Leo

Leo

Leo

The Zodiac constellation Leo has

many interesting features including:• Bright Stars:

– Regulus (α Leonis), the lion's heart; Denebola (β Leonis); and (γ1 Leonis) Algieba.

• Galaxies:– Messier 65, Messier 66, Messier 95, and Messier 96 are the most famous, the

first two being part of the Leo Triplet. Plus there is another trio we’ll look at too.

• An asterism known as the Sickle

• Wolf 359– a star located approximately 2.4 parsecs or 7.7 light years from Earth.

– It is one of the nearest stars; only the Alpha Centauri system and Barnard's star are known to be closer.

– If you’re really a geek you also know this is were Captain Picard faced down the Borg.

• Gliese 436, a faint star in Leo about 33 light years away from the Sun, is orbited by one of the smallest extrasolar planets ever found.

• The carbon star (atmosphere contains more carbon than oxygen ) CW Leo (IRC +10216) is the brightest star in the night sky at the infrared N-band (10 μm wavelength).

Finding The Trio in Leo•Start by finding the

•bright star Regulus

Now move up to 3.5 mag Eta Leo

Notice the sickle shape asterism

that forms the head of Leo.

Finding The Trio in Leo•Start by finding the

•bright star Regulus

Now move up to 3.5 mag Eta Leo

Notice the sickle shape asterism

that forms the head of Leo.

As you follow the sickle place your

finder right in the middle of the next two

stars 2.6 mag Gami Leo and 3.4 mag Zeta Leo.

Gami Leo

•Zeta Leo.

NGC 3193 Mag 10.9

NGC 3190 Mag 12.1

NGC 3187 Mag 12.9

NGC 3185 Mag 12.0

The Trio in Leo

• This is actually a quartet, but the trio will fit in an eye piece.

• Commonly referred to as the Hickson 44

• In 1982 the Canadian Astronomer, Paul Hickson, using the red prints from the Palomar Observatory Sky Survey, published a catalog of 462 galaxies thought to exist within compact groupings. These groupings are now referred to as "Hickson Compact Groups" (HCG).

• The four dominant members of HCG 44 consists of three spirals and an elliptical galaxy, NGC 3190, 3193, 3185, 3187.

• Signs of tidal encounters between members of HCG 44 are present. NGC 3190, the dominant edge-on spiral shows considerable warping of its dustlane on the side nearer to NGC 3187.

• NGC 3187, also known as ARP 316a (Catalogue of Peculiar Galaxies) shows numerous tidal tails well above and below its disk plane.

• Signs of tidal interactions is significant in proving that the group is actually a compact system.

NGC 3193 Mag 10.9

NGC 3190 Mag 12.1

NGC 3187 Mag 12.9

NGC 3185 Mag 12.0

Photographs by Matthew T. Russell

NGC 3193 Mag 10.9

NGC 3190 Mag 12.1

NGC 3187 Mag 12.9

NGC 3185 Mag 12.0

Leo’s Regulus

• Lets now move back to bright Regulus

• Regulus is the alpha star which designates it as the brightest star in Leo and it is in fact one of the brightest stars in the night sky.

• At 140 times brighter then our Sun, Regulus has a surface temperature of over 12,000 degrees C and core temperature of 100 million degrees.

• Regulus is also the brightest star near to the ecliptic and is regularly occulted by the Moon.

• Though rare, Regulus may also be occulted by the planets Mercury and Venus.

• The last occultation of Regulus by a planet was on July 9, 1959, by Venus. The next will occur on October 1, 2044, also by Venus.

Leo’s Regulus• The Sun makes its closest approach to Regulus around

August 23 of each year. For most Earth observers, the heliacal rising (when it first becomes visible above the eastern horizon at dawn) of Regulus occurs in the first week of September.

• Every 8 years, Venus passes Regulus around the time of the star's heliacal rising, most recently in 2006.

• Regulus has about 3.5 times the Sun’s mass and is a young star of only a few hundred million years. It is spinning extremely rapidly, with a rotation period of only 15.9 hours, which causes it to have a highly oblate shape.

• This results in so-called gravity darkening: the photosphere at Regulus' poles is considerably hotter, and five times brighter per unit surface area, than its equatorial region.

• If it were rotating only 16% faster, centripetal force would overcome gravity and the star would tear itself apart.

Leo’s Regulus

• Regulus is a multiple star system composed of a hot, bright, bluish-white star with a pair of small, faint companions.

• The pair orbits the much-larger Regulus A with a period of over 130,000 years at a distance of some 4,200 AU.

• The companion pair have an orbital period of 2,000 years and are separated by about 100 AU.

Leo’s Regulus

• Leo I is a dwarf spheroidal galaxy in the Local Group of galaxies dominated by our Milky Way Galaxy and M31.

• Leo I is thought to be the most distant of the several known small satellite galaxies orbiting our Milky Way Galaxy. Regulus is located about 75 light years away, in contrast to Leo 1 which is located about 800,000 light years away.

Leo’s Regulus

Leo 1, 800,000 light years away.

Leo’s Regulus

• Regulus is Latin for 'prince' or 'little king'. The Greek variant Basiliscus is also used. In Arabic it is known as Qalb Al Asad, meaning 'the heart of the lion'.

• This phrase translates into Latin as Cor Leonis.

• Persian astrologers around 3000 BC knew Regulus as Venant, one of the four 'royal stars'.

• It was one of the fifteen Behenian stars (stars considered especially useful for magical applications) known to medieval astrologers, associated with granite, mugwort, and the kabbalistic symbol .

Leo – Other Stars

Beta Leonis is called "Denebola": the Lion's Tail.

Gamma Leonis is "Algieba", Arabic for forehead,

but more correctly named Juba, meaning mane.

notable binary with a slow orbit, sep. 4.4”

Zeta Leonis is "Aldhafera", the meaning is uncertain

Epsilon Leonis and mu Leonis

go under the name of "Al Ashfar",

the eyebrows.

Delta Leonis is "Zosma", a

Greek word meaning girdle.

Lambda Leonis is Alterf, apparently meaning "extremity".

It's located right at the tip of the lion's mouth.

Leo

R Leonis is a spectacular variable star

A red supergiant seems to pulse slowly

With a regular rhythm and becomes a

Naked eye object every 312 days.

Leo’s Wolf 359

Leo’s Wolf 359• Wolf 359 is a star located approximately 2.4 parsecs or

7.7 light years from Earth. It is one of the nearest stars; only the Alpha Centauri system and Barnard's star are known to be closer.

• It is an extremely faint red dwarf and too dim to be visible to the naked eye, with a visual magnitude of 13.54 it is a challenge in a amateur telescope.

• It is a flare star that undergoes random increases in luminosity because of magnetic activity on its surface.

• It is classified as a UV Ceti-type flare star, and has a relatively high flare rate. Observations with the Hubble Space Telescope (HST) detected 32 flare events within a two hour period

• The star was discovered using astrophotography by German astronomer Max Wolf in 1918.

• In 2001 this became the first star other than the Sun to have the spectrum of its corona observed from a ground-based telescope.

Leo’s Wolf 359

The Leo Triplet

• Now from Regulus we continue moving

down the body of the lion to 3.34 mag

Theta Leo.

The Leo Triplet

• Now move down about one quarter of the

distance past Theta Leo toward Denebola.

The Leo Triplet

• At a 90 degree angle to the line between

Theta and Denebola drop down again.

The Leo Triplet

• Here you’ll find the wonderful eye piece

full of three galaxies.

The Leo Triplet

• This small group of galaxies consists of the Messier objects M65 (NGC 3623) and M66 (NGC 3627) as well as the edge-on spiral NGC 3628.

• These three galaxies, the heart of the M66 group, form a beautiful and photogenic group which is frequently referred to as the Leo Triplett; Halton Arp has included this group as number 317 in his Catalogue of Peculiar Galaxies (M66 is also Arp 16).

• The triplet is lying at a distance of some 35 million light years.

German amateur Michael Weiland of the Interessengemeinschaft Astronomie at the University of Constance.

The Leo Triplet

• Chances are you will

not find this group

using the last photo.

• This is more like what

you will see in the eye

piece.

• With my 10” Meade I

use a 2X barlow and

5 mm eye piece.

Leonids Meteor Shower

• The Leonid meteor shower has produced some of the most spectacular meteor displays in history, but it unfortunately runs in a 33 year cycle.

• The Leonids start around November 13 and end November 21 with the peak being 17/18.

• The last enhanced peak was in 1998 - 2002, we are in a winding down phase that is normally 10 or so meteors an hour.

Leonids Meteor Shower

• The night of November 12-13, 1833, not only marks the discovery of the Leonid meteor shower, but it marks the actual birth of meteor astronomy. During the hours following sunset on November 12, some astronomers noted an unusual number of meteors in the sky, but it was the early morning hours of the 13th that left the greatest impression on the people of eastern North America. During the 4 hours which preceded dawn, the skies were lit up by meteors.

• Reactions to the 1833 display varied from the hysterics of the superstitious claiming Judgement Day was at hand, to just plain excitement by the scientific, who estimated that a thousand meteors a minute emanated from the constellation Leo. Newspapers of the time reveal that almost no one was left unaware of the spectacle, for if they were not awakened by the cries of excited neighbors, they were usually awakened by flashes of light cast into normally dark bedrooms by the fireballs.

Information from: http://meteorshowersonline.com/leonids.html

Leonids Meteor Shower

• At the time of the 1833 display, the true nature of meteors was not known for certain, but theories were abundant in the days and weeks which followed. The Charleston Courier published a story on how the sun caused gases to be released from plants recently killed by frost. These gases, the most abundant of which was believed to be hydrogen, "became ignited by electricity or phosphoric particles in the air." The United States Telegraph of Washington, DC, stated, "The strong southern wind of yesterday may have brought a body of electrified air, which, by the coldness of the morning, was caused to discharge its contents towards the earth." Despite these early, creative attempts to explain what had happened, it was D. Olmsted who ended up explaining the event most accurately.

Information from: http://meteorshowersonline.com/leonids.html

Leonids Meteor Shower• The interest of the astronomical world began focusing on the predicted return

of the Leonids as the decade of the 1860's began. Most important was H. A. Newton's examination of meteor showers reported during the past 2000 years. During 1863, he identified previous Leonid returns from the years 585, 902, 1582 and 1698. During 1864, Newton further identified ancient Leonid displays as occurring during 931, 934, 1002, 1202, 1366 and 1602. He capped this study with the determination that the Leonid period was 33.25 years and predicted the next return would actually occur on November 13-14, 1866.

• The year 1867, marked an important development in the understanding of the evolution of the Leonids. In1865, E. W. L. Tempel had discovered a 6th-magnitude, circular comet near the "Big Dipper." After an independent discovery was made by H. Tuttle in 1866, the comet took the name of "Tempel-Tuttle". Orbital calculations revealed the comet to be of short period, and, as 1867 began, T. von Oppolzer had more precisely calculated the period to be 33.17 years. Using observations from the 1866 Leonid display, U. J. J. Le Verrier computed an accurate orbit for the Leonids, and Dr. C. F. W. Peters, G. V. Schiaparelli, and von Oppolzer independently noted a striking resemblance between the orbits of this comet and Leonids.

Information from: http://meteorshowersonline.com/leonids.html

Leonids Meteor Shower• The study of the Leonid meteor shower took a notable turn in 1981.

D. K. Yeomans (Jet Propulsion Laboratory, California, USA) studied the relationship between the Leonids and the comet Tempel-Tuttle. He mapped out the dust distribution surrounding the comet by "analyzing the associated Leonid meteor shower data over the 902-1969 interval." He noted that most of the ejected dust lagged behind the comet and was outside its orbit, which was directly opposite to what was expected based on the way comets are known to operate. Yeomans suggested this indicated that the sun's own solar wind, as well as perturbations by the planets controlled the evolution of the Leonid stream.

• Concerning the occurrence of Leonid showers, Yeomans said "significant Leonid meteor showers are possible roughly 2500 days before or after the parent comet reaches perihelion but only if the comet passes closer than 0.025 AU inside or 0.010 AU outside the Earth's orbit."

• He added that optimum conditions will be present in 1998-1999, but that the lack of uniformity in the dust particle distribution still makes a prediction of the intensity of the event uncertain.

Information from: http://meteorshowersonline.com/leonids.html

Leo Mythology

• Leo was a much larger constellation in ancient

times. Its boundaries stretched to encompass the

constellation Cancer with M44 viewed as the big

cat’s whiskers, in this configuration Denebola was

its hindquarters. A wonderful curly tail had a tuft of

stars on the end which is now Coma Berenices.

• The Lion around 240 B.C., Leo was robbed of his

splendid tail. The astronomer-priest under Ptolemy

III chopped of the tail of Leo when they invented the

new constellation Coma Berenices (Berenice's Hair).

Leo Mythology

Leo Mythology• The Egyptians worshipped lion-gods which is evidence of the

importance this beast held in Egyptian life. During the dry season in

ancient Egypt, the lions of the desert came close to the valley of the

Nile when the river flooded, which would happen when the Sun was in

Leo. Some have interpreted this as the origin of the name of the

constellation.

• The Egyptians believed that the world was created at a time when the

Sun rose in Leo near the star Denebola. Leo was the emblem of the

fire and heat that nourished the land, intimately associated with all

the blessings that rained down from the greatest of the gods that

filled the world with light each day.

• It has been suspected that the great Sphinx represents both the Sun

and the constellation Leo.

• The Sphinx is shown, however, with the body of the Lion and the

head of Virgo, or some say perhaps a past queen.

Leo Mythology

Leo Mythology

• The Sumerians also saw this group of stars as a

lion. The form of the Lion was probably passed along to

the Babylonians, Greeks, Roman and others.

• The Persians knew Leo as Ser, to the Turk, Artan, to the

Syrians, Aryo, to the Jews, Arye, and to the Babylonians,

Aru, all meaning "Lion."

Leo Mythology

Hercules' first labor was to kill the Nemean lion, a fierce beast who descended to

Earth from the Moon in the form of a meteor landing on the Isthmus of Corinth.

The beast ravaged the countryside terrorizing people around the Nemean

forest. The lion had a hide so tough that neither spear nor arrow nor any other

weapon could pierce it. So well known was the beast that Hercules had no

trouble finding its lair, a cave with two entrances. As Hercules approached, the

lion showed itself and Hercules sped an arrow toward its heart. The arrow

merely bounced off and fell to the ground. Hercules now knew that arrows or

spears were useless against the beast. He then sealed off one of the entrances

to the cave and pursued the lion inside through the other entrance. So great

was his strength that Hercules seized the lion and strangled it to death by

ramming his fist down its throat. He then flung it over his shoulder and returned

to show King Eurystheus that he had fulfilled his first labor. The cowardly king

was terrified at the sight of the beast and fled. Hercules then skinned the lion

and used its tough hide as a protective shield in his next feat.

So angry was Hera at Hercules' success that she raised the soul of the lion

high into the sky, where today he can be seen as the constellation Leo, the Lion.

Leo Mythology• Approximately three thousand years before the Christian era carvings

and sculptures showed kings flanked with rampant lions. Indeed, the

archaeological evidence suggests that at about this time the lion had

already replaced an even earlier "sacred" symbol, the bull.

• It has been suggested that this transfer of power from a horned animal

to the lion was a change-over from a lunar-based to a solar-based

religion. That is, instead of drawing their inspiration from a night-time

symbol with a monthly cycle--a symbol which dealt with the fecundity

(ability to produce offspring ) of the earth and of its animals--the new

rulers identified with an animal of strength and power, and with a

heavenly body that ruled the day. Thus, as the bull had been identified

with the moon, the lion was now associated with the sun. To assert

this new religion, or new political structure, the lion was made to kill

the bull. Its place in the heavens was therefore critical.

Leo Mythology

• Thus Leo, slayer of Taurus, dominated the

summer skies, the time that the sun

passed through this constellation. Due to

precession, the sun currently passes

through Leo at the end of summer, from

mid-August through mid-September.

Leo Mythology

• The Babylonians also saw a great dog in the

stars of Leo. Ferocious guard dogs to

protect men, beasts and goods were

important to the Babylonians. Every caravan

had a number of huge dogs.

Leo Mythology

Leo Mythology• The Taulipang Indians of northern

Brazil see Tauna, the God of

Thunder and Lightning.

Remember in equatorial regions

Leo rises nearly 90 degrees to the

horizon, Tauna stands upright in

the sky. In this image the sickle is

the arm holding the club, Regulus

is the head while Denebola marks

the left foot.

• During heavy thunder storms the

Indians say Tauna is bashing the

clouds with his club making

lightning flashes and the rumble of

thunder.

Leo Mythology

• The Tukano, Kobeua and Siusi Indians of

northern Brazil saw Leo as a crayfish.

• Amazingly Regulus is ignored in the crayfish,

the left claw reaches into Virgo and Coma

Berenices the right.

Leo Mythology

Leo Mythology

• High in the Arctic of Siberia the Chukchee

saw a sleeping women in what we say is the

lion’s chest and head.

Leo Mythology

Leo Mythology

• In Chinese mythology the

question mark was Hien-

youen the Rain Dragon. It

was seen as a symbol of life

giving power of water.

• China is often the hardest hit

by times of drought with a

history of some of the

greatest. When Hien-youen

appeared in the night sky the

time had come to start

ceremonies of the Rain

Dragon.

Leo Mythology

The End