1310 Villigera

1310 Villigera, provisional designation 1932 DB, is a stony asteroid and large Mars-crosser from the innermost regions of the asteroid belt, approximately 14 kilometers in diameter. It was discovered on 28 February 1932, by German astronomer Friedrich Schwassmann at Bergedorf Observatory in Hamburg, Germany.[3] The asteroid was named after astronomer Walther Villiger.[2]

1310 Villigera
Modelled shape of Villigera from its lightcurve
Discovery [1]
Discovered byA. Schwassmann
Discovery siteBergedorf Obs.
Discovery date28 February 1932
Designations
(1310) Villigera
Named after
Walther Villiger
(Swiss astronomer)[2]
1932 DB · 1964 TC
Mars-crosser [1][3][4]
Orbital characteristics [1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc85.34 yr (31,171 days)
Aphelion3.2438 AU
Perihelion1.5424 AU
2.3931 AU
Eccentricity0.3555
3.70 yr (1,352 days)
76.690°
0° 15m 58.32s / day
Inclination21.071°
357.32°
88.759°
Physical characteristics
Dimensions13.76±1.38 km[5]
15.24 km (calculated)[4]
7.830±0.005 h[6][lower-alpha 1]
7.83001±0.00005 h[7]
7.834±0.001 h[8]
0.20 (assumed)[4]
0.245±0.049[5]
Tholen = S [1] · S [4]
B–V = 0.905[1]
U–B = 0.445[1]
11.45[1][4][5]

    Orbit and classification

    Villigera is a Mars-crossing asteroid, a dynamically unstable group between the main belt and the near-Earth populations, crossing the orbit of Mars at 1.666 AU. It orbits the Sun in the inner main-belt at a distance of 1.5–3.2 AU once every 3 years and 8 months (1,352 days). Its orbit has an eccentricity of 0.36 and an inclination of 21° with respect to the ecliptic.[1] No precoveries were taken, and no prior identifications were made. The body's observation arc begins 10 days after its official discovery observation with its first used observation at Uccle Observatory.[3]

    Physical characteristics

    Villigera is a common S-type asteroid on the Tholen taxonomic scheme.[1]

    Lightcurves

    In October 2001, a first rotational lightcurve of Villigera was obtained by astronomer Robert Koff at Thornton Observatory (713) in Colorado. Light curve analysis gave a well-defined rotation period of 7.830 hours with a brightness variation of 0.39 magnitude (U=3).[6][lower-alpha 1]

    Photometric observations by astronomers René Roy, Raoul Behrend and Pierre Antonini in February 2006, gave a concurring period of 7.834 hours and an amplitude of 0.36 magnitude (U=3).[8] In 2016, a modeled lightcurves using photometric data from various sources, rendered an identical period of 7.830 and a spin axis of (3.0°, 63°) in ecliptic coordinates.[7]

    Diameter and albedo

    According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Villigera measures 13.76 kilometers in diameter and its surface has an albedo of 0.245.[5] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 15.24 kilometers, with an absolute magnitude of 11.45.[4] Based on a generic magnitude-to-diameter conversion, Villigera measures between 13 and 30 kilometers for an albedo in the range of 0.05 to 0.25.[9]

    This makes Villigera one of the largest mid-sized Mars-crossing asteroids comparable with 1065 Amundsenia (9.75 km), 1139 Atami (9.35 km), 1474 Beira (8.73 km), 1011 Laodamia (7.5 km), 1727 Mette (est. 9 km), 1131 Porzia (7 km), 1235 Schorria (est. 9 km), 985 Rosina (8.18 km) and 1468 Zomba (7 km), but smaller than the largest members of this dynamical group, namely, 132 Aethra, 323 Brucia, 1508 Kemi, 2204 Lyyli and 512 Taurinensis, which are all larger than 20 kilometers in diameter.

    Naming

    This minor planet was named in honour of Swiss astronomer Walther Villiger (1872–1938), who himself discovered the main-belt asteroid 428 Monachia at Munich in 1897.[2] The official naming citation was also mentioned in The Names of the Minor Planets by Paul Herget in 1955 (H 120).[2]

    Notes
    1. Lightcurve plot of (1310) Villigera, Robert Koff, Thornton Observatory (713). Summary figures at LCDB
    gollark: Intel® 64 architecture delivers 64-bit computing on server, workstation, desktop and mobile platforms when combined with supporting software.¹ Intel 64 architecture improves performance by allowing systems to address more than 4 GB of both virtual and physical memory, however.
    gollark: They might be. If you flip all the belts and splitters.
    gollark: Oh, I got the direction wrong. Still valid.
    gollark: Well, balancers are symmetric maybe.
    gollark: 4 to 8 balancers are entirely valid.

    References
    1. "JPL Small-Body Database Browser: 1310 Villigera (1932 DB)" (2017-07-02 last obs.). Jet Propulsion Laboratory. Retrieved 25 July 2017.
    2. Schmadel, Lutz D. (2007). "(1310) Villigera". Dictionary of Minor Planet Names – (1310) Villigera. Springer Berlin Heidelberg. p. 107. doi:10.1007/978-3-540-29925-7_1311. ISBN 978-3-540-00238-3.
    3. "1310 Villigera (1932 DB)". Minor Planet Center. Retrieved 17 January 2017.
    4. "LCDB Data for (1310) Villigera". Asteroid Lightcurve Database (LCDB). Retrieved 17 January 2017.
    5. Alí-Lagoa, V.; Delbo', M. (July 2017). "Sizes and albedos of Mars-crossing asteroids from WISE/NEOWISE data" (PDF). Astronomy and Astrophysics. 603: 8. arXiv:1705.10263. Bibcode:2017A&A...603A..55A. doi:10.1051/0004-6361/201629917. Retrieved 20 October 2017.
    6. Koff, R. A. (June 2002). "Lightcurve Photometry of 492 Gismonda, 1046 Edwin, and 1310 Villigera". The Minor Planet Bulletin. 29: 25–26. Bibcode:2002MPBu...29...25K. Retrieved 17 January 2017.
    7. Hanus, J.; Durech, J.; Oszkiewicz, D. A.; Behrend, R.; Carry, B.; Delbo, M.; et al. (February 2016). "New and updated convex shape models of asteroids based on optical data from a large collaboration network". Astronomy and Astrophysics. 586: 24. arXiv:1510.07422. Bibcode:2016A&A...586A.108H. doi:10.1051/0004-6361/201527441.
    8. Behrend, Raoul. "Asteroids and comets rotation curves – (1310) Villigera". Geneva Observatory. Retrieved 17 January 2017.
    9. "Absolute Magnitude (H)". NASA/JPL. Retrieved 17 January 2017.

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