1534 Näsi, provisional designation , is a carbonaceous

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. ...

from the middle region of the asteroid belt, approximately 20 kilometers in diameter. It was discovered on 20 January 1939, by Finnish astronomer Yrjö Väisälä at

Turku Observatory Turku ( ; ; sv, Åbo, ) is a city and former capital on the southwest coast of Finland at the mouth of the Aura River, in the region of Finland Proper (''Varsinais-Suomi'') and the former Turku and Pori Province (''Turun ja Porin lääni''; ...

in Southwest Finland, and later named for the Finnish lake Näsijärvi.

Orbit and classification

''Näsi'' 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 2.0–3.4 AU once every 4 years and 6 months (1,646 days). Its orbit has an eccentricity of 0.25 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 10 ° with respect to the ecliptic. It was first identified as at Simeiz Observatory in 1915. 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 15 years prior to its official discovery with its identification as at

Heidelberg Observatory Heidelberg (; Palatine German: ') is a city in the German state of Baden-Württemberg, situated on the river Neckar in south-west Germany. As of the 2016 census, its population was 159,914, of which roughly a quarter consisted of students. ...

Physical characteristics

Lightcurve observations

In April 2007, the so-far best rated rotational lightcurve of ''Näsi'' was obtained by Jason Sauppe at Oakley Observatory in the United States. The lightcurve analysis gave 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 7.94 hours with a brightness variation of 0.35 magnitude (). Periods from other photometric observations were obtained by astronomers René Roy in May 2016 (5.98 hours, Δ0.47 mag, ),

Giovanni de Sanctis Giovanni de Sanctis (born 1949) is an Italian astronomer and discoverer of minor planets at the Osservatorio Astronomico di Torino (Astronomical Observatory of Turin) in Turin, Italy. His name is sometimes spelt DeSanctis, particularly in the Mi ...

in the 1990s (9.75 hours, Δ0.22 mag, ),

Adrián Galád Adrián Galád (born 1970) is a Slovak astronomer and a discoverer of minor planets. He is credited by the Minor Planet Center with the discovery and co-discovery of 81 numbered minor planets between 1995 and 2009, most of them in collaboratio ...

in October 2005 (7.9338 hours, Δ0.51 mag, ), and a period of 7.93161 hours modeled from various data sources and published in 2016 ().

Spectral type, diameter and albedo

In the SMASS taxonomy, the carbonaceous C-type asteroid is also classified as a Cgh-subtype. According to the surveys 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 ...

, the Japanese Akari satellite, and 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, ...

with its subsequent NEOWISE mission, ''Näsi'' measures between 18.32 and 27.52 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 0.035 and 0.100. The ''Collaborative Asteroid Lightcurve Link'' derives an albedo of 0.0721 and a diameter of 22.11 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 11.75.

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 ...

is named for the large Finnish lake Näsijärvi, sometimes called "Näsi". It measures 256 square kilometers (99 sq mi) in size and is located only 95 metres above sea level. 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 20 February 1976 ().

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:Nasi 001534 Discoveries by Yrjö Väisälä Named minor planets 001534 19390120