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19 Fortuna

Fortuna centered above the Crab Nebula
Discovery
Discovered by	John Russell Hind
Discovery date	August 22, 1852
Designations
Alternate name	A902 UG
Minor planet category	Main belt
Orbital characteristics[1]
Epoch October 22, 2004 (JD 2453300.5)
Aphelion	423.443 Gm (2.831 AU)
Perihelion	307.028 Gm (2.052 AU)
Semi-major axis	365.235 Gm (2.441 AU)
Eccentricity	0.159
Orbital period	1393.378 d (3.81 a)
Average orbital speed	18.94 km/s
Mean anomaly	268.398°
Inclination	1.573°
Longitude of ascending node	211.379°
Argument of perihelion	182.091°
Physical characteristics
Dimensions	225x205x195km[2] 225 km[3][4]
Mass	1.27 × 1019 kg[2]
Mean density	2.70±0.48 g/cm³[2]
Equatorial surface gravity	~0.0629 m/s²
Escape velocity	~0.1190 km/s
Rotation period	0.3101 d (7.4432 h)[1]
Albedo	0.037[1]
Temperature	~180 K
Spectral type	G[1]
Apparent magnitude	8.88 to 12.95
Absolute magnitude (H)	7.13[1]
Angular diameter	0.25" to 0.072"

19 Fortuna (pronounced /fɔrˈtjuːnə/, or as in Latin: Fortūna) is one of the largest main belt asteroids. It has a composition similar to 1 Ceres: a darkly colored surface that is heavily space weathered with the composition of primitive organic compounds, including tholins.

Fortuna is 225 km in diameter and has one of the darkest known geometric albedos for an asteroid over 150 km in diameter. Its albedo has been measured at 0.028 and 0.037.^[5]

The Hubble Space Telescope observed Fortuna in 1993. It was resolved with an apparent diameter of 0.20 arcseconds (4.5 pixels in the Planetary Camera) and its shape was found to be nearly spherical. Satellites were searched for but none were detected.

Stellar occultations by Fortuna have been observed several times.

It was discovered by J. R. Hind on August 22, 1852 and named after Fortuna, the Roman goddess of luck.

Fortuna has been perturbed by the 80 km 135 Hertha and was initially estimated by Baer to have a mass of 1.08 × 10¹⁹ kg.^[4] A more recent estimate by Baer suggests it has a mass of 1.27 × 10¹⁹ kg.^[2]

On December 21, 2012 Fortuna (~200km) will harmlessly pass within 6.5Gm of asteroid 687 Tinette.^[6]

Fortuna is also the name of a planet in the video game StarFox.

References

1. ^ ^{a b c d e} "JPL Small-Body Database Browser: 19 Fortuna". 2008-08-21 last obs. http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=19. Retrieved 2008-11-11.  
2. ^ ^{a b c d} Jim Baer (2008). "Recent Asteroid Mass Determinations". Personal Website. http://home.earthlink.net/~jimbaer1/astmass.txt. Retrieved 2008-11-27.  
3. ^ Storrs, Alex; Weiss, B.; Zellner, B.; et al. (1998). "Imaging Observations of Asteroids with Hubble Space Telescope". Icarus 137: 260–268. doi:10.1006/icar.1999.6047. http://web.media.mit.edu/~win/hstpub.pdf. Retrieved 2005-01-15.  
4. ^ ^{a b} Baer, James; Steven R. Chesley (2008). "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. doi:10.1007/s10569-007-9103-8. http://www.springerlink.com/content/h747307j43863228/fulltext.pdf. Retrieved 2008-11-11.  
5. ^ Storrs, Alex; Dunne; Conan; Mugnier; et al. (2005). "A closer look at main belt asteroids 1: WF/PC images" (). Icarus 173 (2): 409–416. doi:10.1016/j.icarus.2004.08.007. http://web.mit.edu/bpweiss/www/StorrsWeiss2005AsteroidsHSTIcarus.pdf. Retrieved 2007-09-23.  
6. ^ Generated with Solex 10 by Aldo Vitagliano

External links

• Orbital simulation from JPL (Java) / Ephemeris