1082 Pirola

Modelled shape of Pirola from its lightcurve
Discovery [1]
Discovered by	K. Reinmuth
Discovery site	Heidelberg Obs.
Discovery date	28 October 1927
Designations
MPC designation	(1082) Pirola
Pronunciation	/ˈpɪrələ/ [2]
Named after	Pyrola ( wintergreen) ( herbaceous plant) [3]
Alternative designations	1927 UC · 1931 JQ 1951 AH · 1952 DS 1971 YJ · A916 UP
Minor planet category	main-belt [1] [4] · ( outer) Themis [5] [6] [7]
Orbital characteristics [4]
Epoch 4 September 2017 ( JD 2458000.5)
Uncertainty parameter 0
Observation arc	90.01 yr (32,875 days)
Aphelion	3.6858 AU
Perihelion	2.5553 AU
Semi-major axis	3.1205 AU
Eccentricity	0.1811
Orbital period (sidereal)	5.51 yr (2,013 days)
Mean anomaly	130.74 °
Mean motion	0° 10m 43.68s / day
Inclination	1.8524°
Longitude of ascending node	148.01°
Argument of perihelion	187.23°
Physical characteristics
Mean diameter	37.363±1.036 km [8] 39.14±13.91 km [9] 41.47±12.07 km [10] 42.607±0.476 km [11] 42.61±0.48 km [11] 44.67±0.71 km [12]
Synodic rotation period	15.85±0.01  h [13] 15.851±0.0140 h [14] 15.8525±0.0005 h [15] 15.8540±0.0001 h [16]
Pole ecliptic latitude	(123.0°, −42.0°) (λ1/β1) [6] (300.0°, −38.0°) (λ2/β2) [6]
Geometric albedo	0.052±0.006 [17] 0.06±0.05 [9] [10] 0.061±0.002 [12] 0.067±0.008 [11] 0.0867±0.0105 [8]
Spectral type	Tholen = C [4] [5] B–V = 0.705 [4] U–B = 0.315 [4]
Absolute magnitude (H)	10.4 [1] [4] [8] [9] [11] [12] · 10.450±0.002 (R) [14] · 10.507±0.014 [15] · 10.51 [5] · 10.53 [10]

1082 Pirola /ˈpɪrələ/ is a dark Themistian asteroid from the outer regions of the asteroid belt. It was discovered on 28 October 1927, by German astronomer Karl Reinmuth at the Heidelberg-Königstuhl State Observatory in Germany, and assigned the provisional designation 1927 UC. ^[1] The carbonaceous C-type asteroid has a rotation period of 15.9 hours and measures approximately 41 kilometers (25 miles) in diameter. It was named after the herbaceous plant Pyrola (wintergreen). ^[3]

Orbit and classification

When applying the hierarchical clustering method to its proper orbital elements, Pirola is a Themistian asteroid that belongs to the Themis family ( 602), ^{[18] [6] [7]} a large family of nearly 6,000 known carbonaceous asteroids, named after 24 Themis. ^[19]: 23 It orbits the Sun in the outer main belt at a distance of 2.6–3.7  AU once every 5 years and 6 months (2,013 days; semi-major axis of 3.12 AU). Its orbit has an eccentricity of 0.18 and an inclination of 2 ° with respect to the ecliptic. ^[4] The asteroid was first identified as A916 UP at Simeiz Observatory in October 1916. The body's observation arc begins with its official discovery observation at Heidelberg in October 1927. ^[1]

Naming

This minor planet was named after Pyrola, also known as wintergreen, a herbaceous plant (mostly evergreen), that belongs to the flowering herbs. The official naming citation was mentioned in The Names of the Minor Planets by Paul Herget in 1955 ( H 102). ^[3]

Reinmuth's flowers

Karl Reinmuth submitted a large list of 66 newly named asteroids in the early 1930s. The list covered his discoveries with numbers between (1009) and (1200). This list also contained a sequence of 28 asteroids, starting with 1054 Forsytia, that were all named after plants, in particular flowering plants (also see list of minor planets named after animals and plants). ^[20] (Unusually the Pirola has lent its name to a COVID-19 variant: BA.2.86. ^[21])

Physical characteristics

In the Tholen classification, Pirola is a carbonaceous C-type asteroid, ^{[4] [5]} which matches the overall spectral type of the Themis family. ^[19]: 23

Rotation period

In 2010, three rotational lightcurves of Pirola were obtained from photometric observations. Lightcurve analysis gave a rotation period of 15.85, 15.851 and 15.8525 hours with a brightness amplitude between 0.53 and 0.62 magnitude ( U=3-/2/3). ^{[13] [14] [15]}

A 2016-published lightcurve, using modeled photometric data from the Lowell Photometric Database, gave a concurring period of 15.8540 hours, as well as two spin axis of (123.0°, −42.0°) and (300.0°, −38.0°) in ecliptic coordinates (λ, β). ^[16]

Diameter and albedo

According to the surveys carried out by the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Pirola measures between 37.363 and 44.67 kilometers in diameter and its surface has an albedo between 0.052 and 0.0867. ^{[8] [9] [10] [11] [12] [17]} The Collaborative Asteroid Lightcurve Link derives an albedo of 0.0655 and a diameter of 41.06 kilometers based on an absolute magnitude of 10.51. ^[5]

References

External links

• Lightcurve Database Query (LCDB), at www.minorplanet.info
• Dictionary of Minor Planet Names, Google books
• Asteroids and comets rotation curves, CdR – Geneva Observatory, Raoul Behrend
• Discovery Circumstances: Numbered Minor Planets (1)-(5000) – Minor Planet Center
• 1082 Pirola at AstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 1082 Pirola at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit diagram · Orbital elements · Physical parameters