4035 Thestor


4035 Thestor, provisional designation: 1986 WD, is a large Jupiter trojan from the Greek camp, approximately in diameter. It was discovered on 22 November 1986, by Japanese astronomers Kenzo Suzuki and Takeshi Urata at the Toyota Observatory in Toyota, Japan. The assumed C-type asteroid belongs to the [|50 largest Jupiter trojans] and has a rotation period of 13.5 hours. Of more than half a million numbered minor planets, it has been the second-lowest numbered body without a name, until May 2021, when it was named after Thestor, a grandson of Apollo from Greek mythology.

Classification and orbit

Thestor is a dark Jovian asteroid orbiting in the leading Greek camp at Jupiter's Lagrangian point, 60° ahead of the Gas Giant's orbit in a 1:1 resonance '. It is also a non-family asteroid in the Jovian background population.
It orbits the Sun at a distance of 5.0–5.6 AU once every 12 years and 2 months. Its orbit has an eccentricity of 0.06 and an inclination of 12° with respect to the ecliptic. The body's observation arc begins with its first observation as ' at Crimea–Nauchnij in September 1973, or 13 years prior to its official discovery observation at Toyota, Japan.

Numbering and naming

This minor planet was numbered by the Minor Planet Center on 22 March 1989. On 14 May 2021, the object was named by the Working Group for Small Bodies Nomenclature, after Thestor from Greek mythology, who was a grandson of Apollo and the father of Calchas.
Before Thestor was named, it belonged to a small group of only 8 unnamed minor planets with a designated number smaller than 5000.. Since then, several have already been named:
Thestor is an assumed, carbonaceous C-type asteroid, which is in line with the body's albedo , while its V–I color index of 0.93 agrees with that of most Jovian D-type asteroids.

Rotation period

In October 2009, a rotational lightcurve was obtained from photometric observations by astronomer Stefano Mottola at the Calar Alto Observatory in Spain. It gave a well-defined rotation period of hours with a brightness variation of 0.21 in magnitude, superseding a period of 13.52 hours and an amplitude of more than 0.20 previously measured with the ESO 1-metre telescope at La Silla Observatory in May 1991.
In August 2015, photometric observations of Thestor by the Kepler space observatory during its K2 mission gave a concurring period of 13.475 and 13.49 hours with a brightness amplitude of 0.18 and 0.17 magnitude observations.

Diameter and albedo

According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite, and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, the asteroid measures between 66.99 and 68.73 kilometers in diameter and its surface has an albedo between 0.054 and 0.076. The Collaborative Asteroid Lightcurve Link derives an albedo of 0.0548 and a diameter of 68.23 kilometers based on an absolute magnitude of 9.6.