4388 Jürgenstock, provisional designation , is a bright Phocaea asteroid from the inner regions of the

asteroid belt The asteroid belt is a torus-shaped region in the Solar System, located roughly between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies, of many sizes, but much smaller than planets, called ...

, approximately in diameter. It was discovered on 3 November 1964, by astronomers at

Indiana University Indiana University (IU) is a system of public universities in the U.S. state of Indiana. Campuses Indiana University has two core campuses, five regional campuses, and two regional centers under the administration of IUPUI. *Indiana Universit ...

during the

Indiana Asteroid Program The Indiana Asteroid Program was a photographic astronomical survey of asteroids during 1949–1967, at the U.S. Goethe Link Observatory near Brooklyn, Indiana. The program was initiated by Frank K. Edmondson of Indiana University using a 10-inc ...

Goethe Link Observatory The Goethe Link Observatory, observatory code 760, is an astronomical observatory near Brooklyn, Indiana, United States. It is owned by Indiana University and operated by the Indiana Astronomical Society https://iasindy.org/about.html, which eff ...

in Indiana, United States. The assumed

S-type asteroid S-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 of this type, making it the second ...

has a short

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 2.8 hours and is rather spherical in shape. It was named for German-Venezuelan astronomer

Jürgen Stock Jürgen Stock (born October 4, 1959) is a German police officer and academic. He has served as secretary general of Interpol since November 7, 2014. Biography Stock was born on October 4, 1959, in Wetzlar, Germany. He joined the Kriminalpolizei ...

. In February 2019, the asteroid occulted the brightest star in the night sky,

Sirius Sirius is the list of brightest stars, brightest star in the night sky. Its name is derived from the Ancient Greek language, Greek word , or , meaning 'glowing' or 'scorching'. The star is designated α Canis Majoris, Latinisation ...

Orbit and classification

This asteroid 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 ...

asteroid belt at a distance of 1.7–3.0 AU once every 3 years and 7 months (1,307 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 2.34 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 0.28 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 Plane of reference, reference plane and the orbital plane or Axis of rotation, axis of direction of the orbiting object ...

of 25 ° with respect to the

ecliptic The ecliptic or ecliptic plane is the orbital plane of the Earth around the Sun. From the perspective of an observer on Earth, the Sun's movement around the celestial sphere over the course of a year traces out a path along the ecliptic again ...

. 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 its first observation at the

Purple Mountain Observatory The Purple Mountain Observatory (), also known as Zijinshan Astronomical Observatory is an astronomical observatory located on the Purple Mountain in the east of Nanjing. Description The Purple Mountain Observatory was established in 1934 fun ...

in Nanking, China, just four nights prior to its official discovery observation at Goethe Link. ''Jürgenstock'' is a member of the Phocaea family (), a large collisional

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

of nearly 2000 stony asteroids, which is named after 25 Phocaea. As with the Hungarias, many Phocaeans are also

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 in ...

s due to their eccentric orbits. However, ''Jürgenstock'' just stays shy of the orbit of

Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury (planet), Mercury. In the English language, Mars is named for the Mars (mythology), Roman god of war. Mars is a terr ...

(1.66 AU) with a relatively small

Minimum orbit intersection distance Minimum orbit intersection distance (MOID) is a measure used in astronomy to assess potential close approaches and collision risks between astronomical objects. It is defined as the distance between the closest points of the osculating orbits of ...

(MOID) of . Moreover, in an alternative HCM-analysis by

Milani Milani (or Milāni) is an Italian surname. Notable people with the surname include: *Abbas Milani (born 1949), Iranian-American historian and author *Alfredo Milani (born 1924), Italian motorcycle racer *Andrea Milani, several people ** Andrea Mila ...

and Knežević, it has been considered a

background asteroid 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 ...

rather than a member of the Phocaea family. On 3 July 2041, ''Jürgenstock'' will approach the 200-kilometer sized asteroid 7 Iris at a distance of with a relative velocity of 5.66 km/s.

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 German-Venezuelan astronomer

(born 1923), prominent developer of observatories and director of both the South American Cerro Tololo and the

Llano del Hato National Astronomical Observatory The Llano del Hato National Astronomical Observatory ( es, OAN de Llano del Hato, or Observatorio Astronómico Nacional de Llano del Hato, code: 303) is an astronomical observatory in Venezuela. It is 3600 meters above sea level and is the coun ...

in Chile and Venezuela, respectively. 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 ...

on 28 September 1999 ().

Occultation of Sirius

On 19 February 2019, between 5:11 and 5:32 UTC, ''Jürgenstock'' occulted the star

in the constellation

Canis Major Canis Major is a constellation in the Southern Celestial Hemisphere, southern celestial hemisphere. In the second century, it was included in Ptolemy's 48 constellations, and is counted among the 88 modern constellations. Its name is Latin fo ...

, the brightest star in the night sky. The shadow crossed Southern Argentina, Southern Chile, Central America, and the Caribbean. Occultations are typically an excellent method to determine a minor planet's dimension (cross-section) by exactly measuring the duration of the event.

Physical characteristics

''Jürgenstock'' is an assumed

, in agreement with the Phocea family's overall

spectral type In astronomy, stellar classification is the classification of stars based on their stellar spectrum, spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a Prism (optics), prism or diffraction grati ...

Rotation period

In September 2007, a rotational

lightcurve In astronomy, a light curve is a graph of light intensity of a celestial object or region as a function of time, typically with the magnitude of light received on the y axis and with time on the x axis. The light is usually in a particular frequ ...

of ''Jürgenstock'' was obtained from photometric observations by Federico Manzini at the Sozzago Astronomical Station in Italy. Lightcurve analysis gave a

of hours with a brightness variation of 0.11

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 ...

, indicative of a spherical rather than elongated shape (). In July 2014, a similar period determination of hours and an amplitude of 0.10 magnitude was made by Brian Warner at the Palmer Divide Station in California (). While Manzini and/or

Raoul Behrend This is a list of minor-planet discoverers credited by the Minor Planet Center with the discovery of one or several minor planets (such as near-Earth and main-belt asteroids, Jupiter trojans and distant objects). , the discovery of 612,011 num ...

suspected it to be an asynchronous

binary asteroid A binary asteroid is a system of two asteroids orbiting their common barycenter. The binary nature of 243 Ida was discovered when the Galileo spacecraft flew by the asteroid in 1993. Since then numerous binary asteroids and several triple a ...

with a

minor-planet moon A minor-planet moon is an astronomical object that orbits a minor planet as its natural satellite. , there are 457 minor planets known or suspected to have moons. Discoveries of minor-planet moons (and binary objects, in general) are importan ...

in its orbit, Warner did not mention any anomalies in the lightcurve, and the ''Lightcurve Data Base'' does not flag the body as a potential binary system.

Diameter and albedo

According to the survey carried out by the

NEOWISE Wide-field Infrared Survey Explorer (WISE, observatory code C51, Explorer 92 and SMEX-6) is a NASA infrared astronomy space telescope in the Explorers Program. It was launched in December 2009, and placed in hibernation mode in February 2011, ...

mission of NASA's

Wide-field Infrared Survey Explorer Wide-field Infrared Survey Explorer (WISE, observatory code C51, Explorer 92 and SMEX-6) is a NASA infrared astronomy space telescope in the Explorers Program. It was launched in December 2009, and placed in hibernation mode in February 2011, ...

, ''Jürgenstock'' measures 4.69 kilometers in diameter and its surface has a relatively high

albedo Albedo (; ) is the measure of the diffuse reflection of sunlight, solar radiation out of the total solar radiation and measured on a scale from 0, corresponding to a black body that absorbs all incident radiation, to 1, corresponding to a body ...

of 0.32. The ''Collaborative Asteroid Lightcurve Link'' assumes a standard albedo for a Phocaean asteroid of 0.23 and calculates a diameter of 5.79 kilometers based on an

absolute magnitude Absolute magnitude () is a measure of the luminosity of a celestial object on an inverse Logarithmic scale, logarithmic Magnitude (astronomy), astronomical magnitude scale. An object's absolute magnitude is defined to be equal to the apparent mag ...

of 13.4.

Notes

References

External links

Occultation update for (4388) Jurgenstock
IOTA/IOTA-ES
Asteroid Lightcurve Database (LCDB)
query form

)
Dictionary of Minor Planet Names
Google books

– Observatoire de Genève, Raoul Behrend

– Minor Planet Center * * {{DEFAULTSORT:Jurgenstock 004388 004388 Named minor planets 19641103