Astronomy:19 Fortuna

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19 Fortuna 24px (historical)
Discovery
Discovered byJohn Russell Hind
Discovery date22 August 1852
Designations
(19) Fortuna
Pronunciation/fɔːrˈtjuːnə/[1]
Named afterFortūna
A902 UG
Minor planet categoryMain belt
AdjectivesFortunian /fɔːrˈtjuːniən/
Orbital characteristics[2]
Epoch 17.0 October 2024 (JD 2460600.5)
|{{{apsis}}}|helion}}2.831 AU (423.443 Gm)
|{{{apsis}}}|helion}}2.052 AU (307.028 Gm)
2.441 AU (365.235 Gm)
Eccentricity0.159
Orbital period3.81 a (1393.378 d)
Average Orbital speed18.94 km/s
Mean anomaly268.398°
Inclination1.573°
Longitude of ascending node211.379°
182.091°
Earth MOID1.06316 AU
Jupiter MOID2.60305 AU
TJupiter3.483
Physical characteristics
Dimensions(225 × 205 × 195) ± 12 km[3]
(242 × 203 × 192) ± 10 km[4]
Mean diameter211±2 km[4]
225 km[5][6]
Flattening0.21[lower-alpha 1]
Mass(8.8±1.4)×1018 kg[4]
12.7×1018 kg[3]
Mean density1.80±0.29 g/cm3[4]
2.70±0.48 g/cm3[3]
Equatorial surface gravity
~0.0629 m/s²
Equatorial escape velocity
~0.1190 km/s
Rotation period7.4432 h (0.3101 d)[2]
7.443224±0.000001 h[4]
Axial tilt29°[4]
Pole ecliptic latitude60°±3°[4]
Pole ecliptic longitude103°±3°[4]
Geometric albedo0.056[4]
0.037[2]
Physics~180 K
G[2]
Apparent magnitude8.88[7] to 12.95
Absolute magnitude (H)7.49[2]
7.13[4]
Angular diameter0.25" to 0.072"


19 Fortuna 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.[8] The spectra of the asteroid displays evidence of aqueous alteration.[9]

Discovery and naming

It was discovered by J. R. Hind on 22 August 1852, and named after Fortuna, the Roman goddess of luck. Its historical symbol was a star over Fortune's wheel; it was encoded in Unicode 17.0 as U+1CECC 𜻌 (12px).[10][11]

Physical characteristics

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. Fortuna has been studied by radar.[12]

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.[6] A more recent estimate by Baer suggests it has a mass of 1.27×1019 kg.[3]

On 21 December 2012, Fortuna (~200 km) harmlessly passed within 6.5 Gm of asteroid 687 Tinette.[13]

Notes

  1. ↑ Flattening derived from the maximum aspect ratio (c/a): f=1−ca, where (c/a) = 0.79±0.05.[4]

References

  1. ↑ Noah Webster (1884) A Practical Dictionary of the English Language
  2. ↑ 2.0 2.1 2.2 2.3 2.4 "JPL Small-Body Database Browser: 19 Fortuna". http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=19. Retrieved 2024-12-21. 
  3. ↑ 3.0 3.1 3.2 3.3 Jim Baer (2008). "Recent Asteroid Mass Determinations". Personal Website. http://home.earthlink.net/~jimbaer1/astmass.txt. Retrieved 2008-11-27. 
  4. ↑ 4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 4.10 P. Vernazza et al. (2021) VLT/SPHERE imaging survey of the largest main-belt asteroids: Final results and synthesis. Astronomy & Astrophysics 54, A56
  5. ↑ Storrs, AlexExpression error: Unrecognized word "etal". (1998). "Imaging Observations of Asteroids with Hubble Space Telescope". Icarus 137 (2): 260–268. doi:10.1006/icar.1999.6047. Bibcode: 1999Icar..137..260S. Archived from the original on 25 February 2012. https://web.archive.org/web/20120225134811/http://scripts.mit.edu/~paleomag/articles/Storrs_1999_Icarus.pdf. Retrieved 2005-01-15. 
  6. ↑ 6.0 6.1 "Astrometric masses of 21 asteroids, and an integrated asteroid ephemeris". Celestial Mechanics and Dynamical Astronomy (Springer Science+Business Media B.V. 2007) 100 (2008): 27–42. 2008. doi:10.1007/s10569-007-9103-8. Bibcode: 2008CeMDA.100...27B. 
  7. ↑ "AstDys (19) Fortuna Ephemerides". Department of Mathematics, University of Pisa, Italy. https://newton.spacedys.com/astdys/index.php?pc=1.1.3.1&n=19&oc=500&y0=1963&m0=10&d0=31&h0=0&mi0=0&y1=1963&m1=10&d1=31&h1=0&mi1=0&ti=1.0&tiu=days. Retrieved 2010-06-27. 
  8. ↑ Storrs, Alex 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. Bibcode: 2005Icar..173..409S. Archived from the original on April 18, 2007. https://web.archive.org/web/20070418034343/http://web.mit.edu/bpweiss/www/StorrsWeiss2005AsteroidsHSTIcarus.pdf. Retrieved 2007-09-23. 
  9. ↑ Fornasier, S. et al. (February 1999), "Spectroscopic comparison of aqueous altered asteroids with CM2 carbonaceous chondrite meteorites", Astronomy and Astrophysics Supplement 135: 65–73, doi:10.1051/aas:1999161, Bibcode: 1999A&AS..135...65F, https://ui.adsabs.harvard.edu/link_gateway/1999A&AS..135...65F/PUB_PDF. 
  10. ↑ 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. 
  11. ↑ "Miscellaneous Symbols Supplement". The Unicode Consortium. 2025. https://www.unicode.org/charts/PDF/U1CEC0.pdf. 
  12. ↑ "Radar-Detected Asteroids and Comets". NASA/JPL Asteroid Radar Research. http://echo.jpl.nasa.gov/asteroids/. Retrieved 2011-10-30. 
  13. ↑ Generated with Solex 10 by Aldo Vitagliano



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