(809) Lundia

Asteroid (809) Lundia

Properties of the orbit ( animation ) Epoch: 4th September 2017 ( JD 2,458,000.5)
Orbit type	Inner main belt
Major semi-axis	2.2833 AU
eccentricity	0.1926
Perihelion - aphelion	1.8435 AU - 2.7230 AU
Inclination of the orbit plane	7.148 °
Length of the ascending node	154.578 °
Argument of the periapsis	196.179 °
Time of passage of the perihelion	April 18, 2019
Sidereal period	3 a 165.2 d
Mean orbital velocity	19.71 km / s
Physical Properties
Medium diameter	6.9 ± 2.4
Dimensions	4.86 · 10 ¹⁴ (system) kg
Albedo	0.379 ± 0.084
Medium density	2.5 ± 0.2 g / cm³
Rotation period	15 h 24.9 min 56.7 s
Absolute brightness	12.2 mag
Spectral class	V
history
Explorer	Max FJC Wolf
Date of discovery	August 11, 1915
Another name	1915 XP, 1936 VC
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.

(809) Lundia is an asteroid located in the main inner belt . The asteroid has a diameter of 6.9 km. Together with its moon S / 2005 (809) 1 , which is slightly smaller than Lundia with a diameter of about 6.1 km, Lundia forms a double asteroid system .

Discovery and naming

Lundia was discovered on August 11, 1915 by the German astronomer Maximilian Franz Joseph Cornelius Wolf at the State Observatory Heidelberg-Königstuhl near Heidelberg .

The celestial body was named after the Swedish city of Lund , the location of the Old Lund Observatory .

Since the companion's discovery, the name "Lundia" has officially been used for the larger component, while the designation S / 2005 (809) 1 applies to the smaller component. But the name is often used for the whole system.

In total, the asteroid was observed through several earth-based telescopes, a total of 2408 times within 101 years. (As of Sept. 2017)

Track properties

Orbit

Lundia orbits the Sun in a prograde , elliptical orbit between 275,787,000 km (1.84 AU ) and 407,355,000 km (2.72 AU) from its center. The orbital eccentricity is 0.193, the web is about 7.15 ° relative to the ecliptic inclined . Its orbit is therefore in the inner asteroid belt .

The orbital period of Lundia is 3.45 years.

Lundia's orbit is within (8) Flora family, a number of S-class asteroids that orbit the Sun in similar orbits between 2.15 and 2.35 AU and are likely fragments of a previous collision. The V-type spectrum, however, indicates a different origin; possibly Lundia is a fragment of a large earlier impact on Vesta , or two fragments if one includes the companion S / 2005 (809) 1 . However, Lundia's orbit is too far from Vesta to be a member of the Vesta family , so it is unclear how the two Lundia components got onto such an orbit; however, other members of the V-type asteroids are also quite far removed from the named body of origin. An interplay between the Jarkowski effect and nonlinear secular resonances has been suggested, involving mainly the planets Jupiter and Saturn . Lundia is therefore likely an interloper within the Flora family.

rotation

Lundia rotates around its axis once every 15 hours and 24.9 minutes. It follows that the asteroid 1961.9 in a Lundia-year own twists performs. Since the orbit time is the same as the rotation time, and the companion S / 2005 (809) 1 behaves in the same way, it is a doubly bound rotation . This means that both bodies always turn to the same side, as is the case with the Pluto / Charon or Antiope A / B systems . The prerequisite for this is a similar mass ratio and a narrow orbit of the two bodies.

Observations of the light curve show an alignment of Lundia's pole in the direction of the ecliptic coordinates with 5 ° uncertainty. ${\ displaystyle (\ beta, \ lambda) = (122 ^ {\ circ}, 22 ^ {\ circ})}$

Physical Properties

size

The single body diameter (effective system diameter) is currently estimated at 9.6 km. Due to the dual nature of the Lundia system, the actual mean diameter of Lundia itself ( geometric mean ) is estimated at 6.9 km; it is only 11.6% larger than its companion S / 2005 (809) 1 . The exact dimensions are currently unclear, but at least one of the two components has an elongated shape.

Assuming a mean diameter of 6.9 km, the surface area is about 150 km ² , which is just below the area of Liechtenstein .

Provisions of the diameter for Lundia

year	Dimensions km	source
2009	9.1 ± 3.1	Kryszczyńska u. a.
2009	6.9 ± 2.4	Kryszczyńska u. a.
2012	10.26 ± 0.07	Carry u. a.
2014	9.450 ± 0.184	Masiero et al. a.
2014	7.7	Kryszczyńska u. a.
2017	9.6 ± 1.1	Bartczak et al. a.

The most precise / most recent determination is marked in bold .

internal structure

Lundia belongs to the V-type asteroids and therefore has a very bright surface with an albedo of 0.379. The mean density of 2.5 g / cm ³ is an indication that it is not a compact body, but that the asteroid is likely to be a rubble pile , an accumulation of dust and rocks that is interspersed with cavities. The porosity is estimated at 13 to 30%. The original estimate of the density was based on 1.67 ± 0.04 g / cm ³ , which means that the porosity would be significantly higher.

The total mass of the system is . Since the companion has only slightly less mass than the main body, the barycentre of the system is also almost in the middle. ${\ displaystyle 4 {,} 86 \ cdot 10 ^ {14} \ {\ rm {kg}}}$

The mean surface temperature is around 165 to 180 K (−108 to −93 ° C) and can rise to a maximum of 260 to 280 K (−13 to +7 ° C) at noon.

Double system

On September 18, 2005 the existence of a moon of Lundia could be derived from observations of the light curve , which was given the provisional designation S / 2005 (809) 1 . This companion has a diameter of 6.1 kilometers and circles the common barycentre in 0.64 days within Lundia's Hill radius (1,200 km) at a distance of almost 16 km.

The similar sizes of the two components are revealed by mutual coverages; the brightness drops in a similar ratio, regardless of which component is currently hidden. Because of the comparable sizes, the Minor Planet Center lists the system as a double system.

The Lundia 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 Lundia's equator	Date of discovery Date of publication
(809) Lundia	6.9	100.0	?	-	-	-	-	August 11, 1915 49150000 ♠1915
S / 2005 (809) 1 (Lundia I)	6.1	88.4	?	15.8	0.6423225	?	?	September 18, 2005 October 1, 2005 50051001 ♠0

Web links

Wm. Robert Johnston: (809) Lundia (English)
Representation of 3-D model from (809) Lundia and S / 2005 (809) 1 (English)

Individual evidence

↑ (809) Lundia in the Small-Body Database of the Jet Propulsion Laboratory (English).
^ V. Carruba et al .: On the V-type asteroids outside the Vesta family (June 2005). Retrieved September 22, 2017 .
↑ Agnieszka Kryszczyńska et al.: 809 Lundia - a new synchronous V-type binary in the Flora family. Retrieved September 22, 2017 .
^ Daniel WE Green: (809) Lundia (October 2005). Retrieved September 22, 2017 .
↑ ^a ^b Agnieszka Kryszczyńska et al: New binary asteroid 809 Lundia I. Photometry and modeling (February 2009). Retrieved September 22, 2017 .
↑ Benoit Carry et al.: Density of asteroids . December 2012, bibcode : 2012P & SS ... 73 ... 98C .
^ Joseph R. Masiero et al.: Main-belt Asteroids with WISE / NEOWISE: Near-infrared Albedos . August 2014, bibcode : 2014ApJ ... 791..121M .
↑ Agnieszka Kryszczyńska et al: Non-convex model of the binary asteroid (809) Lundia and its density estimation (2014). Retrieved September 22, 2017 .
↑ Przemyslaw Bartczak et al: A new non-convex model of the binary asteroid (809) Lundia obtained with the SAGE modeling technique (July 2017). Retrieved September 22, 2017 .
^ Minor Planet Center: Satellites and Companions of Minor Planets. Accessed March 31, 2018 .

[JPL-1] (809) Lundia in the Small-Body Database of the Jet Propulsion Laboratory (English).

[carruba-2] V. Carruba et al .: On the V-type asteroids outside the Vesta family (June 2005). Retrieved September 22, 2017 .

[kryszczyńska-3] Agnieszka Kryszczyńska et al.: 809 Lundia - a new synchronous V-type binary in the Flora family. Retrieved September 22, 2017 .

[CBET_239-4] Daniel WE Green: (809) Lundia (October 2005). Retrieved September 22, 2017 .

[kryszczyńska2009-5] Agnieszka Kryszczyńska et al: New binary asteroid 809 Lundia I. Photometry and modeling (February 2009). Retrieved September 22, 2017 .

[carry2012-6] Benoit Carry et al.: Density of asteroids . December 2012, bibcode : 2012P & SS ... 73 ... 98C .

[masiero2014-7] Joseph R. Masiero et al.: Main-belt Asteroids with WISE / NEOWISE: Near-infrared Albedos . August 2014, bibcode : 2014ApJ ... 791..121M .

[kryszczyńska2014-8] Agnieszka Kryszczyńska et al: Non-convex model of the binary asteroid (809) Lundia and its density estimation (2014). Retrieved September 22, 2017 .

[bartczak2017-9] Przemyslaw Bartczak et al: A new non-convex model of the binary asteroid (809) Lundia obtained with the SAGE modeling technique (July 2017). Retrieved September 22, 2017 .

[mpc-10] Minor Planet Center: Satellites and Companions of Minor Planets. Accessed March 31, 2018 .