| Minorplanet | yes |
|---|---|
| Background |
|
| Discoverer | Paul Henry and Prosper Henry |
| Discovered | 5 November 1872 |
| Mpc name | (127) Johanna |
| Alt names | A872 VB |
| Pronounced | /dʒoʊ-hænə/[1] |
| Named after | Joan of Arc |
| Mp category | Main belt |
| Epoch | 31 July 2016 (JD 2457600.5) |
| Semimajor | 2.75615 AU (412.31 Gm) |
| Perihelion | 2.57138 AU (384.67 Gm) |
| Aphelion | 2.9409 AU (439.95 Gm) |
| Eccentricity | 0.067041 |
| Period | 1,671.3 days |
| Inclination | 8.2449° |
| Asc node | 31.154° |
| Arg peri | 94.611° |
| Mean anomaly | 67.782° |
| Avg speed | 17.92 km/s |
| Dimensions | 122[2] 116.14 ± 3.93 km[3] |
| Mass | (3.08 ± 1.35) × 1018 kg[3] |
| Density | 3.75 ± 1.68 g/cm3[3] |
| Rotation | 12.7988 h[2][4] |
| Abs magnitude | 8.6,[2] 8.30[5] |
| Albedo | 0.0557 ± 0.0039[5] |
| Single temperature | ~168 K |
| Mean motion | / day |
| Observation arc | 98.53 yr (35989 d) |
| Uncertainty | 0 |
| Moid | 1.60141 AU (239.57 Gm) |
| Jupiter moid | 2.11199 AU (315.95 Gm) |
| Tisserand | 3.325 |
127 Johanna is a large, dark main-belt asteroid that was discovered by French astronomers Paul Henry and Prosper Henry on 5 November 1872, and is believed to be named after Joan of Arc.[6] It is classified as a CX-type asteroid, indicating the spectrum shows properties of both a carbonaceous C-type asteroid and a metallic X-type asteroid.[7]
A photoelectric study was performed of this minor planet in 1991 at the Konkoly Observatory in Hungary. The resulting light curve showed a synodic rotation period of 6.94 ± 0.29 hours with a brightness variation of 0.2 in magnitude. It was estimated to have an absolute magnitude of 8.459 ± 0.013 with a diameter of 96-118 km and an albedo of 0.06–0.04.[8]
Infrared observations made in 1982 at Konkoly showed a rapid variation that seemed to suggest a shorter rotation period of 1.5 hours; one of the fastest known at the time. However, an irregular shape was suggested as an alternative cause of the rapid variation.[9] The present day established rotation period of this object is 12.7988 hours.[4]
During 2001, 127 Johanna was observed by radar from the Arecibo Observatory. The return signal matched an effective diameter of 117 ± 21 km.[7] A larger diameter value of 123.41 ± 4.07 km was obtained from the Midcourse Space Experiment observations, with an albedo of 0.0557 ± 0.0039.[5] A 2012 study gave a refined diameter estimate of 116.14 ± 3.93 km.[3]
References
- ^ Noah Webster (1884) A Practical Dictionary of the English Language
- ^ Yeomans, Donald K., "127 Johanna", JPL Small-Body Database Browser, NASA Jet Propulsion Laboratory, retrieved 12 May 2016
- ^ 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.
- ^ Behrend, Raoul, "Courbes de rotation d'astéroïdes et de comètes" (in French), Observatoire de Genève, retrieved 2013-03-29
- ^ Tedesco, Edward F. et al. (July 2002), "The Midcourse Space Experiment Infrared Minor Planet Survey", The Astronomical Journal. Vol. 124, no. 124, pp. 583–591, Bibcode:2002AJ....124..583T. doi:10.1086/340960
- ^ Schmadel, Lutz D. & International Astronomical Union (2003), Dictionary of minor planet names, Berlin; New York: Springer-Verlag, p. 27, ISBN 978-3-540-00238-3
- ^ Magri, Christopher et al. (January 2007), "A radar survey of main-belt asteroids: Arecibo observations of 55 objects during 1999–2003", Icarus. 186 (1): 126–151, Bibcode:2007Icar..186..126M. doi:10.1016/j.icarus.2006.08.018
- ^ Toth, Imre (December 1997), "First lightcurve observations and rotation of minor planet 127 Johanna", Planetary and Space Science. Vol. 45, pp. 1625–1637, Bibcode:1997P&SS...45.1625T. doi:10.1016/S0032-0633(97)00141-4
- ^ Szecsenyi-Nagy, G. (1983), "127 Johanna - Is it really the most quickly spinning asteroid known at this moment?", Asteroids, comets, meteors; Proceedings of the Meeting, Uppsala, Sweden, June 20–22, 1983. Vol. 45, pp. 49–53, Bibcode:1983acm..proc...49S. doi:10.1016/S0032-0633(97)00141-4