932 Hooveria

932 Hooveria (prov. designation: A920 FC or 1920 GV) is a dark background asteroid, approximately 59 kilometers (37 miles) in diameter, located in the inner region of the asteroid belt. It was discovered by Austrian astronomer Johann Palisa at the Vienna Observatory on 23 March 1920.^[1] The carbonaceous C-type asteroid (Ch) has a long rotation period of 78.4 hours. It was named after then-Secretary of Commerce Herbert Hoover (1874–1964), who later became president of the United States.^[2]

932 Hooveria

Discovery[1]
Discovered by	J. Palisa
Discovery site	Vienna Obs.
Discovery date	23 March 1920
Designations
MPC designation	(932) Hooveria
Named after	Herbert Hoover (U.S. Secretary of Commerce)[2]
Alternative designations	A920 FC · 1920 GV A909 GG · 1909 GG A912 BD · 1912 BD A913 MD · 1913 MD A914 TF · 1914 TF 1950 HQ
Minor planet category	main-belt[1][3] · (inner) background[4][5]
Orbital characteristics[3]
Epoch 31 May 2020 (JD 2459000.5)
Uncertainty parameter 0
Observation arc	99.79 yr (36,448 d)
Aphelion	2.6386 AU
Perihelion	2.2002 AU
Semi-major axis	2.4194 AU
Eccentricity	0.0906
Orbital period (sidereal)	3.76 yr (1,375 d)
Mean anomaly	331.44°
Mean motion	0° 15m 42.84s / day
Inclination	8.1137°
Longitude of ascending node	14.956°
Argument of perihelion	50.025°
Physical characteristics
Mean diameter	58.978±0.804 km[6] 60.20±0.71 km[7]
Synodic rotation period	78.44±0.01 h[8][9]
Geometric albedo	0.049±0.001[7] 0.051±0.006[6]
Spectral type	Tholen = CB[3] Caa (S3OS2-TH)[10] Ch (S3OS2-BB)[10] B–V = 0.673±0.018[3] U–B = 0.328±0.040[3]
Absolute magnitude (H)	10.00[3] 10.1[1]

Orbit and classification

Hooveria is a non-family asteroid of the main belt's background population when applying the hierarchical clustering method to its proper orbital elements.^[4][5] It orbits the Sun in the inner asteroid belt at a distance of 2.2–2.6 AU once every 3 years and 9 months (1,375 days; semi-major axis of 2.42 AU). Its orbit has an eccentricity of 0.09 and an inclination of 8° with respect to the ecliptic.^[3] The asteroid was first observed as A909 GG (1909 GG) at Heidelberg Observatory on 16 April 1909. The body's observation arc begins with its official discovery observation at Vienna Observatory on 23 March 1920.^[1]

Naming

This minor planet was named by the Academic Senate of the Vienna University in honor of then-Secretary of Commerce Herbert Hoover (1874–1964), in recognition of his help to Austria after World War I. The naming was mentioned in the Astronomische Nachrichten in 1922 (AN 216, 192).^[2] Hoover became the 31st president of the United States from 1929 to 1933. A second asteroid 1363 Herberta was also named after him in 1938.

Another of Palisa's discoveries, asteroid 941 Murray, was also named in appreciation for the help provided to post-war Austria. In this case, it was named after British classical scholar and diplomat Gilbert Murray (1866–1957).

Physical characteristics

In the Tholen classification, Hooveria is classified as a CB-asteroid, closest to a carbonaceous C-type and somewhat similar to a brighter B-type asteroid.^[3] In the Small Solar System Objects Spectroscopic Survey (S3OS2), the asteroid is a Caa-type in the survey's Tholen-like taxonomy, and a hydrated Ch-subtype in the SMASS-like taxonomy of the S3OS2.^[5][10]

Rotation period

In December 2016, a rotational lightcurve of Hooveria was obtained from photometric observations by Anna Marciniak at the Poznań Observatory and other observers around the world during a survey, that collected spin and shape properties of long-period main-belt asteroids. Lightcurve analysis gave a well-defined rotation period of 78.44±0.01 hours with a brightness variation of 0.24±0.02 magnitude (U=3).^[8] The results supersede observations by Brian Warner at the Palmer Divide Observatory (716) and collaborators from February 2010, which gave a rotation period 39.1±0.1 hours (or half the period solution) with a brightness amplitude of 0.22±0.02 magnitude (U=2+).^[11][a]

Diameter and albedo

According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer (WISE) and the Japanese Akari satellite, Hooveria measures (58.978±0.804) and (60.20±0.71) kilometers in diameter and its surface has an albedo of (0.051±0.006) and (0.049±0.001), respectively.^[6][7] The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.20 and calculates a diameter of 29.72 km based on an absolute magnitude of 10.00.^[9]

Further published mean-diameters and albedos by the WISE team include (59.101±21.01 km), (60.54±17.87 km), (61.70±21.32 km) and (62.973±1.412 km) with corresponding albedos of (0.0347±0.0290), (0.04±0.08), (0.03±0.02), and (0.0296±0.0039).^[5][9] An asteroid occultation on 1 February 2006, gave a best-fit ellipse dimension of 33.0 × 33.0 kilometers.^[5] These timed observations are taken when the asteroid passes in front of a distant star. However the quality of the measurement is poorly rated.^[5]

Notes

1. Lightcurve plot of (932) Hooveria, Palmer Divide Observatory, Brian Warner (2010). Rotation period 39.1±0.1 hours with a brightness amplitude of 0.22±0.02 mag. Quality code of 2+. Summary figures for (932) Hooveria at the LCDB