1527 Malmquista

For other uses of Malmquist, see Malmquist (disambiguation).

1527 Malmquista, provisional designation 1939 UG, is a stony Florian asteroid from the inner regions of the asteroid belt, approximately 10 kilometers in diameter.

1527 Malmquista

Lightcurve-based 3D-model of Malmquista
Discovery[1]
Discovered by	Y. Väisälä
Discovery site	Turku Obs.
Discovery date	18 October 1939
Designations
MPC designation	(1527) Malmquista
Named after	Gunnar Malmquist (astronomer)[2]
Alternative designations	1939 UG · 1929 TG 1932 OB · 1972 TK A909 TC
Minor planet category	main-belt · Flora[3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc	87.47 yr (31,948 days)
Aphelion	2.6694 AU
Perihelion	1.7846 AU
Semi-major axis	2.2270 AU
Eccentricity	0.1987
Orbital period (sidereal)	3.32 yr (1,214 days)
Mean anomaly	203.99°
Mean motion	0° 17m 47.76s / day
Inclination	5.1939°
Longitude of ascending node	16.133°
Argument of perihelion	304.49°
Physical characteristics
Dimensions	9.55±0.49 km[4] 10.040±0.134 km[5] 10.338±0.071 km[6] 10.80 km (calculated)[3]
Synodic rotation period	14.044±0.0244 h[7] 14.0591 h[8] 14.077±0.004 h[9]
Geometric albedo	0.2202±0.0169[6] 0.24 (assumed)[3] 0.307±0.037[4]
Spectral type	S[3]
Absolute magnitude (H)	12.0[1][3][4] · 12.2[6] · 12.481±0.002 (S)[7]

It was discovered on 18 October 1939, by Finnish astronomer Yrjö Väisälä at Turku Observatory in Southwest Finland.^[10] It was named for the Swedish astronomer Gunnar Malmquist.^[2]

Orbit and classification

Malmquista is a member of the Flora family, one of the largest families of stony asteroids in the main belt. It orbits the Sun in the inner main-belt at a distance of 1.8–2.7 AU once every 3 years and 4 months (1,214 days). Its orbit has an eccentricity of 0.20 and an inclination of 5° with respect to the ecliptic.^[1] In 1909, it was first observed at Heidelberg Observatory as A909 TC. The body's observation arc begins at Lowell Observatory in 1929, when it was identified as 1929 TG, 10 years prior to its official discovery observation at Turku.^[10]

Physical characteristics

Rotation period

In September 2002, a first rotational lightcurve of Malmquista was obtained from photometric observations by Stephen Brincat at Flarestar Observatory on the island of Malta. Lightcurve analysis gave a well-defined rotation period of 14.077 hours with a brightness variation of 0.60 magnitude (U=3).^[9] In September 2012, observations at the Palomar Transient Factory, California, gave a period of 14.044 hours and an amplitude of 0.42 magnitude (U=2).^[7]

Spin axis

In 2013, an international study modeled a lightcurve with a period of 14.0591 hours and found a spin axis of (5.0°, 80.0°) in ecliptic coordinates (λ, β) (U=n.a.).^[8]

Diameter and albedo

According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Malmquista measures between 9.55 and 10.338 kilometers in diameter and its surface has an albedo between 0.220 and 0.307.^[4][5][6] The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.24 – derived from 8 Flora, a S-type asteroid and the family's largest member and namesake – and calculates a diameter of 10.80 kilometers with an absolute magnitude of 12.0.^[3]

Naming

This minor planet was named after Swedish astronomer Gunnar Malmquist (1893–1982), director of the Uppsala Astronomical Observatory in Sweden.^[2] The official naming citation was published by the Minor Planet Center in January 1956 (M.P.C. 1350).^[11]