4 Vesta

4 Vesta

4 Vesta seen by Dawn spacecraft July 9, 2011
Discovery
Discovered by	Heinrich Wilhelm Olbers
Discovery date	March 29, 1807
Designations
Alternative names	none
Minor planet category	Main belt (Vesta family)
Orbital characteristics
Epoch November 26, 2005 (JD 2453700.5)
Aphelion	384.72 Gm (2.572 AU)
Perihelion	321.82 Gm (2.151 AU)
Semi-major axis	353.268 G m (2.361 AU)
Eccentricity	0.08902
Orbital period	1325.46 d (3.63 a)
Average orbital speed	19.34 km/s
Mean anomaly	205.652°
Inclination	7.133°
Longitude of ascending node	103.926°
Argument of perihelion	150.297°
Physical characteristics
Dimensions	578×560×458 km[1]
Mass	2.7×1020 kg[2]
Mean density	3.4 g/cm³
Surface gravity	0.22 m/s²
Escape velocity	0.35 km/s
Rotation period	0.2226 d[3]
Albedo	0.423 (geometric)[4]
Temperature	min: 85 K (-188° C) max: 255 K (-18 °C)[5]
Spectral type	V-type asteroid[6]
Apparent magnitude	5.1[7] to 8.48
Absolute magnitude (H)	3.20[4]
Angular diameter	0.64" to 0.20"

4 Vesta (IPA: [ˈvɛstə]) is the second most massive asteroid in the solar system, with an average diameter of about 530 km (around 330 miles) and an estimated mass of 9% of the mass of the entire asteroid belt. Its size and unusually bright surface makes Vesta the brightest asteroid, and the only one ever visible to the naked eye from Earth. Vesta's astronomical symbol is .

1. ↑ P. C. Thomas et al. Impact excavation on asteroid 4 Vesta: Hubble Space Telescope results, Science, Vol. 277, pp. 1492 (1997).
2. ↑ Pitjeva, E. V. (2004). "Estimations of masses of the largest asteroids and the main asteroid belt from ranging to planets, Mars orbiters and landers". 35th COSPAR Scientific Assembly. Held 18 - July 25, 2004, in Paris, France. Vol. 35. p. 2014. Bibcode:2004cosp...35.2014P.
3. ↑ Harris, A. W. (2006). "Asteroid Lightcurve Derived Data. EAR-A-5-DDR-DERIVED-LIGHTCURVE-V8.0". Warner, B.D.; Pravec, P.; Eds. NASA Planetary Data System. Retrieved March 15, 2007.
4. ↑ ^{4.0 4.1} Tedesco, E.F. (2004). "IRAS Minor Planet Survey. IRAS-A-FPA-3-RDR-IMPS-V6.0". Noah, P.V.; Noah, M.; Price, S.D. NASA Planetary Data System. Retrieved March 15, 2007.
5. ↑ T. G. Mueller and L. Metcalfe ISO and Asteroids^{[permanent dead link]}, ESA bulletin Vol. 108, p. 38 (2001).
6. ↑ Neese, C., ed. (2005). "Asteroid Taxonomy.EAR-A-5-DDR-TAXONOMY-V5.0". NASA Planetary Data System. Retrieved March 15, 2007.
7. ↑ Donald H. Menzel and Jay M. Pasachoff (1983). A Field Guide to the Stars and Planets (2nd ed.). Boston, MA: Houghton Mifflin. p. 391. ISBN 0-395-34835-8.