4587 Rees


4587 Rees, provisional designation , is a Mars-crosser and former near-Earth object on an eccentric orbit from the asteroid belt, approximately in diameter. It was discovered during the second Palomar–Leiden Trojan survey on 30 September 1973, by Dutch astronomer couple Ingrid and Cornelis van Houten at Leiden, and Tom Gehrels at the Palomar Observatory in California. The assumed S-type asteroid has a rotation period of 7.9 hours and is likely elongated in shape. It was named after British astrophysicist Martin Rees.

Orbit and classification

Rees is a Mars-crossing asteroid, a dynamically unstable group between the main belt and the near-Earth populations, crossing the orbit of Mars at 1.66 AU. It orbits the Sun at a distance of 1.31–4.01 AU once every 4 years and 4 months. Its orbit has a high eccentricity of 0.51 and an inclination of 25° with respect to the ecliptic. The body's observation arc begins with its first observation as at Palomar in September 1960, or 13 years prior to its official discovery observation.

Former near-Earth object

Before 2014, Rees has been a near-Earth object of the Amor group, as its perihelion was slightly less than 1.3 AU due to the body's osculating orbit.

Close approaches

In July 2072, Rees will pass from Mars, the closest since it passed from the Red Planet on 28 January 1843. The asteroid will also pass from the second largest asteroid, 4 Vesta, on 30 January 2121.

Palomar–Leiden Trojan survey

The survey designation "T-2" stands for the second Palomar–Leiden Trojan survey, named after the fruitful collaboration of the Palomar and Leiden Observatory in the 1960s and 1970s. Gehrels used Palomar's Samuel Oschin telescope, and shipped the photographic plates to Ingrid and Cornelis van Houten at Leiden Observatory where astrometry was carried out. The trio are credited with the discovery of :Category:Discoveries by the Palomar–Leiden survey|several thousand asteroid discoveries.

Naming

This minor planet was named after Martin Rees, a much awarded English cosmologist and astrophysicist who has studied the galactic evolution. Rees became Astronomer Royal and President of the Royal Society in 1995 and 2005, respectively. He is also the director of the Institute of Astronomy and a professor of astronomy at the University of Cambridge. The asteroid's name was proposed by Jan Oort, and the was published by the Minor Planet Center on 28 April 1991.

Physical characteristics

Rees is an assumed, stony S-type asteroid. Other sources published by EARN assume an Sr-subtype that transitions from the S-type to the rare R-type asteroids.

Rotation period

In May 2016, a rotational lightcurve of Rees was obtained from photometric observations by Robert Stephens at the Center for Solar System Studies in California. Lightcurve analysis gave a well-defined rotation period of hours with a brightness variation of 0.55 magnitude, indicative of an elongated, non-spheroidal shape. The result confirms previous observations by Czech astronomer Petr Pravec and by astronomers at the Palomar Transient Factory from April 2003 and October 2012, respectively.

Diameter and albedo

The Collaborative Asteroid Lightcurve Link assumes a standard albedo for an S-type asteroid of 0.20 and calculates a diameter of 2.03 kilometers based on an absolute magnitude of 15.87.