Some Facts You Must Know about Constellation Leo

Leo is considered one of the constellations of the zodiac; it is the biggest constellation in the sky. This constellation lies between Cancer the crab to the West and to the East is Virgo the maiden. Till today Leo remains one of the modern constellations and it can be easily recognized because of its bright stars and a distinctive shape that is possessed by it. Leo represents the Lion.

Location: Leo being the 12th largest constellation occupies an area of 947 square degrees. It is being located in the 2nd quadrant of the Northern Hemisphere.

Facts:  the constellation Leo contains 5 Messier objects namely:

  • Messier 65 (M65, NGC3623)
  • Messier 66 (M66, NGC3627)
  • Messier 95 (M95, NGC3351)
  • Messier 96 (M96,NGC3368)
  • Messier 105 (M105, NGC3379)

It consists of 11 stars with known planets.


Myth: Leo is considered to be the oldest constellation in the sky.

In Babylon the people regarded the star Regulus as “the star standing at the breast of the Lion” or the King Star. The constellation and its brightest star were knowing in the ancient cultures.  The Greeks consider Leo the beast that was killed by Heracles during the first of the twelve labours. The Lion was placed among the constellation because it was considered the king of beasts. The Lion lived in a cave, and used to kill local inhabitants but no one could kill it because its skin was such that no weapon could pierce its skin. Heracles could not kill the Lion with any kind of weapons so he trapped it in its cave and choked it to death.


Major stars in constellation Leo:

  • Regulus (Alpha Leonis)

It is the brightest star in the constellation Leo and the 22nd brightest star in the sky. It has a magnitude of 1.35.  Regulus consists of two pairs of stars thus it is a four star system. Alpha Leonis is considered to be the closes bright star to the ecliptic. Regulus cab be best seen in the evening in the late winter and spring, in the Northern Hemisphere. When the star lies too close to the sun, that is the only time of the year when it cannot be seen on either sides.

  • Denebola ( Beta Leonis)

It is the second brightest star in constellation Leo and is also the 61st brightest star in the sky. It has a magnitude of 2.113 and it can be very easily seen without the use of binoculars.  Denebola is said to have 73% more mass than the Sun. Beta Leonis is a young star with an estimated age of less than 400 million years. It is a rapid rotator with a bulge at its equator. Its rotational velocity is 128 km/s. Denebola has excess of strong infrared so it might have debris disk of dust in its orbit.





  • Algieba ( Gamma Leonis)

Algieba is a double star in the constellation Leo. This system has a combined magnitude of 1.98. It is easy to observe under a small telescope which is in good condition. It will appear clearly as a double star with orange red and greenish yellow components. Algieba the double stars, Adhafera (Zeta Leonis) and Al Jabbah (Eta Leonis) are sometimes collectively known as Sickle.

  • Zosma (Delta Leonis)

This is another rapid rotator in constellation Leo, with a rotational velocity of 180 km/s. It has an oblate shape and also has an equatorial bulge. It has a visual magnitude of 2. 56.  Delta Leonis is considered to be little more hotter and larger than the sun. It’s said that in another 600 million years this will be a red giant.

  • Chort (Theta Leonis)

this is another white main star. Theta Leonis is visible to the naked eye. It has a magnitude of 3. 324.  The estimated age of Theta Leonis is 550 million years, which signifies that this could be younger than the sun. Its rotational velocity is 23km/s.


The deep sky objects that are there in constellation Leo:

  • Messier 65 (M65, NGC3623) : It is the spiral galaxy in constellation Leo. Its magnitude is said to be 10.25. there is no much of dust and gas that is there in the galaxy. There are no much stars that are being formed here. The stars in this galaxy are considered to be old. Recently it was seen that there were some star burst activity which proves that the galaxy has been interacting with some other objects.
  • Messier 66 (M66, NGC3627) : This is an intermediate spiral galaxy in constellation Leo. The galaxy has a visual magnitude of 8.9, it has been noted for its bright star clusters and its dust lanes. This is also considered to be a part of the Leo Triplet along with M65 and NGC3628.
  • Messier 95 (M95, NGC3351) : This is the barred spiral galaxy in the Leo constellation. Its visual magnitude is measured as 11.4. An almost perfect circle around the galactic centre before it spreads out is formed by the spiral arms. This than forms a mane like structure. Its most amazing feature is it’s golden blazing core. It also consists of a nuclear star forming ring.
  • Messier 96 (M96,NGC3368) : this is yet another immediate spiral galaxy which is located in constellation Leo. It has a magnitude of 10.1. M96 has some graceful imperfections which have resulted from the gravitational pull from the other members of the group.  The imperfections could also be due to the past galactic encounters. The galaxy also has a double barred spiral with a small inner bulge through the centre along with an outer bulge.  There are emissions let out by the galaxy at its central region which has resulted in a super massive black hole in its core.
  • Messier 105 (M105, NGC3379) : This is an elliptical galaxy in the constellation Leo. The magnitude of Messier 105 is said by 10.2. researches show that the galaxy has a super massive hole at its centre.



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