1494 Savo, provisional designation , is a stony 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.
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from the inner region of the asteroid belt, approximately 8 kilometers in diameter. Discovered by astronomer Yrjö Väisälä at the
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''; 16 ...
in 1938, the asteroid was later named after the Finnish region of Savonia.
Discovery
''Savo'' was discovered on 16 September 1938, by Finnish astronomer Yrjö Väisälä at the
Iso-Heikkilä Observatory
Iso-Heikkilä Observatory ( fi, Iso-Heikkilän tähtitorni, sv, Storheikkilä observatorium) is an amateur astronomical observatory used by a local amateur astronomical association, Turun Ursa ry in the Iso-Heikkilä district of Turku, Finl ...
near Turku, Finland. Two nights later, it was independently discovered by German astronomer
Arno Arthur Wachmann
Arno Arthur Wachmann (8 March 1902 – 24 July 1990) was a German astronomer and discoverer of comets and minor planets, who worked for many years at the Bergedorf Observatory in Hamburg.Bergedorf Observatory in Hamburg. However, 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
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only acknowledges the first discoverer. The asteroid was first identified as at the Crimean Simeiz Observatory in September 1929, or nine years before its official discovery observation.
Orbit and classification
''Savo'' is an asteroid of the main belt's background population that does not belong to any known
asteroid family
An asteroid family is a population of asteroids that share similar proper orbital elements, such as semimajor axis, eccentricity, and orbital inclination. The members of the families are thought to be fragments of past asteroid collisions. An a ...
. It orbits the Sun in the
inner
Interior may refer to:
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* ''Interior'' (Degas) (also known as ''The Rape''), painting by Edgar Degas
* ''Interior'' (play), 1895 play by Belgian playwright Maurice Maeterlinck
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* Interior de ...
asteroid belt at a distance of 1.9–2.5 AU once every 3 years and 3 months (1,184 days). Its orbit has an eccentricity of 0.13 and an inclination of 2 ° with respect to the ecliptic. The body's observation arc begins with its official discovery observation at Turku in September 1938.
Physical characteristics
In the
SMASS classification
An asteroid spectral type is assigned to asteroids based on their emission spectrum, color, and sometimes albedo. These types are thought to correspond to an asteroid's surface composition. For small bodies that are not internally differentiat ...
, ''Savo'' is an Sa-subtype that transitions from the stony S-type to the
A-type asteroid A-type asteroids are relatively uncommon inner-belt asteroids that have a strong, broad 1 micrometre, μm olivine feature and a very reddish spectrum shortwards of 0.7 μm. They are thought to come from the completely differentiated Mantle (geo ...
s.
Rotation period
In August 2006, a rotational lightcurve of ''Savo'' was obtained from photometric observations by Czech astronomer Petr Pravec at
Ondřejov Observatory
The Ondřejov Observatory (; cs, Observatoř Ondřejov) is the principal observatory of the Astronomical Institute () of the Academy of Sciences of the Czech Republic. It is located near the village of Ondřejov, southeast of Prague, Czech R ...
. Lightcurve analysis gave a well-defined
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 5.35011 hours with a brightness amplitude of 0.52 magnitude (), indicative for a non-spherical shape. Follow up observations at the Calvin College Observatory () in 2007 and 2008, gave three nearly identical periods of 5.35020, 5.35031 and 5.35062 hours with an amplitude between 0.44 and 0.63 ().
Poles
The asteroid's lightcurve has also been modeled twice. In 2011, the first modelling used photometric data from the AstDyS database and the Uppsala Asteroid Photometric Catalogue, and found two spin axis of (248.0°, −68.0°) and (83.0°, −66.0°) in ecliptic coordinates (λ, β). A refined modeling in 2016, using the ''Lowell Photometric Database'' gave two poles of (50.0°, −65.0°) and (233.0°, −68.0°) in ecliptic coordinates. Also, both studies found a concurring period of 5.35059 hours.
Diameter and albedo
According to the surveys carried out by the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, ''Savo'' measures between 7.80 and 9.23 kilometers in diameter and its surface has an albedo between 0.173 and 0.349. The ''Collaborative Asteroid Lightcurve Link'' assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 10.30 kilometers based on an absolute magnitude of 12.3.
Naming
This minor planet was named after Finnish historical province of Savonia. 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
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