The classical astronomers Aratus and Ptolemy had noted the region of what is now Leo Minor to be undefined and not containing any distinctive pattern; Ptolemy classified the stars in this area as amorphōtoi (not belonging to a constellation outline) within the constellation Leo.
Johannes Hevelius 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 revised the catalogue of Hevelius’s new constellations, and assigned a Greek letter known as Bayer designation to stars brighter than apparent magnitude 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 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 and housed in the prelate’s museum at Velletri. Arabist Friedrich Wilhelm Lach describes a different view, noting that they had been seen as ‘Al Haud,’ ‘the Pon,’ which the Gazelle jumps into.
In Chinese astronomy, 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.
[http://www.go-astronomy.com/constellations.php?Name=Leo%20Minor]
[http://astropixels.com/constellations/charts/LMi.html]
There are only three stars 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.
[https://jumk.de/astronomie/big-stars/praecipua.shtml]
At magnitude 3.8, the brightest star in Leo Minor is an orange giant of spectral class K0III named 46 Leonis Minoris or Praecipua; its colour is evident when seen through binoculars. Situated 95 light-years (29 parsecs) from Earth, it has around 32 times the luminosity and is 8.5 times the size of the Sun.
Its proper name is derived from the Latin ‘the Chief (Star of Leo Minor).’ The name may originally have referred to 37 Leonis Minoris, and later mistransfered to this star.
[https://en.wikipedia.org/wiki/46_Leonis_Minoris]
Beta Leonis Minoris is a binary star system. The primary is a giant star of spectral class G8 and apparent magnitude of 4.4. It has around double the mass, 7.8 times the radius and is 36 times the luminosity of the Earth’s Sun. Separated by 11 seconds of arc from the primary, the secondary is a yellow-white main sequence star of spectral type F8. The two orbit around a common center of gravity every 38.62 years, and lie 154 light-years (47 parsecs) away from the Solar System.
Around 98 light-years (30 parsecs) away and around 10 times as luminous as the Sun, 21 Leonis Minoris 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. These are short period (six hours at most) pulsating stars which have been used as standard candles and as subjects to study asteroseismology.
20 Leonis Minoris is a multiple star system 49 light-years (15 parsecs) away from the Sun. The main star is another yellow star, this time a dwarf of spectral type G3Va and apparent magnitude 5.4. The companion is an old, active red dwarf that has a relatively high metallicity 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 Leonis Minoris (R LMi) is a Mira variable type star in the constellation Leo Minor. It ranges between apparent magnitude 6.3 and 13.2, and spectral types M6.5e to M9.0e (Tc:), over a period of 372 days.
[https://en.wikipedia.org/wiki/R_Leonis_Minoris]
G117-B15A is a small, well-observed variable white dwarf star of the DAV, or ZZ Ceti, type in the constellation of Leo Minor. The star was found to be variable in 1974, and In 1984 it was demonstrated that the star’s variability is due to non-radial gravity wave pulsations. As a consequence, its timescale for period change is directly proportional to its cooling timescale, allowing its cooling rate to be measured using astroseismological techniques.
The age of G117-B15A is estimated at 400 million years. Its light curve has a dominant period of 215.2 seconds, which is estimated to increase by approximately one second each 14 million years. This star has been claimed to be the most stable optical clock ever found, much more stable than the ticks of an atomic clock. It is also the first pulsating white dwarf to have its main pulsation mode index identified.
[https://en.wikipedia.org/wiki/G_117-B15A]
SX Leonis Minoris is a dwarf nova 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 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 in Leo Minor. 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 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.
In terms of deep-sky objects, Leo Minor contains many galaxies viewable in amateur telescopes:
NGC 3432, sometimes known as the Knitting Needle Galaxy, lies 3 degrees southeast of the star 38 Leonis Minoris. It appears almost edge-on and can be observed in amateur telescopes. The galaxy has an apparent visual magnitude of 11.67 and is about 42 million light years distant from the solar system:
[http://www.constellation-guide.com/constellation-list/leo-minor-constellation/]
[http://www.jwinman.com/starcharts/NGC%203432%20chart.htm]
NGC 3344 is a relatively isolated barred spiral galaxy which belongs to the group known as the Leo spur, which is a branch of the Virgo Supercluster. NGC 3344 has the morphological classification (R)SAB(r)bc, which indicates it is a weakly barred spiral galaxy that exhibits rings and moderate to loosely wound spiral arms. There is both an inner and outer ring, with the prominent arms radiating outward from the inner ring and the slightly elliptical bar being situated inside. At the center of the bar is an HII nucleus with an angular diameter of about 3″:
[https://en.wikipedia.org/wiki/NGC_3344]
Hubble sees galaxy in a spin
NGC 3344 is a glorious spiral galaxy around half the size of the Milky Way, which lies 25 million light-years distant. We are fortunate enough to see NGC 3344 face-on, allowing us to study its structure in detail.
The galaxy features an outer ring swirling around an inner ring with a subtle bar structure in the center. A bar is an elongated distribution of stars and gas in the center of a spiral galaxy. The central regions of the galaxy are predominately populated by young stars, with the galactic fringes also featuring areas of active star formation.
Central bars are found in around two thirds of spiral galaxies. NGC 3344’s is clearly visible here, although it is not as dramatic as in some galaxies.
The high density of stars in galaxies’ central regions gives them enough gravitational influence to affect the movement of other stars in their galaxy. However, NGC 3344’s outer stars are moving in an unusual manner, although the presence of the bar cannot entirely account for this, leaving astronomers puzzled. It is possible that in its past NGC 3344 passed close by another galaxy and acquired stars from it, but more research is needed to state this with confidence.
The image is a combination of exposures taken in visible and near-infrared light, using Hubble’s Advanced Camera for Surveys. The field of view is around 3.4 by 3.4 arcminutes, or around a tenth of the diameter of the full moon.
[https://www.nasa.gov/mission_pages/hubble/science/ngc3344.html]
NGC 3021 is a small spiral galaxy in the constellation Leo Minor which lies about 100 million light-years away from Earth:
NGC 3021: A cosmological measuring tape
This NASA/ESA Hubble Space Telescope image shows the spiral galaxy NGC 3021 which lies about 100 million light-years away in the constellation of Leo Minor (The Little Lion).
Among many other types of stars, this galaxy contains Cepheid variable stars, which can be used work out the distance to the galaxy. These stars pulsate at a rate that is closely related to their intrinsic brightness, so measurements of their rate of pulsation and their observed brightness give astronomers enough information to calculate the distance to the galaxy itself.
Cepheids are also used to calibrate an even brighter distance marker, that can be used over greater distances: Type Ia supernovae. One of these bright exploding stars was observed in NGC 3021, back in 1995.
In addition, the supernova in NGC 3021 was also used to refine the measurement of what is known as the Hubble constant. The value of this constant defines how fast the Universe is expanding and the more accurately we know it the more we can understand about the evolution of the Universe in the past as well as in the future. So, there is much more to this galaxy than just a pretty spiral.
[https://www.spacetelescope.org/images/potw1513a/]
Arp 107 is a set of galaxies about 450 million light-years away in the constellation Leo Minor. The galaxies are in the process of colliding and merging:
[https://en.wikipedia.org/wiki/Arp_107]
Interacting galaxy pair Arp 107
NASA’s Spitzer Space Telescope’s sensitive infrared detectors map out faint regions of new star formation in this pair of colliding galaxies known as Arp 107. Like a beautiful pearl necklace, young star clusters have formed along the ring-like tidal arm in this system. Spitzer images at 8 microns (middle picture) provide a clear view of these clumps of young stars. In contrast, in the shorter wavelength 3.6 micron band (left picture), the older stars in the small companion to the northeast and the bridge connecting the two galaxies are bright. The color-coded multi-band picture (right picture; red=8.0 microns, blue=3.6 microns) emphasizes this difference in stellar ages.
North is up and east is to the left on these images. The field of view is 3 arcminutes.
[http://www.spitzer.caltech.edu/images/2344-sig05-006a-Interacting-Galaxy-Pair-Arp-107]
The unique deep-sky object known as Hanny’s Voorwerp was discovered in Leo Minor in 2007 by Dutch school teacher Hanny van Arkel while participating as a volunteer in the Galaxy Zoo project. Lying near the 650-million-light-year-distant spiral galaxy IC 2497, it is around the same size as the Milky Way. It contains a 16,000-light-year-wide hole. The voorwerp is thought to be the visual light echo of a quasar now gone inactive, possibly as recently as 200,000 years ago:
Hanny’s Voorwerp
Hanny’s Voorwerp, Dutch for ‘Hanny’s Object,’ is enormous, about the size of our own Milky Way Galaxy. Glowing strongly in the greenish light produced by ionized oxygen atoms, the mysterious voorwerp is below spiral galaxy IC 2497 in this view from the Hubble Space Telescope. Both lie at a distance of some 650 million light-years in the faint constellation Leo Minor. In fact, the enormous green cloud is now suspected to be part of a tidal tail of material illuminated by a quasar inhabiting the center of IC 2497. Powered by a massive black hole, the quasar suddenly turned off, leaving only galaxy and glowing voorwerp visible in telescopes at optical wavelengths. The sharp Hubble image also resolves a star forming region in the voorwerp, seen in yellow on the side near IC 2497. That region was likely compressed by an outflow of gas driven from the galaxy's core. The remarkable mystery object was discovered by Dutch schoolteacher Hanny van Arkel in 2007 while participating online in the Galaxy Zoo project. Galaxy Zoo enlists the public to help classify galaxies found in the Sloan Digital Sky Survey, and more recently in deep Hubble imagery.
[https://apod.nasa.gov/apod/ap110210.html]
SDSS J1004+4112 is a cluster of galaxies that acts as a huge gravitational lens:
A five quasar gravitational lens
What’s happening near the center of this cluster of galaxies? At first glance, it appears that several strangely elongated galaxies and fully five bright quasars exist there. In reality, an entire cluster of galaxies is acting as a gigantic gravitational lens that distorts and multiply-images bright objects that occur far in the distance. The five bright white points near the cluster center are actually images of a single distant quasar. This Hubble Space Telescope image is so detailed that even the host galaxy surrounding the quasar is visible. Close inspection of the above image will reveal that the arced galaxies at 2 and 4 o'clock are actually gravitationally lensed images of the same galaxy. A third image of that galaxy can be found at about 10 o'clock from the cluster center. Serendipitously, numerous strange and distant galaxies dot the above image like colorful jewels. The cluster of galaxy that acts as the huge gravitational lens is cataloged as SDSS J1004+4112 and lies about 7 billion light years distant toward the constellation of Leo Minor.
[https://apod.nasa.gov/apod/ap060524.html]
Leo Minorids is a weak meteor shower that takes place from October 19 till October 27 each year. With a weak moon the meteor shower may be visible with the naked eye, however this meteor shower is best observed only from the Northern Hemisphere with telescopic plotting. This meteor shower is linked to comet C/1739 K1 and radiates from the constellation Leo Minor. The meteor shower often only produces 2 meteors an hour.
[https://en.wikipedia.org/wiki/Leonis_Minorids]
[https://en.wikipedia.org/wiki/Leo_Minor]
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