Leo Minor is a small and faint

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...

in the northern celestial hemisphere. Its name is Latin for "the smaller lion", in contrast to Leo, the larger lion. It lies between the larger and more recognizable

Ursa Major Ursa Major (; also known as the Great Bear) is a constellation in the northern sky, whose associated mythology likely dates back into prehistory. Its Latin name means "greater (or larger) bear," referring to and contrasting it with nearby Ursa ...

to the north and Leo to the south. Leo Minor was not regarded as a separate constellation by classical

astronomer An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, natural satellite, moons, comets and galaxy, g ...

s; it was designated by

Johannes Hevelius Johannes Hevelius Some sources refer to Hevelius as Polish: * * * * * * * Some sources refer to Hevelius as German: * * * * *of the Royal Society * (in German also known as ''Hevel''; pl, Jan Heweliusz; – 28 January 1687) was a councillor ...

in 1687. There are 37 stars brighter than

apparent magnitude Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's li ...

6.5 in the constellation; three are brighter than magnitude 4.5. 46 Leonis Minoris, an orange

giant In folklore, giants (from Ancient Greek: '' gigas'', cognate giga-) are beings of human-like appearance, but are at times prodigious in size and strength or bear an otherwise notable appearance. The word ''giant'' is first attested in 1297 fr ...

of magnitude 3.8, is located some 95

light-year A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...

s from Earth. At magnitude 4.4, Beta Leonis Minoris is the second-brightest star and the only one in the constellation with a

Bayer designation A Bayer designation is a stellar designation in which a specific star is identified by a Greek or Latin letter followed by the genitive form of its parent constellation's Latin name. The original list of Bayer designations contained 1,564 stars. ...

. It is a

binary star A binary star is a system of two stars that are gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved using a telescope as separate stars, in wh ...

, the brighter component of which is an orange giant and the fainter a yellow-white

main sequence In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Her ...

star. The third-brightest star is

21 Leonis Minoris 21 Leonis Minoris is a star in the constellation of Leo Minor. With an apparent magnitude of about 4.5, the star is faintly visible to the naked eye (see Bortle scale). Parallax estimates made by the '' Hipparcos'' spacecraft put it at ...

, a rapidly rotating white main-sequence star of average magnitude 4.5. The constellation also includes two stars with

planetary system A planetary system is a set of gravitationally In physics, gravity () is a fundamental interaction which causes mutual attraction between all things with mass or energy. Gravity is, by far, the weakest of the four fundamental interacti ...

s, two pairs of

interacting galaxies Interacting galaxies (''colliding galaxies'') are galaxies whose gravitational fields result in a disturbance of one another. An example of a minor interaction is a satellite galaxy disturbing the primary galaxy's spiral arms. An example of a ...

, and the unique

deep-sky object A deep-sky object (DSO) is any astronomical object that is not an individual star or Solar System object (such as Sun, Moon, planet, comet, etc.). The classification is used for the most part by amateur astronomers to denote visually observed f ...

Hanny's Voorwerp , (Dutch for ''Hanny's object'') is a rare type of astronomical object called a quasar ionization echo. It was discovered in 2007 by Dutch schoolteacher Hanny van Arkel while she was participating as a volunteer in the Galaxy Zoo project, part ...

History

The classical astronomers

Aratus Aratus (; grc-gre, Ἄρατος ὁ Σολεύς; c. 315 BC/310 BC240) was a Greek didactic poet. His major extant work is his hexameter poem ''Phenomena'' ( grc-gre, Φαινόμενα, ''Phainómena'', "Appearances"; la, Phaenomena), the fi ...

and

Ptolemy Claudius Ptolemy (; grc-gre, Πτολεμαῖος, ; la, Claudius Ptolemaeus; AD) was a mathematician, astronomer, astrologer, geographer, and music theorist, who wrote about a dozen scientific treatises, three of which were of importanc ...

had noted the region of what is now Leo Minor to be undefined and not containing any distinctive patterns; Ptolemy classified the stars in this area as ''amorphōtoi'' (not belonging to a constellation outline) within the constellation Leo.

first depicted Leo Minor in 1687 when he outlined ten new constellations in his star atlas ''Firmamentum Sobiescianum'', and included 18 of its objects in the accompanying ''Catalogus Stellarum Fixarum''. Hevelius decided upon Leo Minor or Leo Junior as a depiction that would align with its beastly neighbours the Lion and the Great Bear. In 1845, English astronomer

Francis Baily Francis Baily (28 April 177430 August 1844) was an English astronomer. He is most famous for his observations of "Baily's beads" during a total eclipse of the Sun. Baily was also a major figure in the early history of the Royal Astronomical S ...

revised the catalogue of Hevelius's new constellations, and assigned a Greek letter known as

to stars brighter than

4.5. Richard A. Proctor gave the constellation the name ''Leaena'' "the Lioness" in 1870, explaining that he sought to shorten the constellation names to make them more manageable on celestial charts. German astronomer

Christian Ludwig Ideler Christian Ludwig Ideler (21 September 1766 – 10 August 1846) was a German chronologist and astronomer. Life He was born in Gross-Brese near Perleberg. His earliest work was the editing in 1794 of an astronomical almanac for the Prussian gover ...

posited that the stars of Leo Minor had been termed ''Al Thibā' wa-Aulāduhā'' "Gazelle with her Young" on a 13th-century Arabic celestial globe, recovered by Cardinal

Stefano Borgia Stefano Borgia (3 December 1731 – 1804) was an Italian Cardinal, theologian, antiquarian, and historian. Life Cardinal Borgia belonged to a well known family of Velletri, where he was born, and was a member of the collateral branch of House ...

and housed in the prelate's museum at

Velletri Velletri (; la, Velitrae; xvo, Velester) is an Italian ''comune'' in the Metropolitan City of Rome, approximately 40 km to the southeast of the city centre, located in the Alban Hills, in the region of Lazio, central Italy. Neighbouring com ...

. Arabist Friedrich Wilhelm Lach describes a different view, noting that they had been seen as ''Al Haud'' "the Pond", which the Gazelle jumps into. In

Chinese astronomy Astronomy in China has a long history stretching from the Shang dynasty, being refined over a period of more than 3,000 years. The ancient Chinese people have identified stars from 1300 BCE, as Chinese star names later categorized in the twe ...

, the stars Beta, 30, 37 and 46 Leonis Minoris made up ''Neiping'', a "Court of Judge or Mediator", or ''Shi'' "Court Eunuch" or were combined with stars of the neighbouring Leo to make up a large celestial dragon or State Chariot. A line of four stars was known as ''Shaowei''; it represented four Imperial advisors and may have been located in Leo Minor, Leo or adjacent regions.

Characteristics

A dark area of the sky with a triangle of brighter stars just visible to the naked eye in good conditions, Leo Minor has been described by

Patrick Moore Sir Patrick Alfred Caldwell-Moore (; 4 March 1923 – 9 December 2012) was an English amateur astronomer who attained prominence in that field as a writer, researcher, radio commentator and television presenter. Moore was president of the Brit ...

as having "dubious claims to a separate identity". It is a small constellation bordered by

to the north,

Lynx A lynx is a type of wild cat. Lynx may also refer to: Astronomy * Lynx (constellation) * Lynx (Chinese astronomy) * Lynx X-ray Observatory, a NASA-funded mission concept for a next-generation X-ray space observatory Places Canada * Lynx, Ontar ...

to the west, Leo to the south, and touching the corner of

Cancer Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...

to the southwest. The three-letter abbreviation for the constellation, as adopted by the

International Astronomical Union The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreac ...

in 1922, is "LMi". The official constellation boundaries, as set by Belgian astronomer

Eugène Delporte Eugene is a common male given name that comes from the Greek εὐγενής (''eugenēs''), "noble", literally "well-born", from εὖ (''eu''), "well" and γένος (''genos''), "race, stock, kin".sides. In the

equatorial coordinate system The equatorial coordinate system is a celestial coordinate system widely used to specify the positions of celestial objects. It may be implemented in spherical or rectangular coordinates, both defined by an origin at the centre of Earth, a fund ...

, the

right ascension Right ascension (abbreviated RA; symbol ) is the angular distance of a particular point measured eastward along the celestial equator from the Sun at the March equinox to the (hour circle of the) point in question above the earth. When paired w ...

coordinates of these borders lie between and , while the

declination In astronomy, declination (abbreviated dec; symbol ''δ'') is one of the two angles that locate a point on the celestial sphere in the equatorial coordinate system, the other being hour angle. Declination's angle is measured north or south of the ...

coordinates are between 22.84° and 41.43°. Ranked 64th out of 88 constellations in size, Leo Minor covers an area of 232.0 square degrees, or 0.562 percent of the sky. It culminates each year at midnight on 24 February, and at 9 p.m. on 24 May.

Notable features

Stars

There are only three

star A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...

s in the constellation brighter than magnitude 4.5, and 37 stars with a magnitude brighter than 6.5. Leo Minor does not have a star designated Alpha because Baily erred and allocated a Greek letter to only one star, Beta. It is unclear whether he intended to give 46 Leonis Minoris a Bayer designation, as he recognized Beta and 46 Leonis Minoris as of the appropriate brightness in his catalogue. He died before revising his proofs, which might explain this star's omission. At magnitude 3.8, the brightest star in Leo Minor is an orange

spectral class 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 ...

K0III named 46 Leonis Minoris or Praecipua; its colour is evident when seen through binoculars. Situated from Earth, it has around 32 times the

luminosity Luminosity is an absolute measure of radiated electromagnetic power (light), the radiant power emitted by a light-emitting object over time. In astronomy, luminosity is the total amount of electromagnetic energy emitted per unit of time by a st ...

and is 8.5 times the size of the Sun. It was also catalogued and named as o Leonis Minoris by

Johann Elert Bode Johann Elert Bode (; 19 January 1747 – 23 November 1826) was a German astronomer known for his reformulation and popularisation of the Titius–Bode law. Bode determined the orbit of Uranus and suggested the planet's name. Life and career Bo ...

, which has been misinterpreted as Omicron Leonis Minoris. More confusion occurred with its proper name ''Praecipua'', which appears to have been originally applied to 37 Leonis Minoris in the 1814 ''Palermo Catalogue'' of

Giuseppe Piazzi Giuseppe Piazzi ( , ; 16 July 1746 – 22 July 1826) was an Italian Catholic priest of the Theatine order, mathematician, and astronomer. He established an observatory at Palermo, now the '' Osservatorio Astronomico di Palermo – Giuseppe ...

, who mistakenly assessed the latter star as the brighter. This name was later connected by Allen with 46 Leonis Minoris—an error perpetuated by subsequent astronomers. The original "Praecipua", 37 Leonis Minoris, has an apparent magnitude of 4.69, but is a distant yellow

supergiant Supergiants are among the most massive and most luminous stars. Supergiant stars occupy the top region of the Hertzsprung–Russell diagram with absolute visual magnitudes between about −3 and −8. The temperature range of supergiant stars spa ...

of spectral type G2.5IIa and absolute magnitude of −1.84, around distant. LeoMinorCC

Beta Leonis Minoris is a binary star system. The primary is a giant star of spectral class G9III and apparent magnitude of 4.4. It has around double the mass, 7.8 times the radius and 36 times the luminosity of the Earth's Sun. Separated by 0.1 to 0.6 second of arc from the primary, the secondary is a yellow-white main sequence star of spectral type F8. The two orbit around a common

centre of gravity In physics, the center of mass of a distribution of mass in space (sometimes referred to as the balance point) is the unique point where the weighted relative position of the distributed mass sums to zero. This is the point to which a force may ...

every 38.62 years, and lie away from the

Solar System The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar S ...

. Around away and around 10 times as luminous as the Sun,

is a rapidly rotating white main-sequence star, spinning on its axis in less than 12 hours and very likely flattened in shape. Of average apparent magnitude 4.5 and spectral type A7V, it is a

Delta Scuti variable A Delta Scuti variable (sometimes termed dwarf cepheid when the V-band amplitude is larger than 0.3 mag.) is a subclass of young pulsating star. These variables as well as classical cepheids are important standard candles and have been used to es ...

. These are short period (six hours at most) pulsating stars which have been used as standard candles and as subjects to study asteroseismology. Sidney Hall - Urania's Mirror - Leo Major and Leo Minor

Sidney Hall - Urania's Mirror - Leo Major and Leo Minor

Also known as SU and SV Leonis Minoris, 10 and 11 Leonis Minoris are yellow giants of spectral type G8III, with average magnitudes 4.54 and 5.34 respectively. Both are

RS Canum Venaticorum RS Canum Venaticorum is a binary star system in the northern constellation of Canes Venatici. It serves as the prototype to the class of RS Canum Venaticorum variables. The peak apparent visual magnitude of this system is below the lev ...

variables, with 10 Leonis Minoris varying by 0.012 magnitude over 40.4 days, and 11 Leonis Minoris by 0.033 magnitude over 18 days. 11 Leonis Minoris has a

red dwarf ''Red Dwarf'' is a British science fiction comedy franchise created by Rob Grant and Doug Naylor, which primarily consists of a television sitcom that aired on BBC Two between 1988 and 1999, and on Dave since 2009, gaining a cult following. T ...

companion of spectral type M5V and apparent magnitude 13.0. 20 Leonis Minoris is a multiple star system away from the Sun. The main star is another yellow star, this time a

dwarf Dwarf or dwarves may refer to: Common uses *Dwarf (folklore), a being from Germanic mythology and folklore * Dwarf, a person or animal with dwarfism Arts, entertainment, and media Fictional entities * Dwarf (''Dungeons & Dragons''), a humanoid ...

of spectral type G3Va and apparent magnitude 5.4. The companion is an old, active red dwarf that has a relatively high

metallicity In astronomy, metallicity is the abundance of elements present in an object that are heavier than hydrogen and helium. Most of the normal physical matter in the Universe is either hydrogen or helium, and astronomers use the word ''"metals"'' as a ...

and is of spectral type M6.5. The fact that the secondary star is brighter than expected indicates it is likely two stars very close together that are unable to be made out separately with current viewing technology. R and S Leonis Minoris are long-period

Mira variable Mira variables (named for the prototype star Mira) are a class of pulsating stars characterized by very red colours, pulsation periods longer than 100 days, and amplitudes greater than one magnitude in infrared and 2.5 magnitude at visual wavelen ...

s, while U Leonis Minoris is a

semiregular variable In astronomy, a semiregular variable star, a type of variable star, is a giant or supergiant of intermediate and late (cooler) spectral type showing considerable periodicity in its light changes, accompanied or sometimes interrupted by various irre ...

; all three are

red giant A red giant is a luminous giant star of low or intermediate mass (roughly 0.3–8 solar masses ()) in a late phase of stellar evolution. The outer atmosphere is inflated and tenuous, making the radius large and the surface temperature around or ...

s of spectral types M6.5e-M9.0e, M5e and M6 respectively. R varies between magnitudes 6.3 and 13.2 during a period of 372 days, S varies between magnitudes 8.6 and 13.9 during a period of 234 days, and U varies between magnitudes 10.0 and 13.3 during a period of 272 days. The lack of bright stars makes finding these objects challenging for amateur astronomers. G 117-B15A, also known as RY Leonis Minoris, is a

pulsating white dwarf A pulsating white dwarf is a white dwarf star whose luminosity varies due to non-radial gravity wave pulsations within itself. Known types of pulsating white dwarfs include DAV, or ZZ Ceti, stars, with hydrogen-dominated atmospheres and the s ...

of apparent magnitude 15.5. With a period of approximately 215 seconds, and losing a second every 8.9 million years, the 400-million-year-old star has been proposed as the most stable celestial clock. SX Leonis Minoris is a

dwarf nova A U Geminorum-type variable star, or dwarf nova (pl. novae) is one of several types of cataclysmic variable star, consisting of a close binary star system in which one of the components is a white dwarf that accretes matter from its companion. Dwa ...

of the SU Ursae Majoris type that was identified in 1994. It consists of a white dwarf and a donor star, which orbit each other every 97 minutes. The white dwarf sucks matter from the other star onto an

accretion disc An accretion disk is a structure (often a circumstellar disk) formed by diffuse material in orbital motion around a massive central body. The central body is typically a star. Friction, uneven irradiance, magnetohydrodynamic effects, and other ...

and heats up to between 6000 and 10000 K. The dwarf star erupts every 34 to 64 days, reaching magnitude 13.4 in these outbursts and remaining at magnitude 16.8 when quiet. Leo Minor contains another dwarf nova, RZ Leonis Minoris, which brightens to magnitude 14.2 from a baseline magnitude of around 17 but does so at shorter intervals than other dwarf novae. Two stars with planetary systems have been found. HD 87883 is an orange dwarf of magnitude 7.57 and spectral type K0V 18 parsecs distant from Earth. With a diameter three quarters that of Earth's sun, it is only 31 percent as luminous. It is orbited by a planet around 1.78 times the mass of Jupiter every 7.9 years, and there are possibly other smaller planets.

HD 82886 HD 82886 is an evolved subgiant star in the constellation Leo Minor. With an apparent magnitude 7.63, it is too faint to be seen with the unaided eye. Planetary system A planet 1.3 times the mass of Jupiter and orbiting at an approxi ...

(Illyrian) is a yellow dwarf of spectral type G0 and visual magnitude 7.63. A planet 1.3 times the mass of Jupiter and orbiting every 705 days was discovered in 2011.

Deep-sky objects

In terms of

s, Leo Minor contains many galaxies viewable in amateur telescopes. Located 3 degrees southeast of 38 Leonis Minoris, NGC 3432 is seen nearly edge on. It is of apparent magnitude 11.7 and measures 6.8 by 1.4 arcminutes. Located 42 million light-years away, it is moving away from the Solar System at a rate of 616 km per second. In 2000, a star within the galaxy brightened to magnitude 17.4, and has since been determined to be a luminous blue variable and

supernova impostor Supernova impostors are stellar explosions that appear at first to be a supernova but do not destroy their progenitor stars. As such, they are a class of extra-powerful novae. They are also known as Type V supernovae, Eta Carinae analogs, and gia ...

. It has tidal filaments and intense

star formation Star formation is the process by which dense regions within molecular clouds in The "medium" is present further soon.-->interstellar space

, so it was listed in

Halton Arp Halton Christian "Chip" Arp (March 21, 1927 – December 28, 2013) was an American astronomer. He was known for his 1966 ''Atlas of Peculiar Galaxies'', which (it was later theorized) catalogues many examples of interacting and merging galaxie ...

Atlas of Peculiar Galaxies The ''Atlas of Peculiar Galaxies'' is a catalog of peculiar galaxies produced by Halton Arp in 1966. A total of 338 galaxies are presented in the atlas, which was originally published in 1966 by the California Institute of Technology. The ...

. (webpage includes PDF link) NGC 3003, a SBbc

barred spiral galaxy A barred spiral galaxy is a spiral galaxy with a central bar-shaped structure composed of stars. Bars are found in about two thirds of all spiral galaxies, and generally affect both the motions of stars and interstellar gas within spiral galaxi ...

with an apparent magnitude of 12.3 and an angular size of 5.8 arcminutes, is seen almost edge-on.

NGC 3344 NGC 3344 is a relatively isolated barred spiral galaxy located 22.5 million light years away in the constellation Leo Minor (constellation), Leo Minor. This galaxy belongs to the group known as the Leo spur, which is a branch of the Virgo Supercl ...

, 25 million light-years distant, is face-on towards Earth. Measuring 7.1 by 6.5 arcminutes in size, it has an apparent magnitude of 10.45. NGC 3504 is a starburst barred spiral galaxy of apparent magnitude 11.67 and measuring 2.1 by 2.7 arcminutes. It has hosted supernovae in 1998 and 2001. It and the

spiral galaxy Spiral galaxies form a class of galaxy originally described by Edwin Hubble in his 1936 work ''The Realm of the Nebulae''NGC 3486 are also almost face-on towards Earth; the latter is of magnitude 11.05 and measures 7.1 by 5.2 arcminutes. NGC 2859 is an SB0-type

lenticular galaxy A lenticular galaxy (denoted S0) is a type of galaxy intermediate between an elliptical (denoted E) and a spiral galaxy in galaxy morphological classification schemes. It contains a large-scale disc but does not have large-scale spiral arms. ...

. At least two pairs of interacting galaxies have been observed. Arp 107 is a pair of galaxies in the process of merging, located 450 million light-years away. NGC 3395 and NGC 3396 are a spiral and irregular barred spiral galaxy, respectively, that are interacting, located 1.33 degrees southwest of 46 Leonis Minoris. The unique deep-sky object known as

was discovered in Leo Minor in 2007 by Dutch school teacher Hanny van Arkel while participating as a volunteer in the

Galaxy Zoo Galaxy Zoo is a crowdsourced astronomy project which invites people to assist in the morphological classification of large numbers of galaxies. It is an example of citizen science as it enlists the help of members of the public to help in scien ...

project. Lying near the 650-million-light-year-distant spiral galaxy IC 2497, it is around the same size as the

Milky Way The Milky Way is the galaxy that includes our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye ...

. It contains a 16,000-light-year-wide hole. The voorwerp is thought to be the visual light echo of a

quasar A quasar is an extremely Luminosity, luminous active galactic nucleus (AGN). It is pronounced , and sometimes known as a quasi-stellar object, abbreviated QSO. This emission from a galaxy nucleus is powered by a supermassive black hole with a m ...

now gone inactive, possibly as recently as 200,000 years ago.

Meteor shower

Discovered by Dick McCloskey and Annette Posen of the Harvard Meteor Program in 1959, the Leonis Minorid meteor shower peaks between 18 and 29 October. The shower's parent body is the long period comet C/1739 K1 (Zanotti). It is a minor shower, and can only be seen from the Northern Hemisphere.

References

Citations Sources * * * * * * * * * * * * * * * * * * * * * * Online sources * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

External links

The Deep Photographic Guide to the Constellations: Leo Minor
{{DEFAULTSORT:Leo Minor Northern constellations Constellations listed by Johannes Hevelius Constellations