1252 Celestia, provisional designation , is a stony

asteroid An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the Solar System#Inner Solar System, inner Solar System or is co-orbital with Jupiter (Trojan asteroids). As ...

located in the central

asteroid belt The asteroid belt is a torus-shaped region in the Solar System, centered on the Sun and roughly spanning the space between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies called asteroids ...

. It was discovered on 19 February 1933, by astronomer

Fred Whipple Fred Lawrence Whipple (November 5, 1906 – August 30, 2004) was an American astronomer, who worked at the Harvard College Observatory for more than 70 years. Among his achievements were asteroid and comet discoveries, the " dirty snowball" hy ...

at the

Oak Ridge Observatory The Oak Ridge Observatory (ORO, code: 801), also known as the George R. Agassiz Station, is located at 42 Pinnacle Road, Harvard, Massachusetts. It was operated by the Center for Astrophysics Harvard & Smithsonian as a facility of the Smit ...

operated by the Harvard-Smithsonian Center for Astrophysics in Massachusetts, United States. The

S-type asteroid S-type (stony-type or silicaceous-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 ...

has a

rotation period In astronomy, the rotation period or spin period of a celestial object (e.g., star, planet, moon, asteroid) has two definitions. The first one corresponds to the '' sidereal rotation period'' (or ''sidereal day''), i.e., the time that the objec ...

of 10.6 hours and measures approximately in diameter. It was named after the discoverer's mother, Celestia MacFarland Whipple.

Orbit and classification

According to a synthetic HCM-analysis by Nesvorný, ''Celestia'' is a member of the

Pallas family The Pallas family (''adj. Palladian''; ) is a small asteroid family of B-type asteroids at very high Orbital inclination, inclinations in the intermediate asteroid belt. The family was identified by Kiyotsugu Hirayama in 1928. The namesake of the ...

(), a small

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 ...

of less than 200 known members with inclined orbits. The family is named after 2 Pallas. However, in a HCM-analysis by Milani and

Knežević Knežević () is a Serbian, Croatian, Montenegrin and Bosnian surname, derived from the title of '' knez''. It may refer to: * House of Knežević, Croatian noble family Knežević is the eighth most frequent surname in Croatia. The angliciz ...

, ''Celestia'' belongs to the background population. The asteroid orbits the Sun in the central main-belt at a distance of 2.1–3.3 AU once every 4 years and 5 months (1,615 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 longe ...

of 2.69 AU). Its orbit has an

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-Centre (geometry), center, in geometry * Eccentricity (g ...

of 0.21 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 reference plane and the orbital plane or axis of direction of the orbiting object. For a satellite orbiting the Eart ...

of 34 ° with respect to the

ecliptic The ecliptic or ecliptic plane is the orbital plane of Earth's orbit, Earth around the Sun. It was a central concept in a number of ancient sciences, providing the framework for key measurements in astronomy, astrology and calendar-making. Fr ...

. 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 at the

Yerkes Observatory Yerkes Observatory ( ) is an astronomical observatory located in Williams Bay, Wisconsin, United States. The observatory was operated by the University of Chicago Department of Astronomy and Astrophysics from its founding in 1897 until 2018. O ...

in April 1933, or two months after its official discovery observation at Oak Ridge.

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 the mother of the discoverer, Celestia MacFarland Whipple. The official was mentioned in ''

The Names of the Minor Planets Paul Herget (January 30, 1908 – August 27, 1981) was an American astronomer and director of the Cincinnati Observatory, who established the Minor Planet Center after World War II. Career Herget taught astronomy at the University of Cincinna ...

'' by

Paul Herget Paul Herget (January 30, 1908 – August 27, 1981) was an American astronomer and director of the Cincinnati Observatory, who established the Minor Planet Center after World War II. Career Herget taught astronomy at the University of Cincinna ...

in 1955 ().

Physical characteristics

In the

Tholen Tholen () is a 25,000 people municipality in the southwest of the Netherlands. The municipality of Tholen takes its name from the town of Tholen, which is the largest population center in the municipality. The municipality consists of two peninsu ...

and

SMASS classification An asteroid spectral type is assigned to asteroids based on their reflectance spectrum, color, and sometimes albedo. These types are thought to correspond to an asteroid's surface composition. For small bodies that are not internally different ...

, ''Celestia'' is a common stony

, while in SMASS-like taxonomy of the Small Solar System Objects Spectroscopic Survey (S3OS2), it is a Sl-subtype that transitions from the S-type to the

L-type asteroid L-type asteroids are relatively uncommon asteroids with a strongly reddish spectrum shortwards of 0.75 μm, and a featureless flat spectrum longwards of this. In comparison with the K-type, they exhibit a more reddish spectrum at visible wavelen ...

s. ''Celestia'' stony

spectral type In astronomy, stellar classification is the classification of stars based on their spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a prism or diffraction grating into a spectrum exhibiting the ...

does not agree with those determined for the members of the Pallas family, which are typically "bright" carbonaceous

B-type asteroid B-type asteroids are a relatively uncommon type of carbonaceous asteroid, falling into the wider C-type asteroid#C-group asteroids, C-group; the 'B' indicates these objects are spectrally blue. In the asteroid population, B-class objects can be f ...

Rotation period

In February and March 1995, a rotational

lightcurve In astronomy, a light curve is a graph (discrete mathematics), graph of the Radiance, light intensity of a celestial object or region as a function of time, typically with the magnitude (astronomy), magnitude of light received on the ''y''-axis ...

of ''Celestia'' was obtained from photometric observations at the Paul Feder Observatory by Walter Worman of

Moorhead State University Minnesota State University Moorhead (MSUM) is a public university in Moorhead, Minnesota, across the Red River of the North from Fargo, North Dakota. The school has an enrollment of 7,534 students in 2019 and 266 full-time faculty members. MSUM ...

. Lightcurve analysis gave a

of 10.636 hours with a brightness amplitude of 0.26

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 ...

(). An alternative period determination by René Roy of 12 hours was based on a fragmentary lightcurve and received a poor rating ().

Diameter and albedo

According to the surveys carried out by the Infrared Astronomical Satellite

IRAS The Infrared Astronomical Satellite (Dutch language, Dutch: ''Infrarood Astronomische Satelliet'') (IRAS) was the first space telescope to perform a astronomical survey, survey of the entire night sky at infrared wavelengths. Launched on 25 Janu ...

, the Japanese Akari satellite and the

NEOWISE Wide-field Infrared Survey Explorer (WISE, observatory code C51, Explorer 92 and MIDEX-6) was a NASA infrared astronomy space telescope in the Explorers Program launched in December 2009.. . WISE discovered thousands of minor planets and nu ...

mission of NASA's

Wide-field Infrared Survey Explorer Wide-field Infrared Survey Explorer (WISE, List of observatory codes, observatory code C51, Explorer 92 and MIDEX-6) was a NASA infrared astronomy Space observatory, space telescope in the Explorers Program launched in December 2009.. . WISE L ...

, ''Celestia'' measures between 17.39 and 21.56 kilometers in diameter and its surface has an

albedo Albedo ( ; ) is the fraction of sunlight that is Diffuse reflection, diffusely reflected by a body. It is measured on a scale from 0 (corresponding to a black body that absorbs all incident radiation) to 1 (corresponding to a body that reflects ...

between 0.167 and 0.2573. The ''Collaborative Asteroid Lightcurve Link'' adopts the results obtained by IRAS, that is, an albedo of 0.2573 and a diameter of 17.39 kilometers based on an absolute magnitude of 10.89.

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:Celestia 001252 Named minor planets 001252 001252 19330219 Discoveries by Fred Lawrence Whipple