Leo: the Astronomy, Mythology and Challenge

Dear Diary…

Part 1: The Astronomy

  

Leo, Latin for Lion, is one of the 88 constellations delimiting our skies. This constellation is on Cancer’s west and Virgo’s East, it’s surrounded by Leo Minor, Coma Berenices, Sextans and Hydra. It’s very easy to spot its alpha star of 1,34 magnitude, Regulus: either by going from Ursa Mjor or from Gemini’s Pollux and Castor.

Constellation of Leo

This constellation is also one of the 12 zodiac constellations as it’s situated along the ecliptic, and it’s home to many interesting stars and deep sky objects.

Getting to Regulus From Gemini
 

Getting to Regulus from Ursa Major

Here’s a small table of its main stars:

	Name	Magnitude	Distance (ly)	Type
α Leonis	Regulus	1.34	79.3	Four-star system
β Leonis	Denebola	2.23	35.9	Main sequence star
γ Leonis	Zosma	2.58	58.4	Main sequence star
δ Leonis	Algieba	2.61	130.2	Binary star system
ϵ Leonis	Ras Elased Australis	3.12	246.7	Bright giant
θ Leonis	Chort	3.41	165.1	Main sequence star
η Leonis	Al Jabbah	3.58	1269.1	Supergiant

Stars of the Leo constellation

Let’s discuss few of its deep sky objects:

            Probably one of the most famous deep sky objects credited to Leo is the Leo Triplet of Galaxies which is three spiral galaxies that appear close to each other when viewed from Earth: M65, M66 and NGC3628.

Clockwise from top left NGC3628, M65, M66

M95 and M96 form an other interesting group of Leo galaxies. Both pairs of M95, M96 and M65, M66 are some 30 million light years away. M95 is believed to be home to a recent supernova that occurred at the beginning of 2012.

M95 (left) and M96 (right)

      The Leonids meteor shower occurs during mid-November with its peak scoring 10 to 20 meteors per hour. These showers are debris from the Tempel-Tuttle comet which orbits the Sun every 33 years. However, three times a century, the shower has a quick burst of more than 1,000 meteors per hour, definitely not an event to miss.

Leonids Meteor Shower Radiant Point

Part 2: The Mythology

            In Roman mythology, Leo was a monster that ate the people of Nemea. Hercules choked the lion, Leo, to death using his bare hands, then skinned it and used its pelt as a cloak. He also donned the lion’s head as his helmet. This was Hercules’ first episode of his twelve labors, a penance that he had to undergo.

Hercules fighting the Nemean Lion

            In Egyptian mythology, Leo was not a mythical beast, quite one the contrary, the creature was regarded as a savior, the Egyptians relied on the Nile river to flood every year and nurture the land forthe harvest, an event so crucial to the survival of the Egyptians that festivals were held to the gods, including Leo, regularly in hopes that the inundation would be good.

The Great Sphinx of Giza

             Statues depicting lion heads can be found along the Nile. The Sphinx directly faces the East. On the vernal equinox, it witnesses the rising of the constellation Leo (the Lion) and the Sun.

Part 3: The Challenge

            This is the stargazer’s challenge.Think you’re good? Try to spot a flare star that has a magnitude of only 13.53: Wolf 359.

Look for Wolf 359

            Catalogued as CN Leonis, this red dwarf in the constellation of Leo that’s 7.78 light years away, its luminosity is barely 0.0000187 the luminosity of the Sun and it’s about the size of Jupiter. If our Sun were to be replaced by Wolf 359, an observer on Earth would need a telescope to see its spherical shape. Happy stargazing!

Red Dwarf Wolf 359