4962 Vecherka

4962 Vecherka, provisional designation 1973 TP, is a Eunomian asteroid and slow rotator from the central regions of the asteroid belt, approximately 10 kilometers in diameter. It was discovered on 1 October 1973, by Soviet astronomer Tamara Smirnova at the Crimean Astrophysical Observatory in Nauchnij, on the Crimean peninsula.^[12] The asteroid was named after Vechernij Petersburg, a newspaper that also publishes astronomical information.^[2]

4962 Vecherka

Discovery[1]
Discovered by	T. Smirnova
Discovery site	Crimean Astrophysical Obs.
Discovery date	1 October 1973
Designations
MPC designation	(4962) Vecherka
Named after	Vechernij Petersburg[2] (Russian newspaper)
Alternative designations	1973 TP · 1952 TF 1969 TM6 · 1973 UG3 1986 WC3
Minor planet category	main-belt · (middle) Maria[3] · background[4]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc	64.61 yr (23,600 days)
Aphelion	2.9857 AU
Perihelion	2.2265 AU
Semi-major axis	2.6061 AU
Eccentricity	0.1457
Orbital period (sidereal)	4.21 yr (1,537 days)
Mean anomaly	170.48°
Mean motion	0° 14m 3.48s / day
Inclination	15.108°
Longitude of ascending node	207.02°
Argument of perihelion	141.66°
Physical characteristics
Dimensions	8.54±0.59 km[5] 9.62±2.43 km[6] 9.951±0.201 km[7][8] 10.06 km (calculated)[9]
Synodic rotation period	336±48 h[10]
Geometric albedo	0.21 (assumed)[9] 0.210±0.038[7] 0.21±0.11[6] 0.2102±0.0377[8] 0.349±0.170[5]
Spectral type	S (assumed)[9]
Absolute magnitude (H)	11.94±0.27[11] · 12.10[5][8] · 12.3[1][9] · 12.67[6]

Orbit and classification

When applying the hierarchical clustering method to its proper orbital elements, Vecherka has both been considered a non-family asteroid of the main belt's background population (according to Nesvorný),^[4] and core member of the Maria family (according to Milani and Knežević).^[3]

It orbits the Sun in the central asteroid belt at a distance of 2.2–3.0 AU once every 4 years and 3 months (1,537 days). Its orbit has an eccentricity of 0.15 and an inclination of 15° with respect to the ecliptic.^[1] The body's observation arc begins with its first observation as 1952 TF at Uccle Observatory in October 1952, or 21 years prior to its official discovery observation at Nauchnij.^[12]

Physical characteristics

Vecherka is an assumed stony S-type asteroid,^[9] which corresponds to the overall spectral type of the Maria family.^[13]: 23

Slow rotator

In August 2015, a rotational lightcurve of Vecherka was obtained from photometric observations by a collaboration of Bulgarian astronomers. Lightcurve analysis gave a long rotation period of 336±48 hours with a brightness variation of 1.08 magnitude (U=2), indicating that the body's shape is irregular and elongated rather than spherical.^[10] This long period makes Vecherka a slow rotator, which ranks among the Top 200 slowest ones known to exists.

Diameter and albedo

According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Vecherka measures between 8.54 and 9.951 kilometers in diameter and its surface has an albedo between 0.210 and 0.349.^[5][6][7][8]

The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.21 – derived from 15 Eunomia, the family's largest member and namesake – and calculates a diameter of 10.06 kilometers based on an absolute magnitude of 12.3.^[9]

Naming

Based on a proposal by the Institute of Theoretical Astronomy (ITA), this minor planet was named after Vechernij Petersburg, a popular evening newspaper from Saint Petersburg, Russia, that publishes astronomical information and articles popularizing astronomical knowledge on a regular basis.^[2] The official naming citation was published by the Minor Planet Center on 14 December 1997 (M.P.C. 31023).^[14]