17 Thetis

**17 Thetis**
Discovery ^A

Discoverer	R. Luther
Discovery date	April 17, 1852
Alternate designations ^B	A913 CA; A916 YF; 1954 SO₁
Category	Main belt
Orbital elements ^C
Epoch October 22, 2004 (JD 2453300.5)
Eccentricity (e)	0.134
Semi-major axis (a)	369.530 G m (2.470 AU)
Perihelion (q)	319.991 Gm (2.139 AU)
Aphelion (Q)	419.069 Gm (2.801 AU)
Orbital period (P)	1418.027 d (3.88 a)
Mean orbital speed	18.87 km/s
Inclination (i)	5.587°
Longitude of the ascending node (Ω)	125.622°
Argument of perihelion (ω)	135.906°
Mean anomaly (M)	38.435°
Physical characteristics ^D
Dimensions	90 km
Mass	7.6×10¹⁷ kg
Density	2.0? g/cm³
Surface gravity	0.0252 m/s²
Escape velocity	0.0476 km/s
Rotation period	0.5113 d (12.27 h) ¹
Spectral class	S
Absolute magnitude	7.76
Albedo (geometric)	0.1715 ²
Mean surface temperature	~173 K
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17 Thetis (thee'-təs (key)) is a large Main belt asteroid. It is a S-type asteroid, so it has a relatively bright silicate surface.

It was discovered by R. Luther on April 17, 1852. It was his first asteroid discovery. Its name comes from Thetis, the mother of Achilles in Greek mythology.

One Thetidian stellar occultation was observed from Oregon in 1999. However, the event was not timed.

[edit] Aspects

Stationary, retrograde	Opposition	Distance to Earth (AU)	Maximum brightness (mag)	Stationary, prograde	Conjunction to Sun
May 13, 2004	June 23, 2004	1.12505	10.0	August 4, 2004	March 12, 2005
September 20, 2005	November 9, 2005	1.74593	11.5	December 31, 2005	June 23, 2006
December 24, 2006	February 8, 2007	1.61890	11.0	March 30, 2007	October 19, 2007
June 4, 2008	July 17, 2008	1.15973	9.9	August 26, 2008	March 26, 2009
October 1, 2009	November 20, 2009	1.78755	11.5	January 11, 2010	July 5, 2010
January 8, 2011	February 21, 2011	1.53906	10.9	April 11, 2011	November 8, 2011
June 25, 2012	August 7, 2012	1.22746	10.1	September 18, 2012	April 9, 2013
October 11, 2013	December 1, 2013	1.81341	11.6	January 22, 2014	July 17, 2014
January 24, 2015	March 8, 2015	1.45107	10.8	April 26, 2015	November 30, 2015
July 14, 2016	August 26, 2015	1.31557	10.4	October 9, 2016	April 22, 2017
October 21, 2017	December 12, 2017	1.82324	11.6	February 1, 2018	July 29, 2018
February 11, 2019	March 24, 2019	1.35935	10.6	May 11, 2019	December 22, 2018
July 30, 2020	September 12, 2020	1.41160	10.7	October 20, 2020	May 5, 2021

Minor planets
Previous minor planet	17 Thetis	Next minor planet

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