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13963 Euphrates (/juːˈfreɪtiːz/), provisional designation 1991 PT₄, is a resonant Griqua asteroid from the outer region of the asteroid belt, approximately 9 kilometers in diameter. It was discovered on 3 August 1991, by Belgian astronomer Eric Elst at ESO's La Silla Observatory site in Chile. The asteroid was named after the Euphrates River in the Middle East.

Orbit and classification

Euphrates is one of very few bodies located in the 2:1 mean motion resonance with the gas giant Jupiter and belongs to the "marginally unstable" Griqua group.

It orbits the Sun in the outer main-belt at a distance of 2.5–4.2 AU once every 6 years and 1 month (2,220 days). Its orbit has an eccentricity of 0.26 and an inclination of 1° with respect to the ecliptic. A first precovery was taken at Palomar Observatory in 1971, extending the asteroid's observation arc by 20 years prior to its official discovery observation.

Physical characteristics

Based on an absolute magnitude of 13.9, it measures between 4 and 10 kilometers in diameter, assuming an albedo in the range of 0.05 to 0.25. Since asteroids in the outer main-belt are mostly of a carbonaceous rather than of a silicaceous composition, with low albedos, typically around 0.06, its diameter is likely to be between 8 and 10 kilometers.

As of 2017, Euphrates' effective size, its composition and albedo, as well as its rotation period and shape remain unknown.

Naming

This minor planet was named after the Euphrates river, that flows through northern Syria and Iraq.

It is one of the most historically important rivers of Western Asia. The Tigris–Euphrates river system, a major river system, is formed when the two rivers combine at Al Qurnah. The minor planet 13096 Tigris is named after the other river of this system. The approved naming citation was published by the Minor Planet Center on 6 August 2003 (M.P.C. 49280).

References

1. ^ "JPL Small-Body Database Browser: 13963 Euphrates (1991 PT4)" (2017-03-17 last obs.). Jet Propulsion Laboratory. Retrieved 5 July 2017.
2. ^ Schmadel, Lutz D. (2006). "(13963) Euphrates ". Dictionary of Minor Planet Names – (13963) Euphrates, Addendum to Fifth Edition: 2003–2005. Springer Berlin Heidelberg. p. 82. doi:10.1007/978-3-540-34361-5_818. ISBN 978-3-540-34360-8.
3. ^ Roig, F.; Nesvorný, D.; Ferraz-Mello, S. (September 2002). "Asteroids in the 2 : 1 resonance with Jupiter: dynamics and size distribution". Monthly Notices of the Royal Astronomical Society. 335 (2): 417–431. Bibcode:2002MNRAS.335..417R. doi:10.1046/j.1365-8711.2002.05635.x.
4. ^ "Absolute Magnitude (H)". NASA/JPL. Archived from the original on 2 March 2001. Retrieved 7 April 2016.
5. ^ "13963 Euphrates (1991 PT4)". Minor Planet Center. Retrieved 7 April 2016.
6. "LCDB Data for (13963) Euphrates". Asteroid Lightcurve Database (LCDB). Retrieved 5 July 2017.
7. "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 19 May 2016.

External links

• (13963) Euphrates at AstDyS, University of Pisa
• Asteroid Lightcurve Database (LCDB), query form (info Archived 16 December 2017 at the Wayback Machine)
• Dictionary of Minor Planet Names, Google books
• Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend
• Discovery Circumstances: Numbered Minor Planets (10001)-(15000) – Minor Planet Center
• 13963 Euphrates at AstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 13963 Euphrates at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit viewer · Orbit parameters · Physical parameters

• Minor planet object articles (numbered)
• Griqua asteroids
• Discoveries by Eric Walter Elst
• Named minor planets
• Astronomical objects discovered in 1991