127 Johanna
.png) A three-dimensional model of 127 Johanna based on its light curve | |
| Discovery | |
|---|---|
| Discovered by | Paul Henry and Prosper Henry |
| Discovery date | 5 November 1872 |
| Designations | |
| (127) Johanna | |
| Pronunciation | /dʒoʊˈhænə/[1] |
Named after | Joan of Arc |
| A872 VB | |
| Main belt | |
| Orbital characteristics[2] | |
| Epoch 31 July 2016 (JD 2457600.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 98.53 yr (35989 d) |
| Aphelion | 2.94 |
| Perihelion | 2.57 |
| 2.76 | |
| Eccentricity | 0.067041 |
| 4.58 yr (1,671.3 d) | |
Average orbital speed | 17.92 km/s |
| 67.782° | |
| 0° 12m 55.44s / day | |
| Inclination | 8.2449° |
| 31.154° | |
| 94.611° | |
| Earth MOID | 1.60 |
| Jupiter MOID | 2.11 |
| TJupiter | 3.325 |
| Physical characteristics | |
| Dimensions | 122[2] 116.14±3.93 km[3] |
| Mass | (3.08 ± 1.35) × 1018 kg[3] |
Mean density | 3.75±1.68 g/cm3[3] |
| 12.7988 h (0.53328 d)[2][4] | |
| 0.0557±0.0039[5] | |
| Temperature | ~168 K |
| CX[6] (Tholen) Ch[6] (Bus) | |
| 8.6,[2] 8.30[5] | |
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.[7] 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.[6]
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 (60–73 mi) 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.[6] 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
[edit]- ^ Noah Webster (1884) A Practical Dictionary of the English Language
- ^ a b c d Yeomans, Donald K., "127 Johanna", JPL Small-Body Database Browser, NASA Jet Propulsion Laboratory, retrieved 12 May 2016.
- ^ a b c d 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.
- ^ a b Behrend, Raoul, Courbes de rotation d'astéroïdes et de comètes (in French), Observatoire de Genève, retrieved 29 March 2013
- ^ a b c 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.
- ^ a b c d 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
- ^ 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.
- ^ 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.
External links
[edit]- 127 Johanna at AstDyS-2, Asteroids—Dynamic Site
- 127 Johanna at the JPL Small-Body Database
