(41) Daphne

Asteroid (41) Daphne
Properties of the orbit ( animation ) Epoch: May 31, 2020 ( JD 2,459,000.5)
Orbit type	Main belt
Major semi-axis	2.761 AU
eccentricity	0.275
Perihelion - aphelion	2.002 AU - 3.521 AU
Inclination of the orbit plane	15.8 °
Length of the ascending node	178.1 °
Argument of the periapsis	45.9 °
Time of passage of the perihelion	March 12, 2022
Sidereal period of rotation	4 a 215 d
Mean orbital velocity	17.58 km / s
Physical Properties
Medium diameter	205.5 ± 1.9 km
Dimensions	239 km × 183 km × 153 km
Dimensions	(6.8 ± 0.1) ∙ 10 ¹⁸ kg
Albedo	0.059
Medium density	2.4 ± 0.7 g / cm³
Rotation period	5 h 59 min 36 s
Absolute brightness	7.4 mag
Spectral class (according to Tholen)	C.
Spectral class (according to SMASSII)	Ch
history
Explorer	Hermann MS Goldschmidt
Date of discovery	May 22, 1856
Another name	1949 TGS
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.

(41) Daphne is an asteroid found in the main central asteroid belt . With a diameter of 205 km, it is one of the largest asteroids in the main belt and it has a small moon called Peneius .

Discovery and naming

Daphne was discovered on May 22, 1856 by the Franco-German astronomer Hermann Mayer Salomon Goldschmidt at the Paris Observatory . Incorrect orbit calculations led to the discovery of (56) Melete , which at first was mistakenly taken for a second sighting by Daphne; However, this did not take place until six years later on August 31, 1862.

The then director of the observatory, Urbain Le Verrier , named the celestial body after Daphne , a nymph in Greek mythology who fled from the god Apollo and was turned into a laurel tree.

In 1999, Daphne covered three stars and another occlusion from TYC 0380 00670 on July 2 of the same year indicated an ellipsoid of 213 × 160 km. The light curve observations suggested an irregularly shaped body.

In total, the asteroid has been observed through several earth-based telescopes, a total of 2,461 times within 153 years. (As of Sept. 2019)

Track properties

Orbit

Daphne orbits the sun in a prograde , very elliptical orbit between 299,100,000 km (1.99 AU ) and 526,900,000 km (3.52 AU) from its center. The orbit eccentricity is 0.276, the orbit is inclined by 15.79 ° in relation to the ecliptic . Its orbit is therefore in the middle asteroid belt .

The orbit period of Daphne is 4.59 years. Overall, its orbital elements resemble those of (93) Minerva (4.57 years orbital period).

Railway resonance

Daphne's orbit is in a 9:22 orbit resonance with the planet Mars . The Lyapunov period is calculated to be 14,000 years, which indicates an unstable orbit; the orbit is perturbed by the planet and will change in unpredictable ways over time.

rotation

Daphne rotates once every 5 hours and 59 minutes on its axis. From this it follows that the asteroid performs 6714.4 self- rotations in one Daphne year .

Physical Properties

size

The observations made so far indicate an irregularly shaped, elongated body; the most precise determination of the diameter is 205.495 km. Regarding the exact dimensions, the most precise value is 239 × 183 × 153 km, which means that Daphne should be roughly similar in shape to Jupiter's moon Amalthea .

Assuming a mean diameter of 205 km, this results in a surface area of around 130,000 km ² , which roughly corresponds to the area of Greece .

Provisions of the diameter for Daphne

year	Dimensions	source
1999	213 × 160	Dusser et al. a.
2002	174 ± 11.7	Tedesco ( IRAS ) u. a.
2008	239 × 213 × 153	Kaasalainen et al. a.
2011	189	Matter u. a.
2011	194 to 209	Matter u. a.
2012	205.495 ± 1.881	Masiero et al. a.

The most precise determination is marked in bold .

internal structure

The surface of the asteroid is extremely dark with an albedo of 0.059, it possibly consists of primitive carbonaceous chondrites . The density is between 1.95 and 2.4 g / cm ³ ; the latter value was determined in April 2008 by the Arecibo radio telescope . So far, the mass has been calculated to be between 5.5 and 6.8 ∙ 10 ¹⁸ . The mean surface temperature is around 167 K (−106 ° C).

Daphne's absolute magnitude is given as 7.12 mag.

moon

On March 28, 2008 the discovery of a moon around Daphne was announced, which was given the provisional designation S / 2008 (41) 1 and on March 6, 2019 the name Peneius . The discovery is based on observations of light curves from various observatories. The moon has a diameter of almost two kilometers, which is the most extreme known size ratio of all asteroids in the solar system to date. The distance to the main body is given as 405 kilometers.

The Daphne 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 Daphne's equator	Date of discovery Date of publication
(41) Daphne	205.5	100.00	6.8 10 ¹⁸	-	-	-	-	May 22, 1856 48560000 ♠1856
Peneius (Daphne I)	2.0	1.0	?	405	1.1	?	?	March 28, 2008 50080331 ♠March 31, 2008

Web links

Wm. Robert Johnston: (41) Daphne and S / 2008 (41) 1 (English)
Asteroid 41 Daphne Interactive look-up map of Daphne
Asteroid (41) Daphne Rotatable 3D model of Daphne (English)

Individual evidence

↑ W. Thuillot u. a .: Astrometric parameters of asteroids from stellar occultations . 1999, bibcode : 1999DPS .... 31.5913T .
↑ (41) Daphne in the Small-Body Database of the Jet Propulsion Laboratory (English).
^ Raymond Dusser et al. a .: 1999 European Asteroidal Occultation Results (1999). (PDF) Retrieved September 1, 2017 .
^ Wm. Robert Johnston: (41) Daphne and S / 2008 (41) 1 (2014). Retrieved September 1, 2017 .
↑ Kaasalainen et al. a .: Shape and Size of Asteroid (41) Daphne from AO Imaging . 2008, bibcode : 2008DPS .... 40.2812C .
↑ ^a ^b Alexis Matter u. a .: Determination of physical properties of the Asteroid (41) Daphne . 2011, bibcode : 2011Icar..215 ... 47M .
↑ Joseph R. Masiero et al. a .: Preliminary Analysis of WISE / NEOWISE 3-Band Cryogenic and Post-cryogenic Observations of Main Belt Asteroids . 2012, bibcode : 2012ApJ ... 759L ... 8M .
↑ Gareth V. Williams: MPEC 2019-E58: Satellite of (41) Daphne. Retrieved September 24, 2019 .
^ Wm. Robert Johnston: (41) Daphne

[thuillot-1] W. Thuillot u. a .: Astrometric parameters of asteroids from stellar occultations . 1999, bibcode : 1999DPS .... 31.5913T .

[2] (41) Daphne in the Small-Body Database of the Jet Propulsion Laboratory (English).

[Euraster-3] Raymond Dusser et al. a .: 1999 European Asteroidal Occultation Results (1999). (PDF) Retrieved September 1, 2017 .

[Johnson-4] Wm. Robert Johnston: (41) Daphne and S / 2008 (41) 1 (2014). Retrieved September 1, 2017 .

[kaasalainen-5] Kaasalainen et al. a .: Shape and Size of Asteroid (41) Daphne from AO Imaging . 2008, bibcode : 2008DPS .... 40.2812C .

[matter-6] Alexis Matter u. a .: Determination of physical properties of the Asteroid (41) Daphne . 2011, bibcode : 2011Icar..215 ... 47M .

[masiero-7] Joseph R. Masiero et al. a .: Preliminary Analysis of WISE / NEOWISE 3-Band Cryogenic and Post-cryogenic Observations of Main Belt Asteroids . 2012, bibcode : 2012ApJ ... 759L ... 8M .

[Mpec2019E58-8] Gareth V. Williams: MPEC 2019-E58: Satellite of (41) Daphne. Retrieved September 24, 2019 .

[9] Wm. Robert Johnston: (41) Daphne