astro.wikisort.org - Asteroid

873 Mechthild (prov. designation: A917 KJ or 1917 CA) is a dark background asteroid from the central regions of the asteroid belt. It was discovered by German astronomer Max Wolf at the Heidelberg Observatory on 21 May 1917.[1] The primitive P-type asteroid has a rotation period of 11.0 hours and measures approximately 34 kilometers (21 miles) in diameter. The origin of the asteroid's name remains unknown.[2]

873 Mechthild

Modelled shape of Mechthild from its lightcurve
Discovery [1]
Discovered by	M. F. Wolf
Discovery site	Heidelberg Obs.
Discovery date	21 May 1917
Designations
MPC designation	(873) Mechthild
Named after	unknown [2]
Alternative designations	A917 KJ · 1917 CA
Minor planet category	main-belt [1][3] · (middle) background [4][5]
Orbital characteristics [3]
Epoch 31 May 2020 (JD 2459000.5)
Uncertainty parameter 0
Observation arc	102.24 yr (37,343 d)
Aphelion	3.0199 AU
Perihelion	2.2346 AU
Semi-major axis	2.6273 AU
Eccentricity	0.1495
Orbital period (sidereal)	4.26 yr (1,555 d)
Mean anomaly	48.264°
Mean motion	0° 13m 53.04s / day
Inclination	5.2763°
Longitude of ascending node	150.00°
Argument of perihelion	109.99°
Physical characteristics
Mean diameter	29.04±1.9 km[6] 33.56±0.59 km[7] 34.471±0.103 km[8]
Synodic rotation period	11.006±0.001 h[9]
Pole ecliptic latitude	(249.0°, −52.0°) (λ1/β1)[5] (51.0°, −61.0°) (λ2/β2)[5]
Geometric albedo	0.040±0.004[8] 0.041±0.002[7] 0.0531±0.008[6]
Spectral type	Tholen = PC [3] C0 (Barucci) B–V = 0.684±0.022[3] U–B = 0.319±0.037[3]
Absolute magnitude (H)	11.4[1][3]

Orbit and classification

Mechthild 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 central asteroid belt at a distance of 2.2–3.0 AU once every 4 years and 3 months (1,555 days; semi-major axis of 2.63 AU). Its orbit has an eccentricity of 0.15 and an inclination of 5° with respect to the ecliptic.[3] The body's observation arc begins with its first and official discovery observation at Heidelberg Observatory on 21 May 1917.[1]

Naming

This minor planet is named "Mechthild", a German feminine given name. Any reference of this name to a specific person or occurrence is unknown.[2]

Unknown meaning

Among the many thousands of named minor planets, Mechthild is one of 120 asteroids, for which no official naming citation has been published. All of these low-numbered asteroids have numbers between 164 Eva and 1514 Ricouxa and were discovered between 1876 and the 1930s, predominantly by astronomers Auguste Charlois, Johann Palisa, Max Wolf and Karl Reinmuth (also see category).[10]

Physical characteristics

In the Tholen classification, Mechthild is closest to a very dark, primitive P-type, and somewhat similar to a common C-type asteroid. In the taxonomy by Barucci, it is a C0-type.[3][5] P-type asteroids are more common in the outer asteroid belt and among the Jupiter trojan population.

Rotation period

In May 2015, a rotational lightcurve of Mechthild was obtained from photometric observations by Brian Warner at his Palmer Divide Observatory (716) in Colorado. Lightcurve analysis gave a rotation period of 11.006±0.001 hours with a brightness amplitude of 0.27±0.02 magnitude (U=3).[9]

Alternative period determinations were made by Claes-Ingvar Lagerkvist (10.6 h) in March 1976, by astronomers at the Palomar Transient Factory (11.007±0.0069 h) in January 2014, and by the Spanish group of asteroid observers, OBAS (10.99±0.01 h) in May 2015 (U=2/2/3).[11][12][13] In 2016, a modeled lightcurve gave a concurring sidereal period of 11.00639±0.00005 hours using data from a large collaboration of individual observers (such as above). The study also determined two spin axes of (249.0°, −52.0°) and (51.0°, −61.0°) in ecliptic coordinates (λ, β).[14]

Diameter and albedo

According to the surveys carried out by the Infrared Astronomical Satellite IRAS, and the Japanese Akari satellite, and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer (WISE), Mechthild measures (29.04±1.9), (33.56±0.59) and (34.471±0.103) kilometers in diameter and its surface has an albedo of (0.0531±0.008), (0.041±0.002) and (0.040±0.004), respectively.[6][7][8] The Collaborative Asteroid Lightcurve Link adopts the results from IRAS, that is, an albedo of 0.0531 and a diameter of 29.04 kilometers based on an absolute magnitude of 11.49.[15] Alternative mean-diameter measurements published by the WISE team include (29.124±10.26 km) and (36.327±0.290 km) with corresponding albedos of (0.0785±0.0687) and (0.0339±0.0063).[15]

References

External links

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

На других языках

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[de] (873) Mechthild

(873) Mechthild ist ein Asteroid des Hauptgürtels, der am 21. Mai 1917 vom deutschen Astronomen Max Wolf in Heidelberg entdeckt wurde.

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- [en] 873 Mechthild

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[ru] (873) Мечтилд

(873) Мечтилд (нем. Mechthild) — астероид во внешней части главного пояса астероидов, принадлежащий к спектральному классу P. Астероид был открыт 21 мая 1917 года немецким астрономом Максом Вольфом в Гейдельбергской обсерватории.

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