197 Arete

197 Arete is an asteroid in the asteroid belt. It has a very bright surface, even so when compared to other rocky S-type asteroid.

DiscoveredbyJohann Palisa

Discoverydate21 May 1879

MPCdesignation

(197) Arete

Pronunciation/əˈriːtiː/^[2]

Quick facts Discovery, Discovered by ...

197 Arete

Orbital diagram
Discovery[1]
Discovered by	Johann Palisa
Discovery date	21 May 1879
Designations
MPC designation	(197) Arete
Pronunciation	/əˈriːtiː/[2]
Named after	Arete
Alternative designations	A879 KA; 1934 RE1; 1950 DY
Minor planet category	Asteroid belt
Orbital characteristics[3][4]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc	136.89 yr (50000 d)
Aphelion	3.1882283 AU (476.95216 Gm) (Q)
Perihelion	2.2897600 AU (342.54322 Gm) (q)
Semi-major axis	2.7389941 AU (409.74769 Gm) (a)
Eccentricity	0.1640143 (e)
Orbital period (sidereal)	4.53 yr (1655.7 d)
Mean anomaly	20.361539° (M)
Mean motion	0° 13m 2.744s / day (n)
Inclination	8.793773° (i)
Longitude of ascending node	81.607160° (Ω)
Argument of perihelion	246.46589° (ω)
Earth MOID	1.29448 AU (193.651 Gm)
Jupiter MOID	2.16829 AU (324.372 Gm)
TJupiter	3.314
Physical characteristics[5]
Dimensions	29.18±2.4 km
Synodic rotation period	6.6084 h (0.27535 d)[3] 6.54 h[6]
Geometric albedo	0.4417±0.083[3] 0.442[7]
Spectral type	S[8]
Absolute magnitude (H)	9.18[3]

Close

It was discovered by J. Palisa on May 21, 1879, and named after Arete, the mother of Nausicaa in Homer's The Odyssey.^[9] Every 18 years, this asteroid approaches within 0.04 AU of 4 Vesta. During these encounters, Vesta causes a gravitational perturbation of Arete, allowing the mass of Vesta to be directly determined.^[10]

Photometric observations during 1984 showed a rotation period of 6.54 ± 0.02 hours and a brightness variation of 0.10 ± 0.01 in magnitude. The light curve shows "four well defined extrema with two asymmetric maxima".^[11]