Astronomy:42355 Typhon
 Hubble Space Telescope image of Typhon and its moon Echidna, taken in 2006 | |
| Discovery | |
|---|---|
| Discovered by | NEAT |
| Discovery date | 5 February 2002 |
| Designations | |
| (42355) Typhon | |
| Pronunciation | /ˈtaɪfɒn/[4] |
| Named after | Τυφών Typhōn |
| 2002 CR46 | |
| Minor planet category | SDO[1][2] Centaur[3] |
| Adjectives | Typhonian /taɪˈfoʊniən/[5] |
| Orbital characteristics[1] | |
| Epoch 13 January 2016 (JD 2457400.5) | |
| Uncertainty parameter 2 | |
| Observation arc | 9563 days (26.18 yr) |
| |{{{apsis}}}|helion}} | 58.982252 astronomical unit|AU (8.8236193 Tm) |
| |{{{apsis}}}|helion}} | 17.545721 AU (2.6248025 Tm) |
| 38.263987 AU (5.7242110 Tm) | |
| Eccentricity | 0.5414560 |
| Orbital period | 236.70 yr (86453.7 d) |
| Mean anomaly | 14.61898075° |
| Mean motion | 0° 0m 14.991s / day |
| Inclination | 2.4252078° |
| Longitude of ascending node | 351.9098598° |
| 159.3215723° | |
| Known satellites | 1 (Echidna) |
| TJupiter | 4.692 |
| Physical characteristics | |
| Mean diameter | 162±7 km[6] |
| Mass | (9.49±0.52)×1017 kg[7] |
| Mean density | 0.66+0.09 −0.08 g/cm3[8] |
| Rotation period | 9.67 h (0.403 d)[8] |
| Geometric albedo | 0.044±0.003[6] |
| B−R=1.29±0.07[6] V−I=0.99±0.04[7] | |
| Absolute magnitude (H) | 7.72±0.004[6] |
42355 Typhon (/ˈtaɪfɒn/; provisional designation 2002 CR46) is a scattered disc object that was discovered on February 5, 2002, by the NEAT program. It measures 162±7 km in diameter, and is named after Typhon, a monster in Greek mythology. Typhon is the first known binary centaur,[9] using an extended definition of a centaur as an object on a non-resonant (unstable) orbit with the perihelion inside the orbit of Neptune.[10]
Symbol
Planetary symbols are no longer much used in astronomy, so Typhon never received a symbol in the astronomical literature. There is no standard symbol for Typhon used by astrologers either. A hurricane symbol (16px) has been used, which might be identified with U+1F300 🌀 (U+FE0E ︎ [[|]] is used to make the character display as text).[11]
Physical properties
Measurements of its thermal radiation led to an equivalent diameter of about either 138±9 km or 185±7 km, with the latter value preferable.[8] The diameter of the central body (Typhon) is in the latter case 162±7 km.[6] Due to its small size, it is unlikely to be classified as a dwarf planet. As of 2021, no rotational lightcurve has been analyzed and the body's actual shape remain unknown.
Typhon has a BR taxonomic class, with a blue surface. It has a resulting B–R color difference of about 1.3,[6] while V–I color difference is about unity.[7] The spectra of Typhon show the presence of water ice and possibly of water altered silicates.[12]
Satellite
| Discovery | |
|---|---|
| Discovery date | 2006 |
| Designations | |
| (42355) Typhon I | |
| Pronunciation | /ɪˈkɪdnə/[13] |
| Named after | Έχιδνα |
| Adjectives | Echidnian[14] Echidnean (rarely)[15] (both /ɪˈkɪdniən/)[16] |
| Orbital characteristics | |
| ~1300 km | |
| Orbital period | 11 d |
| Satellite of | Typhon |
| Physical characteristics | |
| Dimensions | 89±6 km |
A large moon was identified in 2006.[7] It is named Echidna (formal designation (42355) Typhon I), after the monstrous mate of Typhon. It orbits Typhon at the distance of 1628±29 km, completing one orbit in 18.9709±0.0064 days. Its diameter is estimated at 89±6 km.[6] Echidna has the same color as Typhon.[7]
References
- ↑ 1.0 1.1 "JPL Small-Body Database Browser: (42355 Typhon)". https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=42355.
- ↑ "List Of Centaurs and Scattered-Disk Objects". Minor Planet Center. http://www.minorplanetcenter.org/iau/lists/Centaurs.html.
- ↑ (42355) Typhon and Echidna
- ↑ Typhon (3rd ed.), Oxford University Press, September 2005, http://oed.com/search?searchType=dictionary&q=Typhon (Subscription or UK public library membership required.)
- ↑ Typhonian (3rd ed.), Oxford University Press, September 2005, http://oed.com/search?searchType=dictionary&q=Typhonian (Subscription or UK public library membership required.)
- ↑ 6.0 6.1 6.2 6.3 6.4 6.5 6.6 Santos-Sanz, P.; Lellouch, E.; Fornasier, S. et al. (May 2012). "“TNOs are Cool”: A survey of the trans-Neptunian region: IV. Size/albedo characterization of 15 scattered disk and detached objects observed with Herschel -PACS⋆⋆⋆". Astronomy & Astrophysics 541: A92. doi:10.1051/0004-6361/201118541.
- ↑ 7.0 7.1 7.2 7.3 7.4 Grundy, W; Noll, K; Virtanen, J; Muinonen, K; Kern, S; Stephens, D; Stansberry, J; Levison, H et al. (September 2008). "(42355) Typhon–Echidna: Scheduling observations for binary orbit determination". Icarus 197 (1): 260–268. doi:10.1016/j.icarus.2008.04.004.
- ↑ 8.0 8.1 8.2 Duffard, R.; Pinilla-Alonso, N.; Santos-Sanz, P.; Vilenius, E.; Ortiz, J. L.; Mueller, T. et al. (April 2014). ""TNOs are Cool": A survey of the trans-Neptunian region. XI. A Herschel-PACS view of 16 Centaurs". Astronomy and Astrophysics 564: 17. doi:10.1051/0004-6361/201322377. Bibcode: 2014A&A...564A..92D.
- ↑ K. Noll; H. Levison; W. Grundy; D. Stephens (October 2006). "Discovery of a binary Centaur". Icarus 184 (2): 611. doi:10.1016/j.icarus.2006.05.010. Bibcode: 2006Icar..184..611N.
- ↑ J. L. Elliot; S. D. Kern; K. B. Clancy; A. A. S. Gulbis; R. L. Millis; M. W. Buie et al. (February 2005). "The Deep Ecliptic Survey: A Search for Kuiper Belt Objects and Centaurs. II. Dynamical Classification, the Kuiper Belt Plane, and the Core Population". The Astronomical Journal 129 (2): 1117. doi:10.1086/427395. Bibcode: 2005AJ....129.1117E. http://occult.mit.edu/_assets/documents/publications/Elliot2005AJ129.1117.pdf.
- ↑ Bala, Gavin Jared; Miller, Kirk (18 September 2023). "Unicode request for historical asteroid symbols". Unicode. https://www.unicode.org/L2/L2023/23207-historical-asteroids.pdf.
- ↑ Alvarez-Candal, A.; Barucci, M. A.; Merlin, F.; de Bergh, C.; Fornasier, S.; Guilbert, A.; Protopapa, S. (February 2010). "The trans-Neptunian object (42355) Typhon: composition and dynamical evolution". Astronomy and Astrophysics 511: A35. doi:10.1051/0004-6361/200913102.
- ↑ Echidna (3rd ed.), Oxford University Press, September 2005, http://oed.com/search?searchType=dictionary&q=Echidna (Subscription or UK public library membership required.)
- ↑ François Hartog (Janet Lloyd, trans., 1988) The Mirror of Herodotus, p. 25
- ↑ J. A. Weinstock (2014) The Ashgate Encyclopedia of Literary and Cinematic Monsters, p. 79
- ↑ George Sandys (1669) Ovid's Metamorphosis Englished, 6th ed., p. 134.
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