1726 Hoffmeister, provisional designation , is a carbonaceous

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 ...

and namesake of the Hoffmeister family from the central region 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 23 kilometers in diameter. It was discovered on 24 July 1933, by German astronomer

Karl Reinmuth Karl Wilhelm Reinmuth (4 April 1892 in Heidelberg – 6 May 1979 in Heidelberg) was a German astronomer and a prolific discoverer of 395 minor planets. Scientific career From 1912 to 1957, Reinmuth was working as an astronomer at the He ...

Heidelberg Observatory Heidelberg (; ; ) is the List of cities in Baden-Württemberg by population, fifth-largest city in the States of Germany, German state of Baden-Württemberg, and with a population of about 163,000, of which roughly a quarter consists of studen ...

in southwest Germany, and named after astronomer

Cuno Hoffmeister Cuno Hoffmeister (2 February 1892 – 2 January 1968) was a German astronomer, observer and discoverer of variable stars, comets and minor planets, and founder of Sonneberg Observatory. Born in Sonneberg in 1892 to Carl and Marie Hoffmeister, Cu ...

Orbit and classification

''Hoffmeister'' is the namesake and lowest-numbered member of the very compact Hoffmeister family (), which, based upon its low albedo, was most likely formed from the breakup of a 50–100 kilometer-sized, carbon-rich

parent body A parent body in meteoritics is the celestial body from which originates a meteorite or a class of meteorites. Identification It is easiest to correlate a meteorite with a parent body when the parent body still exists. This is the case for Lun ...

within the past several hundred million years. It orbits the Sun in the central main-belt at a distance of 2.7–2.9 AU once every 4 years and 8 months (1,700 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 2.79 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 0.04 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 3 ° 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 ...

. It was first identified as 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 1924, extending the asteroid'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 ...

by 9 years prior to its official discovery observation at Heidelberg.

Physical characteristics

In the

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 ...

, ''Hoffmeister'' is characterized as a Cb-type, a subtype of the carbonaceous C-complex.

Diameter and albedo

According to the surveys carried out by the Japanese

Akari AKARI (ASTRO-F) was an infrared astronomy satellite developed by Japan Aerospace Exploration Agency, in cooperation with institutes of Europe and Korea. It was launched on 21 February 2006, at 21:28 UTC (06:28, 22 February JST) by M-V rocket ...

satellite and 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 ...

with its subsequent

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, ''Hoffmeister'' measures between 22.03 and 25.67 kilometers in diameter, and its surface has a low

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 0.03 and 0.05. The ''Collaborative Asteroid Lightcurve Link'' assumes a standard albedo for carbonaceous asteroids of 0.057 and calculates a diameter of 17.4 kilometers with an absolute magnitude of 12.53.

Rotational lightcurve

In December 2009, 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 ''Hoffmeister'' was obtained from photometric observations by astronomers at the

Palomar Transient Factory The Palomar Transient Factory (PTF, obs. code: I41), was an astronomical survey using a wide-field survey camera designed to search for optical transient and variable sources such as variable stars, supernovae, asteroids and comets. The projec ...

in California. It gave 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 hours with a brightness variation of 0.40

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 ...

().

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 in memory of German astronomer

(1892–1968), who founded the

Sonneberg Observatory Sonneberg Observatory () is an astronomical observatory located at 638 m altitude on Erbisbühl in the Neufang district of Sonneberg, Germany. The observatory was founded in 1925 on the initiative of Cuno Hoffmeister by the town of Sonneber ...

in 1925, and became one of its directors ''(see 1039 Sonneberga)''. Hoffmeister discovered thousands of

variable star A variable star is a star whose brightness as seen from Earth (its apparent magnitude) changes systematically with time. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are ...

s, co-discovered comet C/1959 O1, thoroughly investigated a large number of

meteor A meteor, known colloquially as a shooting star, is a glowing streak of a small body (usually meteoroid) going through Earth's atmosphere, after being heated to incandescence by collisions with air molecules in the upper atmosphere, creating a ...

s, and discovered 5 minor planets:

2183 Neufang Year 183 ( CLXXXIII) was a common year starting on Tuesday of the Julian calendar. At the time, it was known in Rome as the Year of the Consulship of Aurelius and Victorinus (or, less frequently, year 936 ''Ab urbe condita''). The denomination ...

, 3203 Huth,

3674 Erbisbühl 3674 Erbisbühl ( ''prov. designation'': ) is an stony asteroid and one of the largest Mars-crossers from the innermost regions of the asteroid belt, approximately in diameter. It was discovered on 13 September 1963, by German astronomer Cuno Ho ...

, 4183 Cuno (which was later named after him) and

4724 Brocken 47, 47 or forty-seven may refer to: *47 (number) *47 BC * AD 47 *1947 *2047 *'47 (brand), an American clothing brand * ''47'' (magazine), an American publication * 47 (song), a song by Sidhu Moose Wala *47, a song by New Found Glory from the albu ...

. The lunar crater ''

Hoffmeister Hoffmeister is a German surname. Notable people with the surname include: *Adolf Hoffmeister (1902–1973), Czechoslovak artist *Bert Hoffmeister (1907–1999), Canadian Army officer, businessman, and conservationist *Cuno Hoffmeister (1892–1968) ...

'' was also named in his honor. 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. Funct ...

on 20 February 1976 ().

Orbit and classification

Physical characteristics

Diameter and albedo

Rotational lightcurve

Naming

References

External links