astro.wikisort.org - Asteroid

789 Lena, provisional designation 1914 UU, is a metallic asteroid from the middle region of the asteroid belt, approximately 24 kilometers in diameter. It was discovered on 24 June 1914, by Soviet–Russian astronomer Grigory Neujmin at Simeiz Observatory on the Crimean peninsula, and named after the discoverer's mother.[13]

789 Lena

Discovery [1]
Discovered by	G. Neujmin
Discovery site	Simeiz Obs.
Discovery date	24 June 1914
Designations
MPC designation	(789) Lena
Pronunciation	/ˈleɪnə/[2]
Named after	Elena Neujmina (discoverer's family)[3]
Alternative designations	1914 UU · 1970 CE
Minor planet category	main-belt · (middle) [4]
Orbital characteristics [1]
Epoch 16 February 2017 (JD 2457800.5)
Uncertainty parameter 0
Observation arc	81.69 yr (29,837 days)
Aphelion	3.0817 AU
Perihelion	2.2907 AU
Semi-major axis	2.6862 AU
Eccentricity	0.1472
Orbital period (sidereal)	4.40 yr (1,608 days)
Mean anomaly	110.02°
Mean motion	0° 13m 26.04s / day
Inclination	10.781°
Longitude of ascending node	232.62°
Argument of perihelion	44.006°
Physical characteristics
Dimensions	20.56±0.34 km[5] 22.483±0.306[6] 23.871±0.162 km[7] 24.18 km (calculated)[4]
Synodic rotation period	5.84239±0.00001 h[8] 5.848±0.001 h[9] 5.85±0.05 h[10] 22 h[11]
Geometric albedo	0.10 (assumed)[4] 0.1373±0.0147[7] 0.153±0.028[6] 0.186±0.007[5]
Spectral type	SMASS = X [1] · M [7] · X [4]
Absolute magnitude (H)	10.47±0.60[12] · 10.9[5][7] · 11.2[1][4]

Orbit and classification

Lena orbits the Sun in the middle main-belt at a distance of 2.3–3.1 AU once every 4 years and 5 months (1,608 days). Its orbit has an eccentricity of 0.15 and an inclination of 11° with respect to the ecliptic.[1] Lena's observation arc begins with its first used observation made at Yerkes Observatory in 1935, or 21 years after its official discovery observation at Simeiz.[13]

Although its orbital elements resemble those of the asteroids in the Eunomia family, true members of this family have a S-type composition, so it is almost certainly an unrelated interloper.^{[citation needed]}

Physical characteristics

In the SMASS taxonomy, Lena is an X-type asteroid. It has also been characterized as a metallic M-type asteroid by NASA's Wide-field Infrared Survey Explorer (WISE).[7]

Rotation period

In 1993, a rotational lightcurve which was later proven incorrect, was obtained from photometric observations at the Félix Aguilar Observatory, Argentina. It gave an unusual lightcurve, indicating a very irregular shape and/or a relatively long rotation period of 22 hours with an exceptionally high amplitude of 1.5 in magnitude (U=0).[11]

In August and September 2007, two reliable lightcurves were obtained by Italian astronomer Silvano Casulli and by members at the U.S.Oakley Observatory. Lightcurve analysis gave a period of 5.848±0.001 and 5.85±0.05 hours, with a brightness variation of 0.50 and of 0.40 magnitude, respectively (U=3/2+).[lower-alpha 1][9][10]

Diameter and albedo

According to the space-based surveys carried out by the Japanese Akari satellite and the NEOWISE mission of the WISE telescope, Lena measures between 20.6 and 23.9 kilometers in diameter, and its surface has an albedo of 0.137–0.186.[5][6][7] The Collaborative Asteroid Lightcurve Link assumes a much lower albedo of 0.10 and calculates a diameter of 24.2 kilometer, as the lower the albedo (reflectivity), the larger a body's diameter, at a constant absolute magnitude (brightness).[4]

Naming

This minor planet was named in honor of Elena ("Lena") Petrovna Neujmina (1860–1942), mother of the discovering astronomer Grigory Neujmin.[3]

Notes

References

External links

• Asteroid Lightcurve Database (LCDB), query form (info Archived 16 December 2017 at the Wayback Machine)
• Dictionary of Minor Planet Names, Google books
• Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend
• Discovery Circumstances: Numbered Minor Planets (1)-(5000) – Minor Planet Center
• 789 Lena at AstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 789 Lena at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit diagram · Orbital elements · Physical parameters

На других языках

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[de] (789) Lena

(789) Lena ist ein Asteroid des Hauptgürtels, der am 24. Juni 1914 vom russischen Astronomen Grigori Nikolajewitsch Neuimin in Simejis entdeckt wurde.

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- [en] 789 Lena

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[ru] (789) Лена

(789) Лена (лат. Lena) — небольшой астероид главного пояса, принадлежащий к спектральному классу X. Он был обнаружен 24 июня 1914 года советским астрономом Григорием Неуйминым в Симеизской обсерватории и назван в честь матери первооткрывателя Елены Петровны Неуйминой[1].

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