444 Gyptis

Gyptis, minor planet designation: 444 Gyptis, is a main-belt asteroid that was discovered by J. Coggia on March 31, 1899, in Marseilles. It is classified as a C-type asteroid and is probably composed of carbonaceous material. The spectra of the asteroid displays evidence of aqueous alteration.[4]

444 Gyptis
Discovery
Discovered byJ. Coggia
Discovery date31 March 1899
Designations
(444) Gyptis
Pronunciation/ˈdʒɪptɪs/
Named after
Gyptis
1899 EL
Main belt
AdjectivesGyptidian
Orbital characteristics[1]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc116.54 yr (42568 d)
Aphelion3.25674 AU (487.201 Gm)
Perihelion2.28337 AU (341.587 Gm)
2.77005 AU (414.394 Gm)
Eccentricity0.17569
4.61 yr (1684.0 d)
11.8852°
0° 12m 49.615s / day
Inclination10.2775°
195.716°
154.984°
Physical characteristics
Dimensions179×150 km[2]
163.08±10.0 km[1]
Mass1.25×1019 kg[3]
Mean density
5.53±1.46 g/cm3[3]
6.214 h (0.2589 d)[1]
0.0490±0.007[1]
C[1]
7.83[1]

    In 2004, Kochetova estimated Gyptis to have a mass of 1.25×1019 kg with a high density of 5.53 g/cm3.[3] The adaptive optics instrument at the W. M. Keck Observatory showed an object with a diameter of 129 km, which is much smaller than the estimate of 160 km from the IRAS observatory measurements, indicating an irregular shape. The size ratio between the major and minor axes is estimated at 1.40.[5] Observations of an occultation on October 14, 2007, produced six chords indicating a cross-section ellipsoid of 179×150 km.[2]

    Between 1990 and 2021, 444 Gyptis has been observed to occult 17 stars.

    References
    1. "JPL Small-Body Database Browser: 444 Gyptis (1899 EL)" (2008-11-01 last obs). Retrieved 10 May 2016.
    2. "2007 European Asteroidal Occultation Results". euraster.net (a website for Asteroidal Occultation Observers in Europe). 14 October 2007. Retrieved 1 December 2008. (Chords)
    3. Jim Baer (2008). "Recent Asteroid Mass Determinations". Personal Website. Archived from the original on 2 July 2013. Retrieved 27 November 2008.
    4. Fornasier, S.; et al. (February 1999), "Spectroscopic comparison of aqueous altered asteroids with CM2 carbonaceous chondrite meteorites", Astronomy and Astrophysics Supplement, 135: 65−73, Bibcode:1999A&AS..135...65F, doi:10.1051/aas:1999161.
    5. Marchis, F.; et al. (November 2006), "Shape, size and multiplicity of main-belt asteroids. I. Keck Adaptive Optics survey", Icarus, 185 (1): 39–63, Bibcode:2006Icar..185...39M, doi:10.1016/j.icarus.2006.06.001, PMC 2600456, PMID 19081813.

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