154 Bertha

154 Bertha
Discovery and designation
Discovered by P. M. Henry
Discovery date 1875
Designations
Main belt
Orbital characteristics[1]
Epoch August 27, 2011 (JD 2455800.5)
Aphelion 516.929 Gm (3.455 AU)
Perihelion 439.707 Gm (2.939 AU)
478.318 Gm (3.197 AU)
Eccentricity 0.081
2088.265 d (5.72 a)
16.63 km/s
178.804°
Inclination 21.043°
36.893°
155.936°
Physical characteristics
Dimensions 186.85 ± 1.83[2] km
Mass (9.19 ± 5.20) × 1018[2] kg
Mean density
 2.69 ± 1.52[2] g/cm3
Equatorial surface gravity
 0.0517 m/s²
Equatorial escape velocity
 0.0978 km/s
25.224[3] h
0.0483 ± 0.0107[4]
Temperature ~156 K
C[4]
7.530[4]

    154 Bertha is a main-belt asteroid. It was discovered by the French brothers Paul Henry and Prosper Henry on November 4, 1875, but the credit for the discovery was given to Prosper. It is probably named after Berthe Martin-Flammarion, sister of the astronomer Camille Flammarion.[5]

    Observations performed at the Palmer Divide Observatory in Colorado Springs, Colorado in during 2007 produced a light curve with a period of 22.30 ± 0.03 hours and a brightness range of 0.10 ± 0.02 in magnitude. A 1998 measurement gave a value of 27.6 hours, which doesn't fit the PDO data.[6] In 2011, observations from the Organ Mesa Observatory in Las Cruces, New Mexico were used to determine a rotation period of 25.224 ± 0.002 hours with a brightness variability of 0.10 ± 0.01 magnitude, ruling out previous studies.[3]

    This is classified as a C-type asteroid[4] and it has an estimated diameter of about 187 km.[2]

    References

    1. ↑ Yeomans, Donald K., "154 Bertha", JPL Small-Body Database Browser (NASA Jet Propulsion Laboratory), retrieved 2013-03-30.
    2. ↑ 2.0 2.1 2.2 2.3 Carry, B. (December 2012), "Density of asteroids", Planetary and Space Science 73: 98–118, arXiv:1203.4336, Bibcode:2012P&SS...73...98C, doi:10.1016/j.pss.2012.03.009. See Table 1.
    3. ↑ 3.0 3.1 Pilcher, Frederick (April 2012), "Rotation Period Determinations for 31 Euphrosyne, 65 Cybele, 154 Bertha 177 Irma, 200 Dynamene, 724 Hapag, 880 Herba, and 1470 Carla", Bulletin of the Minor Planets Section of the Association of Lunar and Planetary Observers 39 (2): 57–60, Bibcode:2012MPBu...39...57P.
    4. ↑ 4.0 4.1 4.2 4.3 Pravec, P. et al. (May 2012), "Absolute Magnitudes of Asteroids and a Revision of Asteroid Albedo Estimates from WISE Thermal Observations", Asteroids, Comets, Meteors 2012, Proceedings of the conference held May 16–20, 2012 in Niigata, Japan (1667), Bibcode:2012LPICo1667.6089P. See Table 4.
    5. ↑ Schmadel, Lutz D. (2012), Dictionary of Minor Planet Names (6th ed.), Springer, p. 27, ISBN 3642297188.
    6. ↑ Warner, Brian D. (September 2007), "Asteroid Lightcurve Analysis at the Palmer Divide Observatory", Bulletin of the Minor Planets Section of the Association of Lunar and Planetary Observers, Bibcode:2007MPBu...34...72W.