107 Camilla

Camilla (minor planet designation: 107 Camilla) is one of the largest asteroids from the outermost edge of the asteroid belt, approximately 250 kilometers (160 miles) in diameter. It is a member of the Sylvia family and located within the Cybele group. It was discovered on 17 November 1868, by English astronomer Norman Pogson at Madras Observatory, India, and named after Camilla, Queen of the Volsci in Roman mythology.[4][2] The X-type asteroid is a rare trinary asteroid with two minor-planet moons discovered in 2001 and 2016, respectively. It is elongated in shape and has a short rotation period of 4.8 hours.[18]

107 Camilla
Lightcurve-based 3-D model of Camilla
Discovery[1][2]
Discovered byN. R. Pogson
Discovery siteMadras Obs.
Discovery date17 November 1868
Designations
(107) Camilla
Pronunciation/kəˈmɪlə/[3]
Named after
Camilla (Roman mythology)[4]
A868 WA, 1893 QA
1938 OG, 1949 HD1
main-belt · (outer)[1]
Sylvia · Cybele
AdjectivesCamillian or Camillean, /kəˈmɪliən/
Orbital characteristics[1]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc149.17 yr (54,485 d)
Aphelion3.7202 AU
Perihelion3.2622 AU
3.4912 AU
Eccentricity0.0656
6.52 yr (2,383 d)
265.91°
0° 9m 3.96s / day
Inclination10.001°
172.61°
306.77°
Known satellites2[5][6][7]
Physical characteristics
Dimensions285 km × 205 km × 170 km[8]
344 km × 246 km × 205 km[9]
Mean diameter
254±12 km[10]
200.37±3.51 km[11]
210.370±8.326 km[12]
222.62±17.1 km[13]
241.6±35.0 km[14]
243.3±12.4 km[15]
Mass(11.2±0.1)×1018 kg[10][9]
Mean density
1.28±0.04 g/cm3[10]
1.40±0.30 g/cm3[9]
4.844 h[16][17][lower-alpha 1]
0.043±0.012[15]
0.045±0.019[14]
0.0525±0.009[13]
0.059±0.012[12]
0.065±0.003[11]
X (SMASS)[1][18]
C (Tholen)
P (WISE)[19]
B–V = 0.705[1]
U–B = 0.298[1]
11.53[20]
7.08[1][11][13][14][15][19]
7.1±0.02[18][21][16]

    Physical characteristics

    Camilla has a very dark surface and primitive carbonaceous composition.

    A large number of rotational lightcurves of have been obtained from photometric observations since the 1980s.[22] Best rated results gave a short rotation period of 4.844 hours with a brightness amplitude between 0.32 and 0.53 magnitude.[16][17][lower-alpha 1]

    Lightcurve analysis indicates that Camilla's pole most likely points towards ecliptic coordinates (β, λ) = (+51°, 72°) with a 10° uncertainty,[8] which gives it an axial tilt of 29°. Follow-up modeling of photometric data gave similar results.[23][24][25]

    Diameter and albedo

    10μ radiometric data collected from Kitt Peak in 1975 gave a first diameter estimate of 209 km.[26] According to the space-based surveys carried out by the Japanese Akari satellite, the Infrared Astronomical Satellite IRAS and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer,[11][12][13][19][21] as well as observations by the Keck Observatory and photometric modeling,[14][15][27][23][24][28][29] Camilla measures between 185 and 247 kilometers in diameter and its surface has an albedo between 0.160 and 0.294.[18]

    Satellites

    Camilla is the 6th trinary asteroid that has been discovered in the asteroid belt, after 87 Sylvia, 45 Eugenia, 216 Kleopatra, 93 Minerva and 130 Elektra (a quaternary).

    S1
    S/2001 (107) 1
    Discovery[6]
    Discovered byA. Storrs, F. Vilas,
    R. Landis, E. Wells,
    C. Woods, B. Zellner,
    and M. Gaffey
    Discovery date1 March 2001
    Orbital characteristics[10]
    Observation arc5642 days
    1247.8±1.3 km
    Eccentricity0.000±0.004
    3.71234±0.00001 d
    Inclination16.0°±0.8°
    Physical characteristics
    Mean diameter
    		12.7±3.5 km, assuming equal albedos and DCamilla = 254 km[10]
    16±6 km[9]
    ~ 11 ± 2 km[27]
    Mass~1.5×1015 kg[30]
    13.18[27]

      On 1 March 2001, a minor-planet moon of Camilla was found by A. Storrs, F. Vilas, R. Landis, E. Wells, C. Woods, B. Zellner, and M. Gaffey using the Hubble Space Telescope.[6] It has been designated S/2001 (107) 1 but has not yet received an official name.

      Later observations in September 2005 with the Very Large Telescope (VLT) allowed the determination of an orbit. Apart from data in infobox, the inclination was found to be 3 ± 1° with respect to an axis pointing towards (β, λ) = (+55°, 75°). Given the ~10° uncertainty in the actual rotational axis of Camilla, one can say that the orbit's inclination is less than 10°.

      The satellite is estimated to measure about 11 km in diameter.[27] Assuming a similar density to the primary, this would give it an approximate mass of ~1.5×1015 kg. It has a similar colour to the primary.[6]

      S2
      S/2016 (107) 1
      Discovery[7]
      Discovered byM. Marsset, B. Carry, B. Yang, F. Marchis, P. Vernazza, C. Dumas, J. Berthier, F. Vachier
      Discovery date2015 May 29
      Orbital characteristics[10]
      Observation arc428 days
      643.8±1.3 km
      Eccentricity0.18+0.08
      −0.06
      1.376±0.005 d
      Inclination27.7°±7.3°
      Satellite of107 Camilla
      Physical characteristics
      Mean diameter
      		4.0±1.2 km, assuming equal albedos and DCamilla = 254 km[10]

        In 2016, the discovery of a second satellite of Camilla was reported by astronomers at Cerro Paranal's Very Large Telescope in Chile. It has the provisional designation S/2016 (107) 1.[7]

        Observations were taken between 29 May 2015 and 30 July 2016, using the VLT-SPHERE, the principal instrument attached to the 8-meter "Melipal" (UT3) unit of the VLT. On 3 out of 5 observation sessions, the new satellite could be detected.[7] The body's orbit has a semi-major axis of 340 kilometers.[5]

        Notes
        1. Pietschnig (2011) web: Photometric observations from 28 March 2007. Rotation period 4.844±0.003 hours with a brightness amplitude of 0.47 magnitude. Quality code of 3. Summary figures at Collaborative Asteroid Lightcurve Link (CALL)

        References
        1. "JPL Small-Body Database Browser: 107 Camilla" (2018-02-07 last obs.). Jet Propulsion Laboratory. Retrieved 7 July 2018.
        2. "107 Camilla". Minor Planet Center. Retrieved 7 July 2018.
        3. Noah Webster (1884) A Practical Dictionary of the English Language
        4. Schmadel, Lutz D. (2007). "(107) Camilla". Dictionary of Minor Planet Names. Springer Berlin Heidelberg. p. 25. doi:10.1007/978-3-540-29925-7_108. ISBN 978-3-540-00238-3.
        5. Johnston, Robert (23 June 2015). "(107) Camilla, S/2001 (107) 1, and S/2016 (107) 1". johnstonsarchive.net. Retrieved 30 March 2017.
        6. IAUC 7599
        7. Marsset, M.; Carry, B.; Yang, B.; Marchis, F.; Vernazza, P.; Dumas, C.; et al. (August 2016). "S/2016 (107) 1". IAU Circ. 9282: 1. Bibcode:2016IAUC.9282....1M. Retrieved 30 March 2017.
        8. Torppa, Johanna; Kaasalainen, Mikko; Michalowski, Tadeusz; Kwiatkowski, Tomasz; Kryszczynska, Agnieszka; Denchev, Peter; et al. (August 2003). "Shapes and rotational properties of thirty asteroids from photometric data". Icarus. 164 (2): 346–383. Bibcode:2003Icar..164..346T. doi:10.1016/S0019-1035(03)00146-5. S2CID 119609765. Retrieved 30 March 2017.
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        30. Assuming a similar density to the primary.

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