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 A Mars-crossing asteroid (MCA, also Mars-crosser, MC) is an asteroid whose orbit crosses that of Mars. Some Mars-crossers numbered below 100000 are listed here. They include the two numbered Mars trojans 5261 Eureka and . Many databases, for i ...

on an eccentric orbit from the

asteroid belt The asteroid belt is a torus-shaped region in the Solar System, located roughly between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies, of many sizes, but much smaller than planets, called ...

, approximately in diameter. It was discovered on 3 January 1997, by Japanese astronomer Takao Kobayashi 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 asteroid A Mars-crossing asteroid (MCA, also Mars-crosser, MC) is an asteroid whose orbit crosses that of Mars. Some Mars-crossers numbered below 100000 are listed here. They include the two numbered Mars trojans 5261 Eureka and . Many databases, for in ...

s, a dynamically unstable

group A group is a number of persons or things that are located, gathered, or classed together. Groups of people * Cultural group, a group whose members share the same cultural identity * Ethnic group, a group whose members share the same ethnic ide ...

between the

main belt The asteroid belt is a torus-shaped region in the Solar System, located roughly between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies, of many sizes, but much smaller than planets, called ...

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 Eccentricity or eccentric may refer to: * Eccentricity (behavior), odd behavior on the part of a person, as opposed to being "normal" Mathematics, science and technology Mathematics * Off-center, in geometry * Eccentricity (graph theory) of a v ...

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 ecliptic or ecliptic plane is the orbital plane of the Earth around the Sun. From the perspective of an observer on Earth, the Sun's movement around the celestial sphere over the course of a year traces out a path along the ecliptic again ...

. 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 Simeiz Observatory (also spelled Simeis or Simeïs) was an astronomy research observatory until the mid-1950s. It is located on Mount Koshka, Crimea, , by the town of Simeiz. Part of the Crimean Astrophysical Observatory, it is currently used f ...

in November 1940, or more than 56 years prior to its official discovery observation by Takao Kobayashi 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 Comet dust refers to cosmic dust that originates from a comet. Comet dust can provide clues to comets' origin. When the Earth passes through a comet dust trail, it can produce a meteor shower. Physical characteristics Size The majority of dus ...

. 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 In astronomy, a light curve is a graph of light intensity of a celestial object or region as a function of time, typically with the magnitude of light received on the y axis and with time on the x axis. The light is usually in a particular frequ ...

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 Magnitude may refer to: Mathematics *Euclidean vector, a quantity defined by both its magnitude and its direction *Magnitude (mathematics), the relative size of an object *Norm (mathematics), a term for the size or length of a vector *Order of ...

(). The result agrees with previous period determinations by Hungarian astronomers at

Konkoly Observatory Konkoly Observatory ( hu, Konkoly Thege Miklós Csillagászati Intézet; obs. code: 053) is an astronomical observatory located in Budapest, Hungary is part of the Research Centre for Astronomy and Earth Sciences ( hu, Csillagászati és ...

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 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, ...

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, 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