IAU Constellation (LMi) · Genitive: Leonis Minoris · Northern Sky

Leo Minor (The Lesser Lion) Sky Guide

Leo Minor IAU constellation (232 sq deg, rank 64): April spring sky between Leo and Ursa Major, led by +3.83 Praecipua (46 LMi) and Hanny's Voorwerp.

Solid-Angle Area232 sq deg (Rank #64 of 88)
Best Evening MonthApril
Visibility Latitudes+90° to −45°
Brightest StarPraecipua (46 Leonis Minoris) (+3.83)

Sky Navigation & Astrophysical Context

Tucked into 232 square degrees of the spring sky between the Sickle of Leo to the south and the hind paws of Ursa Major to the north, Leo Minor was created by Johannes Hevelius in 1687 to populate the unformed fourth-magnitude stars between the two great beasts. Its narrow triangular outline is formed by 46 Leonis Minoris (Praecipua, +3.83), Beta Leonis Minoris (+4.20), and 21 Leonis Minoris (+4.49).

Uniquely among the 88 IAU constellations, Leo Minor has no star designated 'Alpha': when the English astronomer Francis Baily assigned Greek Bayer letters in his 1845 British Association Catalogue, he inadvertently skipped Alpha and labeled only Beta Leonis Minoris (+4.20, a close spectroscopic/interferometric G8 III + F8 IV binary with a 38.6-year period), leaving the K0+ III-IV orange giant 46 Leonis Minoris (Praecipua, meaning 'The Chief Star' in Hevelius's catalog, V = +3.83) with only its Flamsteed number.

In extragalactic astronomy, Leo Minor gained worldwide fame in 2007 when Galaxy Zoo citizen scientist Hanny van Arkel discovered 'Hanny's Voorwerp' next to the spiral galaxy IC 2497—a 100,000-light-year-wide green ionization echo of gas still glowing in doubly ionized oxygen ([O III]) from a quasar beam in IC 2497 that switched off ~200,000 years ago—alongside bright observable galaxies NGC 3344, NGC 3432, and NGC 3504.

Bordering IAU Constellations: Ursa Major, Lynx, Cancer, Leo.

Equatorial Center Position & Transit Altitude

Leo Minor is centered near Right Ascension 10h 14m 24s, Declination +32° 07′ 48″ (The Lesser Lion (Lion Cub)).

J2000 Equatorial Sky Position (Leo Minor) +90° 0° −90° 24h 12h RA 0h Peak Meridian Altitude 82° 40°N Lat 28° 30°S Lat RA: 10h 14m 24s Dec: +32° 07′ 48″ Epoch: J2000.0 · 232 sq deg (Rank #64) First-party vector diagram derived from IAU / CDS SIMBAD / Gaia DR3 astrometry.

Practical Star-Hopping & Observing Tips

  • Look midway between the Sickle of Leo and the southern pair of Ursa Major's hind-paw leaps (Xi and Nu Ursae Majoris) to trace the triangle of 46, Beta, and 21 Leonis Minoris.
  • Aim a 150 mm+ telescope 3.5° southwest of 41 Leonis Minoris to view the face-on ringed spiral galaxy NGC 3344 (V = +9.9) framed behind two foreground Milky Way stars.
  • Observe the long-period Mira variable R Leonis Minoris (2.5° west of Beta LMi) when its 372-day pulsation brings it up to visual magnitude +6.3 in binoculars.

Notable Celestial Objects in & Near Leo Minor

Cataloged Stars and Deep-Sky Objects Associated with Leo Minor
ObjectFamilyClassificationRA (J2000)Dec (J2000)Min. Instrument
Mizar & Alcor (Zeta Ursae Majoris System)multiple-starsSextuple A-type stellar system (first telescopic & first spectroscopic binary)13h 23m 55.54s+54° 55′ 31.3″Naked eye for Mizar–Alcor; any 40–60 mm telescope at 40× for Mizar A–B
Beehive Cluster (Messier 44 Praesepe)open-clustersOpen star cluster08h 40m 24.00s+19° 40′ 00.0″Naked eye; spectacular in 10×50 binoculars

Scientific Sources Cited