17 Thetis
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Star field showing asteroid Thetis in the center
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Discovery
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| Discovered by | R. Luther |
| Discovery date | April 17, 1852 |
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Designations
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| Named after | Thetis |
| Alternate name(s) | A913 CA; A916 YF; 1954 SO1 |
| Minor planet category |
Main belt |
| Adjective | Thetidian |
| Epoch October 22, 2004 (JD 2453300.5) | |
| Aphelion | 419.069 Gm (2.801 AU) |
| Perihelion | 319.991 Gm (2.139 AU) |
| Semi-major axis | 369.530 Gm (2.470 AU) |
| Eccentricity | 0.134 |
| Orbital period | 1418.027 d (3.88 a) |
| Average orbital speed | 18.87 km/s |
| Mean anomaly | 38.435° |
| Inclination | 5.587° |
| Longitude of ascending node | 125.622° |
| Argument of perihelion | 135.906° |
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Physical characteristics
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| Dimensions | 90 ± 3.7 km (IRAS)[1] |
| Mass | 1.2×1018 kg[2][3] |
| Mean density | 3.21 ± 0.92 g/cm³[2] |
| Equatorial surface gravity | 0.0252 m/s² |
| Escape velocity | 0.0476 km/s |
| Rotation period | 0.5113 d (12.27 h)[1][4] |
| Albedo | 0.1715 [1][5] |
| Temperature | ~173 K |
| Spectral type | S[1] |
| Apparent magnitude | 9.89 to 13.51[6] |
| Absolute magnitude (H) | 7.76[1] |
17 Thetis (
/ˈθiːtɨs/; Greek: Θέτις) is a large main-belt asteroid. It is an S-type asteroid, therefore giving it a relatively bright silicate surface.
It was discovered by R. Luther on April 17, 1852. It was his first asteroid discovery. Its 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.
[edit] 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]
[edit] Notes
- ^ a b c d e f "JPL Small-Body Database Browser: 17 Thetis". 2008-08-04 last obs. http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=17. Retrieved 2008-11-12.
- ^ 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 (Springer Science+Business Media B.V. 2007) 100 (2008): 27–42. Bibcode 2008CeMDA.100...27B. doi:10.1007/s10569-007-9103-8. http://www.springerlink.com/content/h747307j43863228/fulltext.pdf. Retrieved 2008-11-12.
- ^ 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 2005-11-27. http://web.archive.org/web/20051127063200/http://www.astrosurf.com/aude-old/map_files/AstVarMAP01-2003.htm. Retrieved 2008-11-03.
- ^ "Asteroid Data Archive". Planetary Science Institute. Archived from the original on 2006-06-23. http://web.archive.org/web/20060623213811/http://www.psi.edu/pds/archive/astdata04/simps04/diamalb.tab. Retrieved 2008-11-03.
- ^ 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. pp. 17. ISBN 3-540-00238-3.
[edit] External links
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Wikimedia Commons has media related to: 17 Thetis |
- Orbital simulation from JPL (Java) / JPL Horizons Ephemeris
- "Elements and Ephemeris for (17) Thetis". Minor Planet Center. http://scully.cfa.harvard.edu/cgi-bin/returnprepeph.cgi?d=b2011&o=00017. (displays Elong from Sun and V mag for 2011)
- 2011-Apr-22 Occultation (Durech Model) / (2011 Asteroidal Occultation Results for North America)
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