5331 Erimomisaki, provisional designation , is a background

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. ...

on an eccentric orbit from the central regions of 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 27 January 1990, by Japanese amateur astronomers

Kin Endate is a Japanese amateur astronomer who has discovered hundreds of asteroids, most of them in collaboration with Kazuro Watanabe, placing him among the most prolific discoverers of minor planets. Career in astronomy Kin Endate was born in Iwa ...

and

Kazuro Watanabe is a Japanese amateur astronomer and prolific discoverer of minor planets. He was born in Hokkaidō, Japan and is a member of the ''Astronomical Society of Japan'' as well as of the ''Oriental Astronomical Association''. Through publications ...

at the

Kitami Observatory Kitami Observatory is an astronomical observatory in the Kitami-Abashiri Region Cultural Centre in eastern Hokkaidō, Japan. Its observatory code is 400. It is 0.72344 Earth radii from the rotation axis and +0.68811 Earth radii from the equatorial ...

on Hokkaidō, Japan. The asteroid has a longer-than-average

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 24.26 hours. It was named after

Cape Erimo is a Cape (geography), cape in Hokkaidō, located at . It is the de facto southern tip of Hidaka Mountains. Description Hot and cold fronts meet near the cape, thus creating a dense mist which covers the cape for more than 100 days a year. Wi ...

at the southern tip of

Hokkaidō is Japan's second largest island and comprises the largest and northernmost prefecture, making up its own region. The Tsugaru Strait separates Hokkaidō from Honshu; the two islands are connected by the undersea railway Seikan Tunnel. The la ...

Orbit and classification

''Erimomisaki'' is a non-

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

asteroid from the main belt's background population. It orbits the Sun in the

central Central is an adjective usually referring to being in the center of some place or (mathematical) object. Central may also refer to: Directions and generalised locations * Central Africa, a region in the centre of Africa continent, also known as ...

main-belt at a distance of 1.7–3.8 AU once every 4 years and 7 months (1,678 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 2.76 AU). Its orbit has a relatively 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 0.39 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 12 ° 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

Crimea–Nauchnij The Crimean Astrophysical Observatory (CrAO, obs. code: 095) is located at Nauchnij research campus, near the Central Crimean city of Bakhchysarai, on the Crimean peninsula. CrAO is often called simply by its location and campus name, ...

in December 1984, more than 5 years prior to its official discovery observation at Kitami.

Physical characteristics

''Erimomisaki''

spectral type In astronomy, stellar classification is the classification of stars based on their stellar spectrum, spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a Prism (optics), prism or diffraction grati ...

is unknown. The ''Collaborative Asteroid Lightcurve Link'' (CALL) generically assumes it to be a carbonaceous

C-type asteroid C-type (carbonaceous) asteroids are the most common variety, forming around 75% of known asteroids. They are volatile-rich and distinguished by a very low albedo because their composition includes a large amount of carbon, in addition to rocks ...

(as its semi-major axis is larger than 2.7 AU). However, based on the body's albedo ''(see below)'', it is rather a stony

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 ...

Rotation period

In December 2007, two 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 ''Erimomisaki'' were obtained from photometric observations by international collaboration between astronomers

Silvano Casulli __NOTOC__ Vincenzo Silvano Casulli, usually known as Silvano Casulli (25 August 1944 – 24 July 2018

, Russel Durkee, Caleb Boe, Fiona Vincent and David Higgins. Lightcurve analysis gave a longer-than-average

of 24.233 and 24.26 hours with a brightness amplitude of 0.42 and 0.27

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 ...

, respectively (). CALL adopts the longer period as its best result. While not being a slow rotator, ''Erimomisaki'' period is longer than that of most other asteroids, which have spin rates between 2 and 20 hours.

Diameter and albedo

According to the surveys carried out by the Japanese Akari satellite and 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, ...

, ''Erimomisaki'' measures between 9.208 and 10.57 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 ...

between 0.2018 and 0.253. CALL generically assumes a carbonaceous albedo of 0.057 and consequently calculates a much larger diameter of 16.81 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 12.6.

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

( ja, Erimo-misaki) at the south end of

, Japan. The official naming citation 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 September 1993 ().

References

External links

Asteroid Lightcurve Database (LCDB)
query form

)
Dictionary of Minor Planet Names
Google books

– Observatoire de Genève, Raoul Behrend

– Minor Planet Center * * {{DEFAULTSORT:Erimomisaki 005331 Discoveries by Kin Endate Discoveries by Kazuro Watanabe Named minor planets 19900127