7505 Furusho, provisional designation , is a stony

asteroid An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere. ...

and sizable Mars-crosser on an eccentric orbit from the asteroid belt, approximately in diameter. It was discovered on 3 January 1997, by Japanese astronomer

Takao Kobayashi is a Japanese amateur astronomer and an outstanding discoverer of minor planets who currently works at the Ōizumi Observatory. The asteroid 3500 Kobayashi is named after him. Career Kobayashi has discovered more than 2000 asteroids using ...

at the Ōizumi Observatory in the Kantō region of Japan. The assumed

S-type asteroid S-type asteroids are asteroids with a spectral type that is indicative of a siliceous (i.e. stony) mineralogical composition, hence the name. They have relatively high density. Approximately 17% of asteroids are of this type, making it the second ...

is likely elongated in shape and has a

rotation period The rotation period of a celestial object (e.g., star, gas giant, planet, moon, asteroid) may refer to its sidereal rotation period, i.e. the time that the object takes to complete a single revolution around its axis of rotation relative to the ...

of 4.1 hours. It was named for Japanese astronomer .

Orbit and classification

''Furusho'' is a member of the Mars-crossing asteroids, a dynamically unstable group between the main belt and the near-Earth populations, crossing the orbit of

Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury (planet), Mercury. In the English language, Mars is named for the Mars (mythology), Roman god of war. Mars is a terr ...

at 1.66 AU. It orbits the Sun at a distance of 1.6–3.6 AU once every 4 years and 3 months (1,563 days;

semi-major axis In geometry, the major axis of an ellipse is its longest diameter: a line segment that runs through the center and both foci, with ends at the two most widely separated points of the perimeter. The semi-major axis (major semiaxis) is the long ...

of 2.64 AU). Its orbit has a high eccentricity of 0.38 and an

inclination Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a Plane of reference, reference plane and the orbital plane or Axis of rotation, axis of direction of the orbiting object ...

of 6 ° with respect to the ecliptic. The body's

observation arc In observational astronomy, the observation arc (or arc length) of a Solar System body is the time period between its earliest and latest observations, used for tracing the body's path. It is usually given in days or years. The term is mostly use ...

begins with its first observation as at the Crimean Simeiz Observatory in November 1940, or more than 56 years prior to its official discovery observation by

at Ōizumi in January 1997.

Naming

This

minor planet According to the International Astronomical Union (IAU), a minor planet is an astronomical object in direct orbit around the Sun that is exclusively classified as neither a planet nor a comet. Before 2006, the IAU officially used the term ''minor ...

was named after Japanese astronomer Reiko Furusho (born 1970). Her research includes

comet A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena ar ...

ary physics, in particular the measurement of polarized light, caused by scattering on comet dust. Furusho also works in the education and popularization of astronomy. The official was published by the

Minor Planet Center The Minor Planet Center (MPC) is the official body for observing and reporting on minor planets under the auspices of the International Astronomical Union (IAU). Founded in 1947, it operates at the Smithsonian Astrophysical Observatory. Function ...

on 1 May 2003 ().

Physical characteristics

''Furusho'' is an assumed

Rotation period

In November 2017, a rotational lightcurve of ''Furusho'' was obtained from photometric observations by Daniel Klinglesmith at Etscorn Observatory in Socorro, New Mexico. Lightcurve analysis gave a well-defined

of hours with a high brightness variation of 0.63 magnitude (). The result agrees with previous period determinations by Hungarian astronomers at Konkoly Observatory in autumn 2001 (), and with observations by astronomers at the

Palomar Transient Factory The Palomar Transient Factory (PTF, obs. code: I41), was an astronomical survey using a wide-field survey camera designed to search for optical transient and variable sources such as variable stars, supernovae, asteroids and comets. The projec ...

in California in May 2011 ().

Robert Stephens Sir Robert Graham Stephens (14 July 193112 November 1995) was a leading English actor in the early years of Britain's Royal National Theatre. He was one of the most respected actors of his generation and was at one time regarded as the natur ...

at Santana Observatory and Brian Warner at the Palmer Divide Station also determined an identical period in November 2001 and December 2013, respectively (). All observations showed a classically shaped bimodal lightcurve with a high brightness amplitude between 0.52 and 0.75 magnitude, which is indicative of an elongated, non-spherical shape.

Diameter and albedo

According to the survey carried out by the Infrared Astronomical Satellite

IRAS The Infrared Astronomical Satellite (Dutch: ''Infrarood Astronomische Satelliet'') (IRAS) was the first space telescope to perform a survey of the entire night sky at infrared wavelengths. Launched on 25 January 1983, its mission lasted ten mo ...

, ''Furusho'' measures 9.07 kilometers in diameter and its surface has an

albedo Albedo (; ) is the measure of the diffuse reflection of sunlight, solar radiation out of the total solar radiation and measured on a scale from 0, corresponding to a black body that absorbs all incident radiation, to 1, corresponding to a body ...

of 0.37. In 2017, a study dedicated to Mars-crossing asteroids by the NEOWISE mission of NASA's

Wide-field Infrared Survey Explorer Wide-field Infrared Survey Explorer (WISE, observatory code C51, Explorer 92 and SMEX-6) is a NASA infrared astronomy space telescope in the Explorers Program. It was launched in December 2009, and placed in hibernation mode in February 2011, ...

determined a diameter of 10.04 kilometers with an albedo of 0.21. The ''Collaborative Asteroid Lightcurve Link'' derives an albedo of 0.29 and a diameter of 8.9 kilometers based on an

absolute magnitude Absolute magnitude () is a measure of the luminosity of a celestial object on an inverse Logarithmic scale, logarithmic Magnitude (astronomy), astronomical magnitude scale. An object's absolute magnitude is defined to be equal to the apparent mag ...

of 12.20.

Sizable Mars-crosser

With a diameter of 10 kilometers, ''Furusho'' is a typical "sizable" Mars-crosser (5–15 km) of which two dozens or so are known. These include 3581 Alvarez (13.7 km) 1065 Amundsenia (9.8 km), 1139 Atami (9.4 km), 3737 Beckman (14.4 km), 1474 Beira (15.5 km), 5682 Beresford (7.3 km), 7369 Gavrilin (5.5 km), 1011 Laodamia (7.4 km), 6170 Levasseur (5.7 km), 1727 Mette (5.4 km), 1131 Porzia (7.1 km), 985 Rosina (8.2 km), 1235 Schorria (5.6 km), 1310 Villigera (15.2 km), and 1468 Zomba (7 km), which are themselves smaller than the largest members of this dynamical group, namely,

132 Aethra Aethra (minor planet designation: 132 Aethra) is a metallic asteroid and Mars-crosser on an eccentric orbit from the asteroid belt. It measures approximately 40 kilometers in diameter. It was discovered by James Craig Watson in 1873 and is the ...

, 323 Brucia (former Mars-crosser), 1508 Kemi, 2204 Lyyli and 512 Taurinensis, all larger than 20 kilometers.

Orbit and classification

Naming

Physical characteristics

Rotation period

Diameter and albedo

Sizable Mars-crosser

Notes

References

External links