Want to stay on top of all the space news? Follow @universetoday on TwitterConstellation Leo is given the Latin name for a lion. This constellation is framed by Cancer on the west and Virgo to the east. It can be found at right ascension 11h and declination +15° in the NQ2 quadrant. It contains 92 Bayer/Flamsteed stars. Nine of those stars have their own planets. The brightest star is Regulus and the star closest to Earth is Wolf 359 at 7.78 light years. The constellation occasionally seems to be the center of a meteor shower. The meteors are called Leonids.
A constellation is a group of stars visible within a particular region of the night sky. The word constellation also refers to the region in which a specific group of stars appears. Astronomers have divided the sky into 88 areas, or constellations. Some smaller groups of stars within a constellation are called asterisms. For example, the Big Dipper is an asterism that lies in the constellation Ursa Major. Leo contains as asterism called the Sickle. Regulus, n Leonis, y Leonis, Adhafera, Ras Elased Borealis, and Ras Elased Australis form this asterism.
Leo contains a couple of other notable stars. Wolf 359 is most notable for being one of the closest stars in the universe to Earth at 7.78 light years. Gliese 436 is only 33 light years from the Sun is orbited by a planet with about the same mass as Neptune. The carbon star CW Leo (IRC +10216) is the brightest star in the infrared N-band. Other notable features of Leo include the galaxies Messier 65, Messier 66, Messier 95, and Messier 96. The Leo Ring, a cloud of hydrogen and helium gas left over from the Big Bang, is found in orbit of two galaxies within this constellation.
The Leonids are a prolific meteor shower associated with the Tempel-Tuttel comet. They get their name because the meteors appear to radiate from Leo. They are famous for being a fast moving stream which comes close to or crosses the path of the Earth and impacts the Earth at 72 km/s. Leonids are well known for having bright meteors which may be 9mm across and have 85g of mass. They can punch into the atmosphere like a car hitting at over 90 kph. A single shower may deposit 12 or 13 tons of particles across the entire planet.
Here is the page on NASA’s site that links to their information on Leo. We have two great related articles here on Universe Today: one is about the constellation Leo and the other is about the Leonids. Astronomy Cast offers a good episode about all of the constellations in the night sky.