(45) Eugenia

Asteroid (45) Eugenia
Properties of the orbit ( animation ) Epoch: 4th September 2017 ( JD 2,458,000.5)
Orbit type	Middle main belt
Major semi-axis	2.7195 AU
eccentricity	0.0840
Perihelion - aphelion	2.4911 AU - 2.9480 AU
Inclination of the orbit plane	6.604 °
Length of the ascending node	147.671 °
Argument of the periapsis	88.756 °
Time of passage of the perihelion	5th November 2018
Sidereal period	4 a 178 d
Mean orbital velocity	18.03 km / s
Physical Properties
Medium diameter	202.3 ± 2.2 km
Dimensions	232 × 193 × 161 km
Dimensions	5.69 ± 0.1 x 10 ¹⁸ kg
Albedo	0.046 ± 0.006
Medium density	1.12 ± 0.10 g / cm³
Rotation period	5 h 42 min
Absolute brightness	7.46 likes
Spectral class	FC
history
Explorer	Hermann MS Goldschmidt
Date of discovery	June 27, 1857
Another name	1941 BN
Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . The affiliation to an asteroid family is automatically determined from the AstDyS-2 database . Please also note the note on asteroid items.

(45) Eugenia is an asteroid in the main asteroid belt . With a diameter of 202 km, Eugenia is one of the largest asteroids in the main belt.

Discovery and naming

Eugenia was discovered on June 27, 1857 by the Franco-German astronomer Hermann Mayer Salomon Goldschmidt . The discovery was made with a 4-inch telescope stationed in his apartment on the 6th floor in the Latin Quarter in Paris . A preliminary orbit calculation was carried out by Wilhelm Foerster in Berlin after he had observed the asteroid three times in July 1857.

The celestial body was named in honor of Eugénie de Montijo , the wife of Napoleon III. Eugenia was the first asteroid to be named after a living person with certainty. Previously, there has been controversy over whether (12) Victoria was named after Queen Victoria or Victoria from Roman mythology .

In total, the asteroid was observed through several earth-based telescopes, a total of 2721 times within 150 years. (As of Sept. 2017)

Track properties

Orbit

Eugenia orbits the sun in a prograde , elliptical orbit between 372,600,000 km (2.49 AU ) and 441,000,000 km (2.94 AU) from its center. The orbital eccentricity is 0.084, the web is about 6.6 ° relative to the ecliptic inclined . Its orbit is therefore in the middle asteroid belt .

The orbital period of Eugenia is 4.48 years.

rotation

Eugenia rotates around its axis once every 5 hours and 41.9 minutes. From this it follows that the asteroid performs 6,898.5 self- rotations ("days") in a Eugenia year .

Observations of the light curve show an alignment of Eugenia's pole in the direction of the ecliptic coordinates with 10 ° uncertainty; this results in an axis inclination of 113 °; Eugenia's rotation is therefore retrograde . ${\ displaystyle (\ beta, \ lambda) = (- 30 ^ {\ circ}, 124 ^ {\ circ})}$

Physical Properties

size

The previous observations indicate an asymmetrical, irregularly shaped, elongated body; the most precise determination of the diameter ( geometric mean ) is 202.327 km. With regard to the exact dimensions, the most precise value is 232 × 193 × 161 km.

Assuming a mean diameter of 202.3 km, the surface area is about 129,000 km ² , which is just about the area of Greece .

Provisions of the diameter for Eugenia

year	Dimensions km	source
1999	308 × 220 × 147	Merline et al. a.
2002	305 × 220 × 145	Tedesco ( IRAS ) u. a.
2008	232 × 193 × 161	Marchis et al. a.
2010	214.6 ± 4.2	Kaasalainen et al. a.
2012	206.14 ± 6.22	Masiero et al. a.
2014	202.327 ± 2.168	Masiero et al. a.

The most precise determination is marked in bold .

internal structure

Eugenia belongs to the F-type asteroids and therefore has a dark, carbon-rich surface with an albedo of 0.04. The surface color is therefore darker than coal. The unusually low mean density of 1.12 g / cm ³ indicates that the celestial body is likely to be a rubble pile , a loose accumulation of dust and rocks. The asteroid appears to have practically no water reserves. With regard to its composition, Eugenia can be easily compared with (253) Mathilde .

The mass of Eugenia has so far been calculated to be 5.69 ∙ 10 ¹⁸ . The absolute brightness is given as 7.46 mag.

The mean surface temperature is around 171 K (−102 ° C) and can rise to a maximum of 253 K (−20 ° C) at noon.

The Eugenia triple system

On October 6, 1999 , a natural satellite was discovered near Eugenia and named after the little prince of Antoine de Saint-Exupéry Petit-Prince , also in honor of the only son Napoléon Eugène Louis Bonaparte, the imperial namesake of the mother's body. It is a 7 km body that orbits Eugenia at a distance of 1,164 km in 4.716 days. After Dactyl , this was the second discovery of an asteroid moon.

In March 2007, the discovery of a second moon was announced. The 5 km object, which was given the provisional name S / 2004 (45) 1 , orbits Eugenia within the Petit-Prince orbit and was discovered on images from 2004. This made the Eugenia system the second multiple asteroid system discovered after (87) Sylvia . This companion is mostly referred to as Princesse in analogy to Petit-Prince , but an official name confirmation from the IAU is still pending. The moon orbits Eugenia at a distance of 611 km in 1.793 days.

Overall, the Eugenia system appears to be quite stable; there are no signs of orbital disturbances of the two moons due to orbital resonances , not even for the Kozai effect , which indicates that the inclinations of the orbits of the moons were not caused by the influence of Eugenia. A 10-year evolutionary study of the system indicates that the orbits of Petit-Prince and S / 2004 (45) 1 are slightly perturbed by the sun , and to a lesser extent by the mutual interactions between the moons.

The Eugenia system at a glance
Components	Physical parameters			Path parameters				discovery
Surname	Throughput diameter (km)	Relative size %	Mass (kg)	Major semi-axis (km)	Orbital time (d)	eccentricity	Inclination to Eugenia's equator	Date of discovery Date of publication
(45) Eugenia	202.3	100.00	5.6 10 ¹⁸	-	-	-	-	June 27, 1857 48570628 ♠June 28, 1857
S / 2004 (45) 1 ( "Princesse" ) (Eugenia II)	5.0	2.47	?	610.59	1.793	0.110	18.0	February 14, 2004 March 7, 2007 50070307 ♠0
Petit Prince (Eugenia I)	7.0	3.46	1.2 · 10 ¹⁵	1164.42	4.716	0.002	8.0	November 1, 1998 49990320 ♠March 20, 1999

Web links

Wm. Robert Johnston: (45) Eugenia, Petit-Prince, and S / 2004 (45) 1 (English)
Asteroid 45 Eugenia Interactive map of Eugenia
Asteroid (45) Eugenia Rotatable 3D model of Eugenia (English)

Individual evidence

^ Dictionary of Minor Planet Names, Volume 1 in the Google Book Search
↑ (45) Eugenia in the Small-Body Database of the Jet Propulsion Laboratory (English).
↑ ^a ^b Jim Baer: Recent Asteroid Mass Determinations (2010). (No longer available online.) Archived from the original on July 8, 2013 ; accessed on September 4, 2017 .
↑ IRAS (2001): The Supplemental IRAS Minor Planet Survey. Retrieved September 13, 2017 .
↑ M. Kaasalainen et al. a .: Models of Twenty Asteroids from Photometric Data . 2002, bibcode : 2002Icar..159..369K .
↑ Joseph R. Masiero et al. a .: Main-belt Asteroids with WISE / NEOWISE: Near-infrared Albedos . 2012, arxiv : 1209.5794 .
↑ Joseph R. Masiero et al. a .: Main-belt Asteroids with WISE / NEOWISE: Near-infrared Albedos . 2014, bibcode : 2014ApJ ... 791..121M .
↑ IAUC 7503: Satellites of minor planets October 3, 2000 (designation; English)
^ William J. Merline, Laird M. Close, Christophe Dumas, Clark R. Chapman, François Roddier, François Menard, David C. Slater, Gilles Duvert, J. Chris Shelton and Thomas Morgan: On a Permanent Name for Asteroid S / 1998 (45) 1. Southwest Research Institute Planetary Science Directorate, University of Colorado at Boulder , May 26, 2000 (proposed name).
↑ Asteroids with Satellites - (45) Eugenia, Petit-Prince, and S / 2004 (45) 1
↑ Franck Marchis et al. a .: A Dynamical Solution of the Triple Asteroid System (45) Eugenia . 2010, arxiv : 1008.2164 .

[1] Dictionary of Minor Planet Names, Volume 1 in the Google Book Search

[JPL-2] (45) Eugenia in the Small-Body Database of the Jet Propulsion Laboratory (English).

[baer-3] Jim Baer: Recent Asteroid Mass Determinations (2010). (No longer available online.) Archived from the original on July 8, 2013 ; accessed on September 4, 2017 .

[iras-4] IRAS (2001): The Supplemental IRAS Minor Planet Survey. Retrieved September 13, 2017 .

[kaasalainen-5] M. Kaasalainen et al. a .: Models of Twenty Asteroids from Photometric Data . 2002, bibcode : 2002Icar..159..369K .

[Masiero1-6] Joseph R. Masiero et al. a .: Main-belt Asteroids with WISE / NEOWISE: Near-infrared Albedos . 2012, arxiv : 1209.5794 .

[Masiero2-7] Joseph R. Masiero et al. a .: Main-belt Asteroids with WISE / NEOWISE: Near-infrared Albedos . 2014, bibcode : 2014ApJ ... 791..121M .

[8] IAUC 7503: Satellites of minor planets October 3, 2000 (designation; English)

[9] William J. Merline, Laird M. Close, Christophe Dumas, Clark R. Chapman, François Roddier, François Menard, David C. Slater, Gilles Duvert, J. Chris Shelton and Thomas Morgan: On a Permanent Name for Asteroid S / 1998 (45) 1. Southwest Research Institute Planetary Science Directorate, University of Colorado at Boulder , May 26, 2000 (proposed name).

[10] Asteroids with Satellites - (45) Eugenia, Petit-Prince, and S / 2004 (45) 1

[marchis-11] Franck Marchis et al. a .: A Dynamical Solution of the Triple Asteroid System (45) Eugenia . 2010, arxiv : 1008.2164 .