189 Phthia

189 Phthia is a bright-coloured, rocky main belt asteroid that was discovered by German-American astronomer Christian Heinrich Friedrich Peters on September 9, 1878,^[1] in Clinton, New York, and named after Phthia, a region of ancient Greece.

DiscoveredbyC. H. F. Peters

DiscoverysiteClinton, New York

Discoverydate9 September 1878

MPCdesignation

(189) Phthia

Quick facts Discovery, Discovered by ...

189 Phthia

3D convex shape model of 189 Phthia
Discovery[1]
Discovered by	C. H. F. Peters
Discovery site	Clinton, New York
Discovery date	9 September 1878
Designations
MPC designation	(189) Phthia
Pronunciation	/ˈθaɪ.ə/[2]
Alternative designations	A878 RA
Minor planet category	main-belt
Orbital characteristics[3][4]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc	136.18 yr (49739 d)
Aphelion	2.5415 AU (380.20 Gm)
Perihelion	2.3597 AU (353.01 Gm)
Semi-major axis	2.4506 AU (366.60 Gm)
Eccentricity	0.037105
Orbital period (sidereal)	3.84 yr (1401.2 d)
Mean anomaly	336.98°
Mean motion	0° 15m 24.912s / day
Inclination	5.1774°
Longitude of ascending node	203.42°
Argument of perihelion	168.03°
Physical characteristics
Dimensions	37.66±2.0 km[3] 40.91 ± 1.36 km[5]
Mass	(3.84 ± 0.81) × 1016 kg[5]
Mean density	1.07 ± 0.25 g/cm3[5]
Synodic rotation period	22.346 h (0.9311 d)[3][6]
Geometric albedo	0.2310±0.027[3] 0.1566 ± 0.0349[7]
Spectral type	S[7] (Tholen)
Absolute magnitude (H)	9.33,[3] 9.60[7]

Close

Photometric observations of this asteroid at the Organ Mesa Observatory in Las Cruces, New Mexico, during 2008 gave a light curve with a period of 22.346 ± 0.001 hours and a brightness variation of 0.26 ± 0.02 in magnitude.^[6]