13 Egeria
Wikipedia on Answers.com:
Top
13 Egeria
|
Discovery
|
|
|---|---|
| Discovered by | Annibale de Gasparis |
| Discovery date | November 2, 1850 |
|
Designations
|
|
| Alternate name(s) | none |
| Minor planet category |
Main belt |
| Epoch July 14, 2004 (JD 2453200.5) | |
| Aphelion | 417.953 Gm (2.794 AU) |
| Perihelion | 352.719 Gm (2.358 AU) |
| Semi-major axis | 385.336 Gm (2.576 AU) |
| Eccentricity | 0.085 |
| Orbital period | 1509.977 d (4.13 a) |
| Average orbital speed | 18.56 km/s |
| Mean anomaly | 339.787° |
| Inclination | 16.540° |
| Longitude of ascending node | 43.305° |
| Argument of perihelion | 81.401° |
|
Physical characteristics
|
|
| Dimensions | 207.6 ± 8.3 km (IRAS)[1] (217×196 km) |
| Mass | 1.63×1019 kg[2] |
| Mean density | 3.46±0.79 g/cm³[2] |
| Equatorial surface gravity | ~0.0580 m/s² |
| Escape velocity | ~0.1098 km/s |
| Rotation period | 0.2935 d[3] (7.045 h)[1] |
| Albedo | 0.083[1][4] |
| Temperature | ~174 K |
| Spectral type | G-type asteroid[1] |
| Apparent magnitude | 9.71 to 12.46[5] |
| Absolute magnitude (H) | 6.74[1] |
13 Egeria (
/ɨˈdʒɪəriə/ i-JEER-ee-ə; Latin: Ægeria)[missing vowel length] is a large main-belt G-type asteroid.[6]
It was discovered by A. de Gasparis on November 2, 1850, and was named by Urbain J. J. Le Verrier, whose computations led to the discovery of Neptune. Egeria was a goddess (other sources say a nymph) of Aricia, in Italy, and the wife of Numa Pompilius, second king of Rome.[7]
Egeria occulted a star on January 8, 1992. The former's disc was determined to be quite circular (217×196 km).
On January 22, 2008, Egeria occulted another star and this occultation was timed by several observers in New Mexico and Arizona, coordinated by the IOTA Asteroid Occultation Program.[8] The data was entered into the OCCULT4 estimation and visualization program written by Dave Herald of Canberra, Australia. The result showed that Egeria presented an approximately circular profile to Earth of 214.8x192 km, well in agreement with the 1992 occultation.
Egeria has been studied by radar.[9]
High water content
Spectral analysis of Egeria shows it to be unusually high in water content, between 10.5-11.5% water by mass.[10] This makes Egeria a prominent candidate for future water-mining ventures.
Notes
- ^ a b c d e f "JPL Small-Body Database Browser: 13 Egeria". 2008-11-04 last obs. http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=13. Retrieved 2008-11-25.
- ^ a b Jim Baer (2008). "Recent Asteroid Mass Determinations". Personal Website. http://home.earthlink.net/~jimbaer1/astmass.txt. Retrieved 2008-11-28.
- ^ "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 9.71 (2061-Nov-06) to 12.46 (1990-Mar-12) JPL Horizons daily output for 1950 to 2099
- ^ Rivkin, A. S.; J. K. Davies, S. L. Ellison, L. A. Lebofsky. "High-resolution 2.5–3.5 �M Observations of C-, B- and G-class asteroids." (PDF). http://www.lpi.usra.edu/meetings/LPSC98/pdf/1310.pdf. Retrieved 2008-04-20.
- ^ Schmadel, Lutz D. (2003). Dictionary of minor planet names, Volume 1 (5th ed.). Berlin Heidelberg New York: Springer-Verlag. pp. 16. ISBN 3-540-00238-3.
- ^ Timerson, Brad. "IOTA Asteroid Occultation Results for 2008". http://www.asteroidoccultation.com/observations/Results/index2008.html. Retrieved 2010-01-19. (Chords)
- ^ "Radar-Detected Asteroids and Comets". NASA/JPL Asteroid Radar Research. http://echo.jpl.nasa.gov/asteroids/. Retrieved 2011-10-30.
- ^ http://www.lpi.usra.edu/meetings/lpsc2002/pdf/1414.pdf
External links
- Orbital simulation from JPL (Java) / JPL Horizons Ephemeris
- "Elements and Ephemeris for (13) Egeria". Minor Planet Center. http://scully.cfa.harvard.edu/cgi-bin/returnprepeph.cgi?d=b2011&o=00013. (displays Elong from Sun and V mag for 2011)
|
|||||
|
||||||||||||||||||||||
This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)
Post a question - any question - to the WikiAnswers community:
Copyrights:
Wikipedia on Answers.com
This article is licensed under the Creative Commons Attribution/Share-Alike License. It uses material from the Wikipedia article 13 Egeria.
Read more