While the Greek astronomers Ptolemy and Aratus considered the region now occupied by Leo Minor to be empty, or at least, not organized into a recognizable pattern, the Polish astronomer Johannes Hevelius thought otherwise. Therefore, to bring order where chaos reigned, in 1687 he co-opted 18 of the stars between Ursa Major to the north, Cancer to the southwest, Lynx to the west, and Leo to the south into a pattern he called Leo Minor (“Smaller Lion”). The constellation ranks at 64th in terms of size, taking up an area of just 232 square degrees of the night sky between latitudes +90° and -40°
Leo Minor is a diminutive and faint northern sky constellation that requires exceptionally good eyesight and seeing conditions to be seen at all, and even then an observer is likely to only see its three brightest stars that form a triangle. In the northern hemisphere, Leo Minor can be seen during the winter and spring time, with the constellation reaching its highest point above the horizon at midnight (Local Time) on February 24th, and again three months later, at 9 PM (Local Time) on May 24th. On star charts, the constellation’s shape resembles a stingray with its “tail” extending toward the constellation Lynx. Look for Leo Minor between the constellations Leo to the south, Cancer to the southeast, Ursa Major to the north, and Lynx to the west.
Ursa Major Constellation Family
Leo Minor is a member of the Ursa Major family of constellations, together with Boötes, Camelopardalis, Canes Venatici, Coma Berenices, Corona Borealis, Draco, Lynx, Ursa Major and Ursa Minor.
Having been created by Polish astronomer Johannes Hevelius in 1687, there are no myths associated with Leo Minor. In fact, Hevelius, decided upon the constellation’s name only because he placed it near to two constellations with “beastly” associations, namely Ursa Major (“Great Bear”), and Leo (“Lion”). Although Leo Minor does not represent any Greek or Roman mythological characters in Western tradition, there is some evidence to suggest that it did represent four celestial judges or advisors in Chinese mythology, and a “Gazelle with her Young” in Arabian astronomy.
– Praecipua (46 Leonis Minoris), the constellation’s brightest star, is an orange sub giant (K0+III-IV) located about 95 light years away with a visual magnitude of 3.83. It is 8.5 times bigger than the Sun, 32 times as bright, and 1.5 times more massive. The name Praecipua derives from the Latin for “the chief [star of Leo Minor]”.
– Beta Leonis Minoris, the second most luminous star in the constellation, is a binary system found about 146 light years from our solar system with a visual magnitude of 4.22. The two stars are both yellow colored, with the primary component a yellow subgiant (G8III-IV) of magnitude 4.40, that is 7.8 times as big as our sun, twice as massive, and 36 times brighter. The second component is a yellow-white subgiant (F8IV) of magnitude 6.12, that has twice the Sun’s size, 1.35 times its mass, and 5.8 times its brightness.
– 21 Leonis Minoris, the constellation’s third brightest star, is white dwarf (A7V) situated 92 light years distant that shines with an apparent magnitude of 4.49. It has 1.6 times the Sun’s mass, and 10 times its luminosity.
– RY Leonis Minoris (G 117-B15A) is a pulsating white dwarf with an apparent visual magnitude of 15.5. There are many similar white dwarfs in the sky, but this particular 400-million-year-old example’s pulsation period of 215 seconds is so stable that it loses only about one second in every 8.9 million years, making it the most stable celestial time-keeper ever discovered.
Other stars of interest in Leo Minor includes the yellow supergiant 37 Leonis Minoris; the yellow giant 10 Leonis Minoris; the orange dwarf HD 87883; and the binary stars 20 Leonis Minoris and 11 Leonis Minoris.
The constellation may not contain any famous Messier objects, but it does have one of the strangest celestial objects to be found anywhere, namely:
– Hanny’s Voorwerp (Hanny’s Object) is an exceedingly rare type of “quasar ionization echo” that at the time of its discovery by Dutch amateur astronomer Hanny van Arkel in 2007 was considered by professional astronomers to be an “unidentified” object. Hanny’s Voorwerp is located close to the spiral galaxy IC 2497, and appears to be part of a gaseous streamer that partially surrounds that galaxy. It is only visible because a light source within IC 2497, believed to be a black hole, is illuminating a part of the streamer; much like a streetlight illuminates only a part of a dark street surface. The object is about 650 million light years distant, and is roughly the size of the Milky Way Galaxy, with a big central hole that spans about 16,000 light years.
There is evidence of large numbers of stars being formed in the part of Hanny’s Object that faces the illuminating galaxy, probably as a result of a huge outflow of gas from the galaxy that is colliding with gas and dust in the object. It is worth noting that the youngest of the newly formed stars are all several million years old.
– NGC 3432, also known as the Knitting Needle Galaxy, is located only about 3 degrees to the southeastward of the star 38 Leonis Minoris. At a distance of 42 million light years, this 11.67 magnitude edge-on galaxy is an easy target for most amateur telescopes.
Other objects of interest in Leo Minor includes the barred spiral galaxy NGC 3003 and NGC 3504; the spiral galaxies NGC 3344, NGC 3486 and NGC 3021; the barred lenticular galaxy NGC 2859; and a pair of interacting galaxies called Arp 107.
Two stars in the constellation, HD 87883 and HD 87883, each hosts one planet, although in the case of HD 82886, it is suspected that several planets smaller than the confirmed 1.3 Jupiter-mass planet may be orbiting the star.
This minor meteor shower with an uncertain maximum rate peaks between October 18th and October 29th, and can only be observed from the northern hemisphere. The Leo Minorids was only discovered in 1959, and is associated with the long period comet C/1739 K1 (Zanotti).