1696 Nurmela, provisional designation , is a Baptistina
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 inner regions of the
asteroid belt, approximately in diameter. It was discovered on 18 March 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''; 16 ...
in Southwest Finland, and named after Finnish academician
Tauno Nurmela.
The possibly elongated asteroid 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 3.15 hours.
Orbit and classification
''Nurmela'' is the second-largest member of the small
Baptistina family
The Baptistina family (FIN: 403) is an asteroid family of more than 2500 members that was probably produced by the breakup of an asteroid across 80 million years ago following an impact with a smaller body. The two largest presumed remnants of ...
(), a large inner-belt family, named after
298 Baptistina
Baptistina (minor planet designation: 298 Baptistina) is an asteroid orbiting in the asteroid belt. It is the namesake of the Baptistina family. It was discovered on 9 September 1890 by Auguste Charlois of Nice. The source of its name is unkno ...
, its largest member and namesake.
When applying the
hierarchical clustering method to its
proper orbital elements
__NOTOC__
The proper orbital elements or proper elements of an orbit are constants of motion of an object in space that remain practically unchanged over an astronomically long timescale. The term is usually used to describe the three quantitie ...
, it is also a member of the
Flora family (),
a giant
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 ...
and the largest family of stony asteroids in the main-belt.
It orbits the Sun in the
inner
Interior may refer to:
Arts and media
* ''Interior'' (Degas) (also known as ''The Rape''), painting by Edgar Degas
* ''Interior'' (play), 1895 play by Belgian playwright Maurice Maeterlinck
* ''The Interior'' (novel), by Lisa See
* Interior de ...
main-belt at a distance of 2.0–2.5
AU once every 3 years and 5 months (1,242 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 2.26 AU). Its orbit has an
eccentricity of 0.10 and an
inclination of 6
° with respect to the
ecliptic.
The body's
observation arc begins with its official discovery observation at Turku.
Physical characteristics
''Nurmela'' is an assumed carbonaceous
C-type asteroid,
while its albedo and membership to the Baptistina family is indicative for an
X-type.
Rotation period
In March and April 2007, two rotational
lightcurves of ''Nurmela'' was obtained from photometric observations by
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 ...
and
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 ...
. They gave an identical
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 3.1587 hours with a brightness variation of 0.33 and 0.42
magnitude, respectively ().
In April 2017, another observation by Stephens gave a concurring period of 3.159 hours () with an amplitude of 0.58 magnitude, indicative for an elongated shape.
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, ''Nurmela'' measures between 6.06 and 10.31 kilometers in diameter and its surface has an
albedo between 0.116 and 0.28.
The ''Collaborative Asteroid Lightcurve Link'' assumes a standard albedo for carbonaceous asteroids of 0.057 and calculates a diameter of 14.64 kilometers based on an
absolute magnitude of 12.9.
Naming
This
minor planet was named in honor of Finnish academician Tauno Kalervo Nurmela (1907–1985), some time professor of Romanic philology and later chancellor of
University of Turku.
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 April 1980 ().
Notes
References
External links
Asteroid Lightcurve Database (LCDB) query form
)
Dictionary of Minor Planet Names Google books
– Observatoire de Geneve, Raoul Behrend
– Minor Planet Center
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{{DEFAULTSORT:Nurmela
001696
Discoveries by Yrjö Väisälä
Named minor planets
19390318