All About The Leo Minor Constellation

Leo minor in Latin means “the smaller/little lion.” Johannes Hevelius, a polish astronomer created a catalog of 1,564 stars and a celestial atlas listing several constellations. Leo Minor was one of the constellations he created from 18 stars between Ursa Major and Leo.

Leo Minor is a faint and small constellation occupying only 232 square degrees of the sky. It ranks 64th among the International Astronomical Union (IAU) 88 constellations.

The bright stars in the constellation have orange and faint yellow-white compositions. An interesting fact about the constellation is that it includes two planetary system stars and a deep sky object, a quasar ionization echo called Hanny’s Voorwerp. It appears as a bright blob close to spiral galaxy IC 2497, believed to contain remnants of a small galaxy 100,000 years ago.

Leo Minor Location

Leo minor can be spotted in the northern celestial hemisphere about 10 hours right ascension and 22.84° to 41.43° declination. The coordinates are 10h 00m 00s, +35° 00′ 00.″

Leo Minor is located between the recognizable Ursa Major to the north, Cancer to the southwest, Leo to the south and Lynx to the west.

By Till Credner - Own work: AlltheSky.com

Mythology

At their time, Ptolemy and Aratus considered the region that is currently occupied by Leo Minor as empty. This is the reason we do not find any mythologies associated with the constellation. In addition, Leo Minor is a new constellation, founded by Johannes Hevelius around 1690 so it naturally doesn’t have any associations with Greek or Roman mythological characters.

Major Stars in The Leo Minor Constellation

Leo Minor has three main stars in the constellation that are brighter than the magnitude 4.5. There are 34 Bayer/Flamsteed stars and 3 stars with planets. Here are some of the major stars in the Leo Minor constellation.

46 Leonis Minoris (Praecipua)

Praecipua is the brightest star of the constellation. It comes from Latin meaning “the chief”, which is believed to have originally referred to 37 Leonis Minoris. Praecipua was originally intended to become part of the Alpha (α) designation but it was found to be omitted from the catalogue of astronomer Francis Baily.

It is located at 10h right ascension and +34° declination. The absolute magnitude (MV) of Praecipua is +1.45 and the apparent visual magnitude is 3.83.

46 Leonis Minoris is located 95 light years away from the Earth and is 8.5 times the size of the Sun. It is visible as a red clump −clustering of red giants which are cool stars that have undergone a helium flash and are now fusing helium in their cores.

Beta Leonis Minoris (β Leonis Minoris)

Beta Leonis Minoris is a binary star and the only star in the constellation with a Bayer designation (identified by a Greek or Latin letter).

It has an apparent visual magnitude of 4.1 and absolute magnitude of +0.85. Beta Leonis Minoris has 7.8 times the radius and 36 times the luminosity of the Sun. It lies about 154 light-years away from the Solar System.

The primary star is of spectral class G8 which is a red clump giant fusing helium in its core. The secondary is a yellow-white main sequence star of spectral type F8 subgiant which is hotter than the sun

21 Leonis Minoris

21 Leonis Minoris is the third brightest star in the constellation. It is a faint star with an apparent magnitude of about 4.5. The star is 92.1 light years away from the Earth. 21 Leonis Minoris is known for its fast rotation - spinning on its axis in less than 12 hours. It is a white-main sequence star with a projected rotational velocity of 155 km/s.

Based on its Spectral type A7V, the surface temperature of 21 Leonis Minoris is 7,500-10,000K, according to Harvard Spectral Atlas.

Deep Sky Objects in Leo Minor Constellation

A unique and mysterious deep sky object in the Leo Minor constellation is called Hanny's Voorwerp (HsV). The name is Dutch for “Hanny’s Object” based on the discovery of a school teacher named Hanny van Arkel who observed an object in the sky that she was unsure of how to classify. The object or “Voorwerp” appeared near the spiral galaxy IC 2497 as a bright blob.

Hanny's Voorwerp is about the size of a small galaxy. Observations made with radio telescopes and the Hubble Space Telescope have shown a weak nuclear activity in the galaxy.

There are many hypotheses around the “Voorwerp” and what it signifies. According to one hypothesis, the HsV is thought to consist of remnants of a small galaxy as a result of a radiation event that occurred 100,000 years ago.

In 2020, researchers at EVN and MERLIN came up with a hypothesis of possible explanation of the object. They proposed that the light source could be either from a black hole at the center of IC 2497 or from the interaction between an astrophysical jet and the gas around IC 2497.