10 Hygiea

Discovery A
Discoverer	A. de Gasparis
Discovery date	April 12, 1849
Alternate designations	none B
Category	Main belt (Hygiea family)
Orbital elements C D
Epoch July 14, 2004 (JD 2453200.5)
Eccentricity (e)	0.119
Semi-major axis (a)	469.345 Gm (3.137 AU)
Perihelion (q)	413.378 Gm (2.763 AU)
Aphelion (Q)	525.311 Gm (3.511 AU)
Orbital period (P)	2029.776 d (5.56 a)
Mean orbital speed	16.82 km/s
Inclination (i)	3.842°
Longitude of the ascending node (Ω))	283.646°
Argument of perihelion (ω)	313.557°
Mean anomaly (M)	273.788°
Physical characteristics
Dimensions	407.1 km
Mass	1.0—1020 kg
Density	2.76 g/cm³ 1
Surface gravity	0.1603 m/s²
Escape velocity	0.2554 km/s
Rotation period	1.1510 d 2
Spectral class	C-type asteroid
Absolute magnitude	5.43
Albedo	0.072 3
Mean surface temperature	~158 K

10 Hygiea (hye-jee'-a or hi-jee'-a) is the fourth largest main belt asteroid with a diameter of 407 km. The dark-coloured surface makes the asteroid dimmer than the size would imply. Hygiea is composed of primitive carbonaceous material similar to the chondrite meteorites. It is the main member of the Hygiea family.

Hygiea was discovered by A. de Gasparis on April 12, 1849 in Naples, Italy. It was his first of many asteroid discoveries. It is named after Hygieia, the greek goddess of health, daughter of Asclepius (Aesculapius for the Romans). De Gasparis let his friend Ernesto Capocci name the asteroid to thank him for his encouragement.

The Hubble Space Telescope was able to resolve the spherical shape of the asteroid. So far there are 5 observed stellar occultations by 10 Hygiea.

Aspects

Stationary, retrograd	Opposition	distance to earth (AU)	maximum brightness	Stationär, prograde	conjunction to sun
February 5, 2005	March 26, 2005	1.88360	9.3 mag	May 13, 2005	November 21, 2005
May 23, 2006	July 12, 2006	1.86527	9.2 mag	August 31, 2006	February 22, 2007
August 8, 2007	October 4, 2007	2.36399	10.1 mag	November 23, 2007	May 1, 2008
October 9, 2008	December 3, 2008	2.51309	10.3 mag	January 26, 2009	July 4, 2009
December 16, 2009	February 6, 2010	2.16963	9.8 mag	March 31, 2010	September 24, 2010
March 27, 2011	May 13, 2011	1.75632	9.1 mag	June 28, 2011	January 5, 2012
June 29, 2012	August 22, 2012	2.09214	9.7 mag	October 11, 2012	March 26, 2013
September 5, 2013	October 31, 2013	2.49363	10.3 mag	December 22, 2013	May 29, 2014
November 7, 2014	December 31, 2014	2.41334	10.1 mag	February 23, 2015	August 6, 2015
January 25, 2016	March 15, 2016	1.93746	9.4 mag	May 3, 2016	November 8, 2016
May 13, 2017	June 30, 2017	1.82025	9.0 mag	August 18, 2017	February 13, 2018
July 31, 2018	September 25, 2018	2.31617	10.1 mag	November 15, 2018	April 24, 2019
October 3, 2019	November 27, 2019	2.52255	10.3 mag	January 20, 2020	June 26, 2020
December 7, 2020	January 29, 2021	2.22744	9.8 mag	March 23, 2021	September 13, 2021

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