.19±0.02. By comparison, the MIPS photometer on the Spitzer Space Telescope gives a diameter of 88.30±8.51 km and a geometric albedo of 0.20±0.04. When the asteroid was observed occulting a star, the chords showed a diameter of 89.1±1.1 km.

Notes

↑ Calculated from its standard gravitational parameter GM = 0.040±0.012 km³/s².
↑ Assuming a diameter of 83.9 km.

References

1 2 3 4 5 6 7 8 JPL Small-Body Database Browser, JPL, retrieved 30 October 2020
↑ "Hera". Oxford English Dictionary (online ed.). Oxford University Press. (Subscription or participating institution membership required.)
1 2 Yeomans, Donald K., "103 Hera", JPL Small-Body Database Browser, NASA Jet Propulsion Laboratory, retrieved 12 May 2016.
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 Pilcher, Frederick (January 2011), "Rotation Period Determination for 103 Hera", The Minor Planet Bulletin, 38 (1): 32, Bibcode:2011MPBu...38...32P.
1 2 DeMeo, Francesca E.; et al. (2011), "An extension of the Bus asteroid taxonomy into the near-infrared" (PDF), Icarus, 202 (1): 160–180, Bibcode:2009Icar..202..160D, doi:10.1016/j.icarus.2009.02.005, archived from the original (PDF) on 17 March 2014, retrieved 22 March 2013. See appendix A.
↑ "Numbered Minor Planets 1–5000", Discovery Circumstances, IAU Minor Planet center, retrieved 7 April 2013.
↑ Ryan, Erin Lee; et al. (April 2012), "The Kilometer-Sized Main Belt Asteroid Population as Revealed by Spitzer", arXiv:1204.1116 [astro-ph.EP]

External links

103 Hera at AstDyS-2, Asteroids—Dynamic Site
- Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
103 Hera 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.

[5] Calculated from its standard gravitational parameter GM = 0.040±0.012 km³/s².

[6] Assuming a diameter of 83.9 km.

[JPLBrowser-1] 1 2 3 4 5 6 7 8 JPL Small-Body Database Browser, JPL, retrieved 30 October 2020

[2] "Hera". Oxford English Dictionary (online ed.). Oxford University Press. (Subscription or participating institution membership required.)

[JPL-3] 1 2 Yeomans, Donald K., "103 Hera", JPL Small-Body Database Browser, NASA Jet Propulsion Laboratory, retrieved 12 May 2016.

[Fuentes-Muñoz2025-4] 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.

[Pilcher2011-7] 1 2 Pilcher, Frederick (January 2011), "Rotation Period Determination for 103 Hera", The Minor Planet Bulletin, 38 (1): 32, Bibcode:2011MPBu...38...32P.

[DeMeo2011-8] 1 2 DeMeo, Francesca E.; et al. (2011), "An extension of the Bus asteroid taxonomy into the near-infrared" (PDF), Icarus, 202 (1): 160–180, Bibcode:2009Icar..202..160D, doi:10.1016/j.icarus.2009.02.005, archived from the original (PDF) on 17 March 2014, retrieved 22 March 2013. See appendix A.

[IAU_MPC-9] "Numbered Minor Planets 1–5000", Discovery Circumstances, IAU Minor Planet center, retrieved 7 April 2013.

[2012arXiv1204-10] Ryan, Erin Lee; et al. (April 2012), "The Kilometer-Sized Main Belt Asteroid Population as Revealed by Spitzer", arXiv:1204.1116 [astro-ph.EP]