Date: February 3, 2011

Title: Backyard Astronomy in Leo

Podcaster: Martin Fanning

Description: Here’s a quick overview of the constellation Leo and some of the things you can see through a backyard telescope.

Bio: Martin Fanning lives in Daphne, Alabama with his wife and three kids. Martin can’t remember a time he wasn’t interested in space and astronomy. Martin typically observes the sky from his backyard and is dabbling in astrophotography with a DSLR. He especially enjoys sharing the beauty of the night sky with kids.

Today’s sponsor: This episode of “365 Days of Astronomy” is sponsored by Steven Krisocki and is dedicated to my father, who introduced me to the concepts of light pollution and light years, the Apollo Project, which introduced me to the concept of space flight, and to Dr. Pamela Gay and Fraser Cain, who introduced me to astronomy podcasts.

Additional sponsorship for this episode of “365 Days of Astronomy” has been provided by Neil Christie. Those who can Podcast, those who can’t donate.

Transcript:

Hi, I’m Martin Fanning, an amateur astronomer living in Southern Alabama. I am a member of the Mobile Astronomical Society and our club meetings usually include a presentation on a constellation. This month, I have chosen Leo, the Lion for my talk. For today’s Three Hundred Sixty-five Days of Astronomy, I thought I would give you a flavor of the types of things I’ll be presenting to the club tonight.

Leo, the Lion is one of the brighter and more prominent constellations in the sky. Many people are familiar with Leo, simply because it is one of the signs of the zodiac. That means it is one of the constellations that falls along the path that the sun takes across the sky.

This group of stars has represented a lion for many cultures. The Greek mythology of Leo comes from the story of Hercules and his twelve labors. The Nemean Lion had a hide that was impervious to attack. After attempts with arrows, sword and club had failed, Hercules resorted to wrestling and eventually strangled the beast. He then used the hide as armor. To commemorate the battle, the lion was placed among the stars.

Leo’s major stars are easy to spot. The head of the lion is represented by a group of stars that look like a backwards question mark with the bright star, Regulus, as the dot at the bottom. The lion’s back extends to the east where a wide triangle of bright stars represents his back leg.

Regulus is the brightest star in Leo and represents the heart of the lion. It is a “B” class blue-white main sequence star with about three and a half times the mass of our sun. Regulus lies about seventy-seven light years away from us and has a pair of faint companions.

Denebola is the second brightest star and represents the tail of the lion. It is an “A” class white main sequence star which is about thirty-six light years away.

Algebia is a very nice binary star system where the two components differ in brightness by just one magnitude. The brighter of the two stars is an orange giant star. The other is yellow in color like our sun, but it is also a giant star. Their separation is 4.6 arc minutes, which should be easy to separate in most backyard telescopes. The stars orbit around each other with a period of over six hundred years.

Other nice double stars in Leo include 49 Leonis, which is a very close binary and may be tough to split, and 54 Leonis, which is a bit farther apart than Algebia and should be no problem.

One of the many variable stars in Leo is R Leonis. It is a Mira-type variable star which varies in brightness from fouth magnitude to eleventh magnitude over a three hundred ten day period. That’s almost six hundred times change in brightness. The star is a very deep red color and the variation in brightness is due to pulsation of the stars surface. The next time it is at maximum brightness will be around May 2011, so this a great time to start observing this star and track it as it gets brighter.

One other star of interest is Wolf 359, which is one of the closest stars to us after the Alfa Centauri triple star system and Barnard’s star. Wolf 359 is a red dwarf star which is 7.8 light years away from us. Even though it is so close it is hard to see because it is so faint. With a magnitude of 13.5, slightly brighter than Pluto, it would take an eight inch telescope and dark skies to catch a glimpse of this close neighbor.

Most of the notable deep sky objects in Leo are galaxies. Leo is home to five Messier objects, all of which are galaxies.

M65 and M66 along with NGC 3628 form a small triangle of galaxies called the Leo Triplet. This group sits just below Leo’s back leg. This group of galaxies is about 35 million light years away. M66 is the brightest of the three spiral galaxies with a magnitude of 9.0. M65 is located just 21 arc minutes away is slightly fainter with a magnitude of 9.2. NGC 3628 is fainter still and is seen edge on to us and is a bit farther away from the other two, about 35 arc minutes.

M96 is a spiral galaxy and at magnitude 9.2 is the brightest member in the Leo I group of galaxies. This group of galaxies is also around 35 million light years away. Other prominent members of this group are M95, M105 and NGC 3384. M95 is a barred spiral, which at magnitude 9.8 is one of the fainter Messier objects. M105 is an elliptical galaxy with a magnitude of 9.3. Very close to M105 is another elliptical galaxy NGC 3384 with a magnitude of 9.9.

Another galaxy worth looking for is NGC3626. This is a spiral galaxy located near Leo’s hip and is about 70 million light years away. Because of the greater distance, it is smaller and fainter than the other galaxies I have mentioned, but is a compact galaxy so its surface brightness is similar.

One more galaxy, located near Leo’s head is NGC 2903. It is a spiral galaxy which lies a little closer to us than the rest of these galaxies. It is brighter overall with a magnitude of 8.8, but has a lower surface brightness, making it harder to see.

All of these galaxies were pretty easy to spot in my 8 inch telescope from my suburban backyard.

Leo begins climbing above the horizon shortly after sunset in early February and should be entirely above the horizon by 8PM, so it will be ideally positioned for viewing. So, take some time over the next couple of months and enjoy the sights of Leo, the Lion.

End of podcast:

365 Days of Astronomy
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