17 Thetis: Difference between revisions
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== External links == |
== External links == |
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{{commons category|17 Thetis}} |
{{commons category|17 Thetis}} |
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* [http://ssd.jpl.nasa.gov/horizons.cgi?find_body=1&body_group=sb&sstr=17 JPL Ephemeris] |
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* {{cite web |title=Elements and Ephemeris for (17) Thetis |publisher=Minor Planet Center |url=http://scully.cfa.harvard.edu/cgi-bin/returnprepeph.cgi?d=b2011&o=00017 }} (displays [[Elongation (astronomy)|Elong]] from Sun and [[apparent magnitude|V mag]] for 2011) |
* {{cite web |title=Elements and Ephemeris for (17) Thetis |publisher=Minor Planet Center |url=http://scully.cfa.harvard.edu/cgi-bin/returnprepeph.cgi?d=b2011&o=00017 }} (displays [[Elongation (astronomy)|Elong]] from Sun and [[apparent magnitude|V mag]] for 2011) |
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* [http://www.asteroidoccultation.com/observations/Results/Data2011/Thetis_withModel2Rotated2.jpg 2011-Apr-22 Occultation] (Durech Model) / [http://www.asteroidoccultation.com/observations/Results/index2011.html (2011 Asteroidal Occultation Results for North America)] |
* [http://www.asteroidoccultation.com/observations/Results/Data2011/Thetis_withModel2Rotated2.jpg 2011-Apr-22 Occultation] (Durech Model) / [http://www.asteroidoccultation.com/observations/Results/index2011.html (2011 Asteroidal Occultation Results for North America)] |
Revision as of 01:58, 22 December 2013
![]() Star field showing asteroid Thetis in the center | |
Discovery | |
---|---|
Discovered by | R. Luther |
Discovery date | April 17, 1852 |
Designations | |
Pronunciation | /ˈθiːt[invalid input: 'ɨ']s/ THEE-tis |
Named after | Thetis |
A913 CA; A916 YF; 1954 SO1 | |
Main belt | |
Adjectives | Thetidian |
Symbol | File:17 Thetis symbol.png |
Orbital characteristics[1] | |
Epoch October 22, 2004 (JD 2453300.5) | |
Aphelion | 419.069 Gm (2.801 AU) |
Perihelion | 319.991 Gm (2.139 AU) |
369.530 Gm (2.470 AU) | |
Eccentricity | 0.134 |
1418.027 d (3.88 a) | |
Average orbital speed | 18.87 km/s |
38.435° | |
Inclination | 5.587° |
125.622° | |
135.906° | |
Physical characteristics | |
Dimensions | 90 ± 3.7 km (IRAS)[1] |
Mass | 1.2×1018 kg[2][3] |
Mean density | 3.21 ± 0.92 g/cm³[2] |
0.0252 m/s² | |
0.0476 km/s | |
0.5113 d (12.27 h)[1][4] | |
Albedo | 0.1715[1][5] |
Temperature | ~173 K |
Spectral type | S[1] |
9.89 to 13.51[6] | |
7.76[1] | |
17 Thetis is a large main-belt asteroid that was discovered by R. Luther on April 17, 1852. It was his first asteroid discovery. The name comes from Thetis, the mother of Achilles in Greek mythology.[7]
One Thetidian stellar occultation was observed from Oregon in 1999. However, the event was not timed.
The spectrum of this object indicates that it is an S-type asteroid with both low and high calcium forms of pyroxene on the surface, along with less than 20% olivine. The high-calcium form of pyroxene forms 40% or more of the total pyroxene present, indicating a history of igneous rock depopsits. This suggests that the asteroid underwent differentiation by melting, creating a surface of basalt rock.[8]
Mass
The mass of Thetis has been calculated from perturbations by 4 Vesta and 11 Parthenope. In 2007, Baer and Chesley calculated Thetis to have a mass of 1.2×1018 kg[2][3] with a density of 3.21 g/cm³.[2]
References
- ^ a b c d e f "JPL Small-Body Database Browser: 17 Thetis". 2008-08-04 last obs. Retrieved 2008-11-12.
{{cite web}}
: Check date values in:|date=
(help) - ^ a b c d Baer, James; Steven R. Chesley (2007). "Astrometric masses of 21 asteroids, and an integrated asteroid ephemeris" (PDF). Celestial Mechanics and Dynamical Astronomy. 100 (2008). Springer Science+Business Media B.V. 2007: 27–42. Bibcode:2008CeMDA.100...27B. doi:10.1007/s10569-007-9103-8. Retrieved November 12, 2008.
- ^ a b (Mass of Thetis 0.00617 / Mass of Ceres 4.75) * Mass of Ceres 9.43E+20 = 1.224E+18
- ^ "LIGHTCURVES AND MAP DATA ON NUMBERED ASTEROIDS N° 1 TO 52225". AstroSurf. Archived from the original on November 27, 2005. Retrieved November 3, 2008.
- ^ "Asteroid Data Archive". Planetary Science Institute. Archived from the original on June 23, 2006. Retrieved November 3, 2008.
- ^ apmag 9.89 (1977-Jul-25) to 13.51 (1963-Aug-02) JPL Horizons daily output for 1950 to 2099
- ^ Schmadel, Lutz D. (2003). Dictionary of minor planet names, Volume 1 (5th ed.). Berlin Heidelberg New York: Springer-Verlag. p. 17. ISBN 3-540-00238-3.
- ^ Sunshine, Richard P.; et al. (August 2004), "High-calcium pyroxene as an indicator of igneous differentiation in asteroids and meteorites", Meteoritics & Planetary Science, vol. 39, no. 8, pp. 1343–1357, Bibcode:2004M&PS...39.1343S, doi:10.1111/j.1945-5100.2004.tb00950.x.
External links
![](http://upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/30px-Commons-logo.svg.png)
- JPL Ephemeris
- "Elements and Ephemeris for (17) Thetis". Minor Planet Center. (displays Elong from Sun and V mag for 2011)
- 2011-Apr-22 Occultation (Durech Model) / (2011 Asteroidal Occultation Results for North America)