1425 Tuorla

1425 Tuorla, provisional designation 1937 GB, is a stony Eunomian asteroid from the central regions of the asteroid belt, approximately 14 kilometers in diameter. It was discovered on 3 April 1937, by Finnish astronomer Kustaa Inkeri at the Iso-Heikkilä Observatory in Turku, southwestern Finland.^[12] The asteroid was named after the Tuorla Observatory of the University of Turku.^[2] It was Kustaa Inkeri's only asteroid discovery.^[13]

1425 Tuorla

Discovery[1]
Discovered by	K. Inkeri
Discovery site	Turku Obs.
Discovery date	3 April 1937
Designations
MPC designation	(1425) Tuorla
Named after	Tuorla Observatory[2] (Inst. for Astronomy and Optics)
Alternative designations	1937 GB · 1950 KC 1950 LQ
Minor planet category	main-belt · (middle) Eunomia[3][4]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc	67.14 yr (24,522 days)
Aphelion	2.8766 AU
Perihelion	2.3483 AU
Semi-major axis	2.6125 AU
Eccentricity	0.1011
Orbital period (sidereal)	4.22 yr (1,542 days)
Mean anomaly	40.218°
Mean motion	0° 14m 0.24s / day
Inclination	12.975°
Longitude of ascending node	185.99°
Argument of perihelion	342.25°
Physical characteristics
Dimensions	11.795±0.874 km[5] 14.34±1.08 km[6] 14.94±1.1 km[3][7]
Synodic rotation period	6.76±0.01 h[a] 6.97±0.01 h[8] 7.748±0.0027 h[9] 7.75±0.06 h[10]
Geometric albedo	0.2389 (derived)[3] 0.2390±0.040[7] 0.260±0.041[6] 0.383±0.083[5]
Spectral type	S[3][11]
Absolute magnitude (H)	11.173±0.003 (R)[9] · 11.30[3][5][6][7] · 11.4[1] · 11.91±0.41[11]

Orbit and classification

Tuorla is a member of the Eunomia family (502),^[3][4] a prominent family of stony asteroids and the largest one in the intermediate main belt with more than 5,000 members.^[14]: 23 It orbits the Sun at a distance of 2.3–2.9 AU once every 4 years and 3 months (1,542 days). Its orbit has an eccentricity of 0.10 and an inclination of 13° with respect to the ecliptic.^[1] The body's observation arc begins at Turku, the night before its official discovery observation.^[12]

Physical characteristics

Tuorla has been characterized as a stony S-type asteroid by Pan-STARRS photometric survey,^[11] in accordance with the overall spectral type for members of the Eunomia family.^[14]: 23

Rotation period

In April 2013, the so-far best-rated a rotational lightcurve of Tuorla was obtained from photometric observations by astronomer Vladimir Benishek at Belgrade Observatory in Serbia. Lightcurve analysis gave a well-defined rotation period of 7.75 hours (h) with a brightness variation of 0.24 magnitude (U=3).^[10] Other lightcurves were obtained by Alfonso Carreno Garceran (6.76 h),^[a] Laurent Bernasconi (7.75 h),^[8] and the Palomar Transient Factory (7.748 h),^[9]

Diameter and albedo

According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Tuorla measures between 11.795 and 14.94 kilometers in diameter and its surface has an albedo between 0.2390 and 0.383.^[5][6][7] The Collaborative Asteroid Lightcurve Link derives an albedo of 0.2389 and adopts a diameter of 14.94 kilometers from IRAS, based on an absolute magnitude of 11.3.^[3]

Naming

This minor planet was named after the Tuorla Observatory, the Research Institute for Astronomy and Optics, of the University of Turku, located in Piikkiö near Turku, Finland.^[2] The Tuorla Observatory was established by prolific minor-planet discoverer Yrjö Väisälä in 1952, as an alternative to the Iso-Heikkilä Observatory, where this asteroid was discovered. The official naming citation was published by the Minor Planet Center on 30 January 1964 (M.P.C. 2277).^[15]

Notes

1. Garceran (2013) web: rotation period hours with a brightness amplitude of mag. Summary figures for (1425) Tuorla at LCDB