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42 Isis

A three-dimensional model of 42 Isis based on its light curve
Discovery
Discovered by	Norman Robert Pogson
Discovery date	23 May 1856
Designations
MPC designation	(42) Isis
Pronunciation	/ˈaɪsɪs/
Named after	Isis Pogson
Minor planet category	Main belt
Adjectives	Isidian /aɪˈsɪdiən/
Orbital characteristics
Epoch 31 December 2006 (JD 2454100.5)
Aphelion	446.706 Gm (2.986 AU)
Perihelion	283.890 Gm (1.898 AU)
Semi-major axis	365.298 Gm (2.442 AU)
Eccentricity	0.223
Orbital period (sidereal)	1393.737 d (3.82 a)
Mean anomaly	121.874°
Inclination	8.530°
Longitude of ascending node	84.398°
Time of perihelion	2024-Oct-17
Argument of perihelion	236.626°
Physical characteristics
Dimensions	102.73±2.73 km
Mass	(1.58±0.52)×10 kg
Mean density	2.78±0.93 g/cm
Synodic rotation period	13.59701 h
Geometric albedo	0.171 (geometric)
Spectral type	S
Apparent magnitude	9.18 to 13.50
Absolute magnitude (H)	7.53

42 Isis is a large main-belt asteroid, measuring 100.2 km in diameter with a stony (S-type) composition. It was discovered by English astronomer N.R. Pogson on 23 May 1856 at Oxford, and was his first asteroid discovery. The asteroid's name was chosen by Manuel John Johnson, director of the Radcliffe Observatory in Oxford. Although Isis is the name of an Egyptian goddess, the name was chosen in homage to Pogson's astronomer daughter, (Elizabeth) Isis Pogson. In addition, the Isis is the stretch of the River Thames that runs through Oxford.

This asteroid is orbiting the Sun with a period of 3.82 years. The light curve inversion technique, when applied to photometric observations of this asteroid, show multiple local irregularities. The overall shape displays little elongation, with a ratio between the major and minor axes equal to 1.1. The measured rotation period for this model is 13.6 hours. The spectrum of 42 Isis reveals the strong presence of the mineral Olivine, a relative rarity in the asteroid belt.

References

1. Noah Webster (1884) A Practical Dictionary of the English Language
2. E.g. Adriano La Regina ed. (2004) Archaeological Guide to Rome, p. 66. Cf. the pronunciation of "isidium". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.).
3. ^ Carry, B. (December 2012), "Density of asteroids", Planetary and Space Science, 73 (1): 98–118, arXiv:1203.4336, Bibcode:2012P&SS...73...98C, doi:10.1016/j.pss.2012.03.009, S2CID 119226456. See Table 1.
4. ^ Torppa, Johanna; 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.
5. Asteroid Data Sets Archived 17 December 2009 at the Wayback Machine
6. "AstDys (42) Isis Ephemerides". Department of Mathematics, University of Pisa, Italy. Archived from the original on 27 March 2012. Retrieved 27 June 2010.
7. Bruck, Mary (2009), Women in Early British and Irish Astronomy, Springer, p. 157, ISBN 978-90-481-2472-5.
8. Lutz D. Schmadel (2011). Dictionary of Minor Planet Names (Addendum to Fifth Edition: 2006–2008 ed.). Springer. ISBN 978-3-642-01966-1.
9. Burbine, T. H.; et al. (July 2000), "The Nature of Olivine Asteroids", Meteoritics & Planetary Science, vol. 35, pp. A35, Bibcode:2000M&PSA..35R..35B, doi:10.1111/j.1945-5100.2000.tb01796.x.

External links

• 42 Isis at AstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 42 Isis at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit viewer · Orbit parameters · Physical parameters

• Minor planet object articles (numbered)
• S-type asteroids (Tholen)
• L-type asteroids (SMASS)
• Background asteroids
• Discoveries by N. R. Pogson
• Named minor planets
• Astronomical objects discovered in 1856