4827 Dares

4827 Dares /ˈdɛəriːz/ is a larger Jupiter trojan from the Trojan camp, approximately 43 kilometers (27 miles) in diameter. It was discovered on 17 August 1988 by American astronomer Carolyn Shoemaker at the Palomar Observatory in California.[1] The dark D-type asteroid has a rotation period of 19.0 hours.[7] It was named after Dares from Greek mythology.[1]

4827 Dares
Discovery [1]
Discovered byC. Shoemaker
Discovery sitePalomar Obs.
Discovery date17 August 1988
Designations
(4827) Dares
Pronunciation/ˈdɛəriːz/[2]
Named after
Dares (Greek mythology)[1]
1988 QE
Jupiter trojan [1][3]
Trojan [4] · background [5]
Orbital characteristics [3]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc63.49 yr (23,191 d)
Aphelion5.3517 AU
Perihelion4.8903 AU
5.1210 AU
Eccentricity0.0451
11.59 yr (4,233 d)
119.05°
0° 5m 6.36s / day
Inclination7.7056°
242.04°
170.69°
Jupiter MOID0.0037 AU
TJupiter2.9800
Physical characteristics
Mean diameter
42.77±0.26 km[6]
44.22 km (calculated)[7]
18.995±0.028 h[8]
0.057 (assumed)[7]
0.067±0.007[6]
D (Pan-STARRS)[7][9]
D (SDSS-MOC)[10][11]
10.4[6]
10.5[1][3][7]
10.88±0.01[9]

    Orbit and classification

    Dares is a dark Jovian asteroid in a 1:1 orbital resonance with Jupiter. It is located in the trailering Trojan camp at the Gas Giant's L5 Lagrangian point, 60° behind on its orbit (see Trojans in astronomy). It is also a non-family asteroid of the Jovian background population.[5] It orbits the Sun at a distance of 4.9–5.4 AU once every 11 years and 7 months (4,233 days; semi-major axis of 5.12 AU). Its orbit has an eccentricity of 0.05 and an inclination of 8° with respect to the ecliptic.[3]

    The body's observation arc begins with a precovery at Palomar in November 1954, almost 34 years prior to its official discovery observation.[1]

    Physical characteristics

    In the SDSS-based taxonomy, Dares is a dark D-type asteroid.[10][11] It is also characterized as a D-type by Pan-STARRS' survey.[7][9]

    Rotation period

    In February 1994, a rotational lightcurve of Dares was obtained over five nights of observation by Stefano Mottola and Anders Erikson using the ESO 1-metre telescope at La Silla Observatory in Chile. Lightcurve analysis showed a well-defined rotation period of 18.995±0.028 hours with a brightness variation of 0.24 magnitude (U=3).[7][8]

    In October 2013, photometric observations in the R-band by astronomers at the Palomar Transient Factory in California gave a concurring period of 18.967 hours with an amplitude of 0.23 magnitude (U=2).[7][12]

    Diameter and albedo

    According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Dares measures 42.77 kilometers in diameter and its surface has an albedo of 0.067,[6] while the Collaborative Asteroid Lightcurve Link assumes a standard albedo for a carbonaceous asteroid of 0.057 and calculates a diameter of 44.22 kilometers based on an absolute magnitude of 10.5.[7]

    Naming

    This minor planet was named by the discoverer from Greek mythology after the Trojan Dares, one of Aeneas' wandering companions (Aeneads) who were not killed or enslaved by the end of the Trojan War.[1] The official naming citation was published by the Minor Planet Center on 25 August 1991 (M.P.C. 18647).[13]

    References
    1. "4827 Dares (1988 QE)". Minor Planet Center. Retrieved 21 June 2018.
    2. Noah Webster (1884) A Practical Dictionary of the English Language
    3. "JPL Small-Body Database Browser: 4827 Dares (1988 QE)" (2018-05-22 last obs.). Jet Propulsion Laboratory. Retrieved 21 June 2018.
    4. "List of Jupiter Trojans". Minor Planet Center. 1 June 2018. Retrieved 21 June 2018.
    5. "Asteroid (4827) Dares – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 21 June 2018.
    6. Grav, T.; Mainzer, A. K.; Bauer, J. M.; Masiero, J. R.; Nugent, C. R. (November 2012). "WISE/NEOWISE Observations of the Jovian Trojan Population: Taxonomy". The Astrophysical Journal. 759 (1): 10. arXiv:1209.1549. Bibcode:2012ApJ...759...49G. doi:10.1088/0004-637X/759/1/49. (online catalog)
    7. "LCDB Data for (4827) Dares". Asteroid Lightcurve Database (LCDB). Retrieved 21 June 2018.
    8. Mottola, Stefano; Di Martino, Mario; Erikson, Anders; Gonano-Beurer, Maria; Carbognani, Albino; Carsenty, Uri; et al. (May 2011). "Rotational Properties of Jupiter Trojans. I. Light Curves of 80 Objects". The Astronomical Journal. 141 (5): 32. Bibcode:2011AJ....141..170M. doi:10.1088/0004-6256/141/5/170.
    9. Veres, Peter; Jedicke, Robert; Fitzsimmons, Alan; Denneau, Larry; Granvik, Mikael; Bolin, Bryce; et al. (November 2015). "Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results". Icarus. 261: 34–47. arXiv:1506.00762. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007.
    10. Carvano, J. M.; Hasselmann, P. H.; Lazzaro, D.; Mothé-Diniz, T. (February 2010). "SDSS-based taxonomic classification and orbital distribution of main belt asteroids". Astronomy and Astrophysics. 510: 12. Bibcode:2010A&A...510A..43C. doi:10.1051/0004-6361/200913322. Retrieved 30 October 2019. (PDS data set)
    11. "Asteroid 4827 Dares". Small Bodies Data Ferret. Retrieved 21 June 2018.
    12. Waszczak, Adam; Chang, Chan-Kao; Ofek, Eran O.; Laher, Russ; Masci, Frank; Levitan, David; et al. (September 2015). "Asteroid Light Curves from the Palomar Transient Factory Survey: Rotation Periods and Phase Functions from Sparse Photometry". The Astronomical Journal. 150 (3): 35. arXiv:1504.04041. Bibcode:2015AJ....150...75W. doi:10.1088/0004-6256/150/3/75.
    13. "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 21 June 2018.

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