103 Hera

103 Hera
Discovery
Discovered by	James Craig Watson[1]
Discovery date	7 September 1868[1]
Designations
MPC designation	(103) Hera
Pronunciation	/ˈhɪərə/[2]
Named after	Hera
Alternative designations	1927 CV, 1950 CM
Minor planet category	Main belt
Orbital characteristics[3]
	Epoch 31 July 2016 (JD 2457600.5)[1]
	Uncertainty parameter 0
Observation arc	144.99 yr (52958 d)
Aphelion	2.92042 AU (436.889 Gm)[1]
Perihelion	2.48175 AU (371.265 Gm)[1]
Semi-major axis	2.70109 AU (404.077 Gm)[1]
Eccentricity	0.0812034[1]
Orbital period	4.44 yr (1621.5 d)[1]
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	7.9×1017 kg
Equatorial surface gravity	0.0255 m/s²
Equatorial escape velocity	0.0482 km/s
Rotation period	23.740 h (0.9892 d)[3]; 0.9892 d[4]
Geometric albedo	0.1833±0.025
Temperature	~170 K
Spectral type	S[5]
Absolute magnitude (H)	7.66

Hera (minor planet designation: 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 September 7, 1868,[6] and named after Hera, queen and fifth in power of the Olympian gods in Greek mythology. This is a stony S-type asteroid[5] 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.[4]

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.[7]

References

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.)
Yeomans, Donald K., "103 Hera", JPL Small-Body Database Browser, NASA Jet Propulsion Laboratory, retrieved 12 May 2016.
Pilcher, Frederick (January 2011), "Rotation Period Determination for 103 Hera", The Minor Planet Bulletin, 38 (1), p. 32, Bibcode:2011MPBu...38...32P.
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 diagram · Orbital elements · Physical parameters

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

[Pilcher2011-4] Pilcher, Frederick (January 2011), "Rotation Period Determination for 103 Hera", The Minor Planet Bulletin, 38 (1), p. 32, Bibcode:2011MPBu...38...32P.

[DeMeo2011-5] 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-6] "Numbered Minor Planets 1–5000", Discovery Circumstances, IAU Minor Planet center, retrieved 7 April 2013.

[2012arXiv1204-7] Ryan, Erin Lee; et al. (April 2012), "The Kilometer-Sized Main Belt Asteroid Population as Revealed by Spitzer", arXiv:1204.1116 [astro-ph.EP].