Astronomy:103 Hera
_Hera.png) 3D convex shape model of 103 Hera | |
| Discovery | |
|---|---|
| Discovered by | James Craig Watson[1] |
| Discovery date | 7 September 1868[1] |
| Designations | |
| (103) Hera | |
| Pronunciation | /ˈhɪərə/[2] |
| Named after | Hera |
| A868 RA, 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) |
| |{{{apsis}}}|helion}} | 2.92042 astronomical unit|AU (436.889 Gm)[1] |
| |{{{apsis}}}|helion}} | 2.48175 AU (371.265 Gm)[1] |
| 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° |
| 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 |
| Physics | ~170 K |
| 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
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 JPL Small-Body Database Browser, JPL, http://ssd.jpl.nasa.gov/sbdb.cgi#top, retrieved 2020-10-30
- ↑ Hera (3rd ed.), Oxford University Press, September 2005, http://oed.com/search?searchType=dictionary&q=Hera (Subscription or UK public library membership required.)
- ↑ 3.0 3.1 Yeomans, Donald K., "103 Hera", JPL Small-Body Database Browser (NASA Jet Propulsion Laboratory), https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=103, retrieved 12 May 2016.
- ↑ 4.0 4.1 Pilcher, Frederick (January 2011), "Rotation Period Determination for 103 Hera", The Minor Planet Bulletin 38 (1): 32, Bibcode: 2011MPBu...38...32P.
- ↑ 5.0 5.1 DeMeo, Francesca E. et al. (2011), "An extension of the Bus asteroid taxonomy into the near-infrared", Icarus 202 (1): 160–180, doi:10.1016/j.icarus.2009.02.005, Bibcode: 2009Icar..202..160D, archived from the original on 2014-03-17, https://web.archive.org/web/20140317200310/https://www.tara.tcd.ie/bitstream/2262/43276/1/PEER_stage2_10.1016/j.icarus.2009.02.005.pdf, retrieved 2013-03-22. See appendix A.
- ↑ "Numbered Minor Planets 1–5000", Discovery Circumstances (IAU Minor Planet center), https://www.minorplanetcenter.net/iau/lists/NumberedMPs000001.html, retrieved 2013-04-07.
- ↑ 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
- 103 Hera at the JPL Small-Body Database
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