4185 Phystech

4185 Phystech, provisional designation 1975 ED, is a Florian or background asteroid from the inner regions of the asteroid belt, approximately 6 kilometers (4 miles) in diameter. It was discovered on 4 March 1975, by Soviet astronomer Tamara Smirnova at the Crimean Astrophysical Observatory in Nauchnij, on the Crimean peninsula.^[1] The presumed S-type asteroid has a rotation period of 4.67 hours. It is named in honor of the Moscow Institute of Physics and Technology ("PhysTech") on its 50th anniversary.^[1]

4185 Phystech

Discovery[1]
Discovered by	T. Smirnova
Discovery site	Crimean Astrophysical Obs.
Discovery date	4 March 1975
Designations
MPC designation	(4185) Phystech
Named after	Moscow Institute of Physics and Technology[1]
Alternative designations	1975 ED · 1982 KD 1982 KH4 · 1988 BT
Minor planet category	main-belt[1][2] · (inner) background[3][4] · Flora[5]
Orbital characteristics[2]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc	64.48 yr (23,550 d)
Aphelion	2.4339 AU
Perihelion	2.0008 AU
Semi-major axis	2.2174 AU
Eccentricity	0.0977
Orbital period (sidereal)	3.30 yr (1,206 d)
Mean anomaly	311.69°
Mean motion	0° 17m 54.6s / day
Inclination	2.2303°
Longitude of ascending node	265.78°
Argument of perihelion	320.99°
Physical characteristics
Mean diameter	5.93 km (calculated)[5]
Synodic rotation period	4.66883±0.00014 h[6] 4.66904±0.00003 h[6]
Geometric albedo	0.24 (assumed)[5]
Spectral type	S (assumed)[5]
Absolute magnitude (H)	13.3[2][5]

Orbit and classification

Phystech is a non-family asteroid of the main belt's background population when applying the hierarchical clustering method to its proper orbital elements.^[3][4] Based on osculating Keplerian orbital elements, the asteroid has also been classified as a member of the Flora family (402), a giant asteroid family and the largest family of stony asteroids in the main-belt.^[5]

It orbits the Sun in the inner asteroid belt at a distance of 2.0–2.4 AU once every 3 years and 4 months (1,206 days; semi-major axis of 2.22 AU). Its orbit has an eccentricity of 0.10 and an inclination of 2° with respect to the ecliptic.^[2] The body's observation arc begins with a precovery taken at Palomar Observatory in October 1953, more than 21 years prior to its official discovery observation at Nauchnij.^[1]

Physical characteristics

Phystech is an assumed stony S-type asteroid, based on its family classification.^[5]

Rotation period

In March and April 2008, two rotational lightcurves of Phystech were obtained from photometric observations by American astronomers at LPL and Calvin College (H62). Lightcurve analysis gave a well-defined rotation period of 4.66883 and 4.66904 hours with a brightness amplitude of 0.53 and 0.41 magnitude, respectively (U=3/3).^[6]

Diameter and albedo

The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.24 – derived from 8 Flora, the parent body of the Flora family – and calculates a diameter of 5.93 kilometers based on an absolute magnitude of 13.3.^[5]

Naming

This minor planet was named after the Moscow Institute of Physics and Technology (informally: "PhysTech"; Физтех) on the occasion of its 50th anniversary in 1996, based on a proposal by the Institute of Theoretical Astronomy (ITA) in Saint Petersburg, Russia.^[1] The official naming citation was published by the Minor Planet Center on 22 February 1997 (M.P.C. 29143).^[7]