11277 Ballard (

provisional designation Provisional designation in astronomy is the naming convention applied to astronomical objects immediately following their discovery. The provisional designation is usually superseded by a permanent designation once a reliable orbit has been calcu ...

) is a Phocaea asteroid from the inner regions of the

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 ...

, approximately in diameter. It was discovered on 8 October 1988, by American astronomer couple

Carolyn Carolyn is a female given name, a variant of Caroline. Other spellings include Carolin, Karolyn, Carolyne, Carolynn or Carolynne. Caroline itself is one of the feminine forms of Charles. List of notable people * Carolyn Bennett (born 1950 ...

and

Eugene Shoemaker Eugene Merle Shoemaker (April 28, 1928 – July 18, 1997) was an American geologist. He co-discovered Comet Shoemaker–Levy 9 with his wife Carolyn S. Shoemaker and David H. Levy. This comet hit Jupiter in July 1994: the impact was telev ...

at the

Palomar Observatory The Palomar Observatory is an astronomical research observatory in the Palomar Mountains of San Diego County, California, United States. It is owned and operated by the California Institute of Technology (Caltech). Research time at the observat ...

in California. The assumed

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 at least 10 hours. It was named for American marine scientist

Robert Ballard Robert Duane Ballard (born June 30, 1942) is an American retired Navy officer and a professor of oceanography at the University of Rhode Island who is noted for his work in underwater archaeology (maritime archaeology and archaeology of ...

Orbit and classification

Ballard is a member of the

Phocaea family The Phocaea family ( ; adj. ''Phocaean''; ) is a collisional family of asteroids located between 2.25 and 2.5 AU in the inner region of the asteroid belt. Phocaea asteroids are of stony S-type composition and have orbits with eccentricities ...

(). It orbits the Sun in the inner asteroid belt at a distance of 1.83–2.98 AU once every 3 years and 9 months (1,360 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 2.4 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 0.24 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 23 ° 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 with a

precovery In astronomy, precovery (short for pre-discovery recovery) is the process of finding the image of a celestial object in images or photographic plates predating its discovery, typically for the purpose of calculating a more accurate orbit. This ha ...

taken at

Palomar Palomar may refer to: Places * Any of several locations in San Diego County, California: ** Palomar Mountain *** Palomar Mountain, California, an unincorporated community ** Palomar College in San Marcos, California *** Palomar College Transit Ce ...

in September 1988, just four weeks prior to its official discovery observation. Ballard is not a

Mars-crosser A Mars-crossing asteroid (MCA, also Mars-crosser, MC) is an asteroid whose orbit crosses that of Mars. Some Mars-crossers numbered below 100000 are listed here. They include the two numbered Mars trojans 5261 Eureka and . Many databases, for i ...

, since its

aphelion An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. The line of apsides (also called apse line, or major axis of the orbit) is the line connecting the two extreme values. Apsides perta ...

is larger than 1.67 AU.

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 American marine scientist

(born 1942), a professor of

oceanography Oceanography (), also known as oceanology, sea science, ocean science, and marine science, is the scientific study of the ocean, including its physics, chemistry, biology, and geology. It is an Earth science, which covers a wide range of to ...

and director of the ''Deep Submergence Laboratory'', who is known for the discovery of the RMS ''Titanic'' and the

German battleship Bismarck ''Bismarck'' was the first of two s built for Nazi Germany's . Named after Chancellor Otto von Bismarck, the ship was Keel laying, laid down at the Blohm & Voss shipyard in Hamburg in July 1936 and ceremonial ship launching, launched in Februar ...

. 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. Funct ...

on 26 May 2002 ().

Physical characteristics

Ballard is an assumed, stony

, in line with the Phocaea family's overall

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 ...

Rotation period

In July 2010, 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 Ballard was obtained from two nights of photometric observations in the R-band by Italian astronomer Albino Carbognani at the OAVdA Observatory in Italy. Lightcurve analysis gave a tentative

of at least 10 hours with a brightness amplitude of more than 0.25

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 ...

().

Diameter and albedo

According to the survey carried out by 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 ...

, Ballard measures between 5.65 and 6.445 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 0.19 and 0.289. The ''Collaborative Asteroid Lightcurve Link'' assumes an albedo of 0.23 – derived from the family's largest member,

25 Phocaea 25 Phocaea () is a stony asteroid from the inner regions of the asteroid belt, approximately 75 kilometers in diameter. It is the parent body of the Phocaea family. Discovered by Jean Chacornac in 1853, it was named after the ancient Greek city ...

– and calculates a diameter of 6.65 kilometers based on an absolute magnitude of 13.1.

References

External links

Asteroid Lightcurve Database (LCDB)
query form

)
Dictionary of Minor Planet Names
Google books

– Minor Planet Center * * {{DEFAULTSORT:Ballard 011277 Discoveries by Carolyn S. Shoemaker Discoveries by Eugene Merle Shoemaker Named minor planets 19881008