STARS AND CONSTELLATIONSPRESENTED BY: G11-20JOHN NINO GARCIA RAIN ANGELA CRUZPRESENTED TO:MRS. TADEO

STARS Stars are cosmic energy engines that produce heat,

light, ultraviolet rays, x-rays, and other forms of radiation. They are composed largely of gas and plasma, a superheated state of matter composed of subatomic particles.

No one knows how many stars exist, but the number would be staggering. Our universe likely contains more than 100 billion galaxies, and each of those galaxies may have more than 100 billion stars.

Appearances of Stars Some stars have always stood out from the rest.

Their brightness is a factor of how much energy they put out–known as luminosity–and how far away from Earth they are.

Stars in the heavens may also appear to be different colors because their temperatures are not all the same. Hot stars are white or blue, whereas cooler stars appear to have orange or red hues.

Stars may occur in many sizes, which are classified in a range from dwarfs to supergiants. Supergiants may have radii a thousand times larger than that of our own sun.

Main Sequence Stars - Young StarsThese stars' energy comes from nuclear fusion, as they convert Hydrogen to Helium.

Most stars (about 90%) are Main Sequence Stars. For these stars, the hotter they are, the brighter they are. The sun is a typical Main Sequence star. 

DWARF STARSDwarf stars are relatively small stars, up to 20 times larger than our sun and up to 20,000 times brighter. Our sun is a dwarf star. 

YELLOW DWARFYellow dwarfs are small, main sequence stars. The Sun is a yellow dwarf. 

RED DWARFA red dwarf is a small, cool, very faint, main sequence star whose surface temperature is under about 4,000 K. Red dwarfs are the most common type of star. Proxima Centauri is a red dwarf. 

Life Cycle of Stars Stars are born in nebulae. Huge clouds of

dust and gas collapse under gravitational forces, forming protostars. These young stars undergo further collapse, forming main sequence stars. 

Stars expand as they grow old. As the core runs out of hydrogen and then helium, the core contacts and the outer layers expand, cool, and become less bright. This is a red giant or a red super giant (depending on the initial mass of the star). It will eventually collapse and explode. Its fate is determined by the original mass of the star; it will become either a black dwarf, neutron star, or black hole. 

Giant and Supergiant Stars - Old, Large Stars 

RED GIANTA red giant is a relatively old star whose diameter is about 100 times bigger than it was originally, and had become cooler (the surface temperature is under 6,500 K). They are frequently orange in color. Betelgeuse is a red giant. It is about 20 times as massive as the Sun about 14,000 times brighter than the Sun, and about 600 light-years from Earth. 

BLUE GIANTA blue giant is a huge, very hot, blue star. It is a post-main sequence star that burns helium. 

SUPERGIANTA supergiant is the largest known type of star; some are almost as large as our entire solar system. Betelgeuse and Rigel are supergiants. These stars are rare. When supergiants die they supernova and become black holes. 

Faint, Virtually Dead Stars: 

WHITE DWARFA white dwarf is a small, very dense, hot star that is made mostly of carbon. These faint stars are what remains after a red giant star loses its outer layers. Their nuclear cores are depleted. They are about the size of the Earth (but tremendously heavier)! They will eventually lose their heat and become a cold, dark black dwarf. Our sun will someday turn into a white dwarf and then a black dwarf. The companion of Sirius is a white dwarf. 

BROWN DWARFA brown dwarf is a "star" whose mass is too small to have nuclear fusion occur at its core (the temperature and pressure at its core are insufficient for fusion). A brown dwarf is not very luminous. It is usually regarded as having a mass between 1028 kg and 84 x 1028. 

NEUTRON STARA neutron star is a very small, super-dense star which is composed mostly of tightly-packed neutrons. It has a thin atmosphere of hydrogen. It has a diameter of about 5-10 miles (5-16 km) and a density of roughly 10 15 gm/cm3.

PULSARA pulsar is a rapidly spinning neutron star that emits energy in pulses. 

BRIGHT STARS AND THE STARS CLOSEST TO EARTH

LUMINOSITYLuminosity is the total brightness of a star or galaxy. 

ABSOLUTE AND APPARENT MAGNITUDE

Apparent magnitude is a measure of the brightness of a celestial object as seen from Earth. The lower the number, the brighter the object. Negative numbers indicate extreme brightness. The full moon has an apparent magnitude of -12.6; the sun's is -26.8. We can see objects up to 6th magnitude without a telescope. Apparent magnitude is abbreviated m. This system of rating the brightness of celestial objects was developed by the Greek astronomer Hipparchus in 120 B.C. 

Absolute magnitude is a measure of the inherent brightness of a celestial object. This scale is defined as the apparent magnitude a star would have if it were seen from a distance of 32.6 light-years (10 parsecs). The lower the number, the brighter the object. Negative numbers indicate extreme brightness. 

Rank Star Absolute Magnitude Apparent Magnitude Distance from Earth(light-years)

. The Sun +4.8 -26.72 .1 Sirius (in Canis Major) +1.4 -1.46 8.62 Canopus (in Carina) -2.5 -0.72 74

3 Rigel Kentaurus (Alpha Centauri) (in Centaurus) +4.4 -0.27 4.3

4 Arcturus (in Boötes) +0.2 -0.04 345 Vega (in Lyra) +0.6 0.03 256 Capella (in Auriga) +0.4 +0.08 417 Rigel (in Orion) -8.1 +0.12 9008 Procyon (in Canis Minor) 2.8 +0.38 119 Archenar (in Eridanus) -1.3 +0.46 75

10 Betelgeuse (in Orion) -7.2 +0.50 1,50011 Hadar (in Centaurus) -4.3 +0.61 30012 Altair (in Aquila) +2.3 +0.77 1713 Acrux (in Crux) -3.8 +0.79 27014 Aldebaran (in Taurus) -0.2 +0.85 6515 Antares (in Scorpius) -4.5 +0.96 400... ... ... ... ...20 Deneb (in Cygnus) -7.2 +1.25 1,500-- Proxima Centauri (in Centaurus) +15.5 +11.05 (var.) 4.3

SOME BRIGHT THAT CAN BE SEEN FROM EARTH ANTARES

(Alpha Scorpii) Antares (meaning "Rival of Mars") is the brightest star in Scorpius, one of the constellation in the zodiac. Antares is a M1.5Iab variable red supergiant star that is about 520 light-years from Earth and is about 230 times as big as the Sun. This incredibly massive, old, low-temperature (3500 K) star is the 15th brightest star in the sky; it has a visual (apparent) magnitude of +0.96 (var.) and an absolute magnitude of -5.2. ARCTURUS(Alpha Boötis) Arcturus is the brightest star in the constellation Boötes (the herdsman). It is a red giant (spectral type K1.5IIIp) that is the fourth brightest star in the sky. Arcturus is 34 light-years from Earth. It has an apparent magnitude of -0.04 and an absolute magnitude of 0.2. 

BETELGEUSE(pronounced "beetle juice") Betelgeuse (alpha Orionis) is the second-brightest star in the constellation Orion and one of the brightest stars in the sky. It is a supergiant star, reddish in color, and over 600 million miles in diameter (almost 1,000 times bigger than the Sun but cooler than the Sun). If Betelgeuse were at the center of our Solar System, it would extend beyond the orbit of Jupiter. It is 520 light-years from Earth. It is a variable star, varying in magnitude from 0.3 to 1.2 over a period of about 7 years, averaging about 0.70. It is the only star (other than our sun) for which we have surface images. 

DENEBDeneb (which means "tail" in Arabic) is the brightest star in the constellation Cygnus (the swan); Deneb is also referred to as alpha Cygni, and is the tail of the swan. This young, bright, white supergiant star is about 1,500 light years away. Deneb is about 60,000 times more luminous than the sun!

POLARISPolaris (alpha UMi) is the current pole star for the Northern Hemisphere; it is 1 degree from the exact Northern celestial pole. In 1780, Sir William Herschel discovered that Polaris was a double star with a faint companion star. Polaris is a blue-green Cepheid variable star (its size brightness changes periodically, with period of 3.969778 days; it varyies between mag 1.92 and 2.07). Polaris has a relatively dim companion star (9th magnitude). Polaris' distance from Earth has been estimated to be from 360 to 820 light years. At its brightest, Polairs is about 6,000 to 10,000 times brighter than our Sun. It is the larger star at the end of the handle of the Little Dipper (Ursa Minor). Polaris is also called the Lodestar or the Cynosure.ORION

Orion, also known as "The Hunter," is a constellation in the zodiac. The brightest stars in Orion are Rigel, Betelgeuse, and Bellatrix. The Horsehead Nebula and the nebulae M42 and M43 are also in this constellation. 

RIGELRigel (beta Orionis) is the brightest star in the constellation Orion and one of the brightest stars in the sky. It is a blue (very hot) supergiant, over 60 million miles in diameter (almost 100 times bigger than the sun). It is more than 50,000 times more luminous than the Sun. It has an absolute magnitude of -7.1 and an apparent magnitude of +0.12. It is over 900 light-years from Earth.SIRIUSSirius (meaning "scorching" in Greek), also known as the dog star, is the brightest star in the sky (except for the sun). It is in the constellation Canis Major (The Great Dog). Sirius is a main sequence star that is about 70 times more luminous than the sun. It is about 8.6 light-years from Earth. It has an apparent magnitude of -1.46 and an absolute magnitude of +1.4. Sirius has a companion star (called the Pup), which is a white dwarf.

NORTH STARThe north star is a star that is located almost due north and is useful for navigation. Polaris is currently the pole star of the Northern Hemisphere.

VEGAVega (Alpha Lyrae) is a very bright star in the constellation Lyra. It is also known as the Harp Star and Fidis. Vega is the 5th brightest star in the sky and is pale blue. It is about 25 light years from Earth. Its spectral type is A0Va. A disk of dust surrounds Vega, from which planets might form. Vega, together with Deneb and Altair form the Summer Triangle.

CONSTELLATION• group of stars that, when seen from Earth, form

a pattern. The stars in the sky are divided into 88 constellations.

ZODIAC CONSTELLATION

http://www.enchantedlearning.com/subjects/astronomy/stars/constellations.shtmlhttps://image.shutterstock.com/z/stock-vector-zodiac-with-constellations-and-zodiac-signs-95268319.jpg

ARIES Mar. 21 - April 19

Located in the northern hemisphere. Its name means “the ram” in Latin.

Autumn constellation, and can be best viewed in the night sky during the month of November.

Aries is the 39th largest constellation in the sky, occupying 441 square degrees.

http://www.constellation-guide.com/constellation-list/aries-constellation/

TAURUS April 20 - May 20• Taurus constellation lies in the

northern sky. Its name means “bull” in Latin.

• In Greek mythology, the constellation is associated with Zeus.

• Autumn constellation, and can  be best viewed in the night sky during the month of December.

• Taurus is the 17th largest constellation in the sky, occupying an area of 797 square degrees.

http://www.space.com/17101-taurus-constellation.html http://www.constellation-guide.com/constellation-list/taurus-constellation/

GEMINI May 21 - June 21

• Gemini constellation is located in the northern hemisphere of the sky. Its name means “the twins” in Latin.

• Gemini is the 30th largest constellation in the sky, occupying an area of 514 square degrees.

• Winter constellation, and can be best viewed in the night sky during the month of January.

http://www.constellation-guide.com/constellat ion-list/gemini-constellation/

CANCER June 22 - July 22

• Cancer constellation is located in the northern sky. Its name means “the crab” in Latin.

• Cancer is the faintest of the 12 zodiac constellations

• Cancer is the 31st largest constellation in the sky, occupying an area of 506 square degrees.

•  Winter Constellation, and can be best viewed in the night sky during the month of February.

http://www.constellation-guide.com/constellation-list/cancer-constellation/

LEO July 23 - Aug. 22

• Leo constellation lies in the northern sky. It is one of the zodiac constellations and one of the largest constellations in the sky.

• Leo represents the lion and is usually associated with the Nemean lion in Greek mythology. 

• Leo is the 12th largest constellation in size, occupying an area of 947 square degrees.

•  Winter constellation, and can be best viewed in the night during the month of March. http://www.constellation-guide.com/constel

lation-list/leo-constellation/

VIRGO Aug. 23 - Sept. 22

• Virgo constellation lies in the southern sky. Its name means “virgin” in Latin.

• It contains Spica, one of the brightest stars in the night sky.

• Virgo is the second largest constellation in the sky, occupying an area of 1294 square degrees.

•  Spring constellation, and can be best viewed during the month of April.

http://www.constellation-guide.com/constellation-list/virgo-constellation/

LIBRA Sept. 23 - Oct. 23

• Libra constellation lies in the southern sky.

• The constellation’s name means “the weighing scales” in Latin.

•  Libra is the only zodiac constellation that represents an object, not an animal.

• Libra is the 29th constellation in size, occupying an area of 538 square degrees.

•  Spring constellation, and can be best viewed in the night sky during the month of May.http://www.constellation-gui

de.com/constellation-list/libra-constellation/

SCORPIUS Oct. 24 - Nov. 21

• Scorpius constellation lies in the southern sky.• Scorpius pre-dates the Greeks, and is one of the oldest

constellations known.• Scorpius is the 33rd constellation in size, occupying an

area of 497 square degrees.• Spring constellation, and can be best viewed in the night

sky during the month of June.

http://www.constellation-guide.com/constellation-list/scorpius-constellation/

SAGITTARIUS Nov. 22 - Dec. 21• Sagittarius constellation lies in the southern

sky.• It represents the archer.• Sagittarius is usually depicted as a centaur

holding a bow and arrow. • Sagittarius is one of the largest 

southern constellations.• It is easy to find because it lies on the Milky

Way and its brightest stars form an asterism known as the Teapot.

• Sagittarius is the 15th largest constellation in the sky. It occupies an area of 867 square degrees.

•  Summer constellation, and can be best viewed in the night sky during the month July. http://www.constellation-gui

de.com/constellation-list/sagittarius-constellation/

CAPRICORNUS Dec. 22 - Jan. 19

• Capricornus constellation is located in the southern sky.

• Its name means “the goat” in Latin.

• It is one of the faintest constellations in the sky.

• Capricornus is the 40th biggest constellation in the sky, occupying an area of 414 square degrees.

Summer constellation with an astronomical name of Capricornus, and can be best viewed in the night sky during the month of August.

http://www.constellation-guide.com/constellation-list/capricornus-constellation/

AQUARIUS Jan. 20 - Feb. 18• Aquarius lies in the region of the sky

which is sometimes referred to as the Sea.

• The constellation’s name means “the water-bearer” (or “cup-bearer”) in Latin.

• Aquarius is the 10th largest constellation in the sky, occupying an area of 980 square degrees.

• Summer constellation, and can be best viewed in the night sky during the month of September.

http://www.constellation-guide.com/constellation-list/aquarius-constellation/

PISCES Feb. 19 - Mar. 20

• Pisces constellation lies in the northern sky.

• Its name means “the fish” (plural) in Latin.

• Pisces lies between Aries constellation to the east and Aquarius to the west.

• Pisces is the 14th constellation in size, occupying an area of 889 square degrees.

•  Autumn constellation, and can be best viewed in the night sky during the month of October.

http://www.constellation-guide.com/constellation-list/pisces-constellation/

References: http

://www.nationalgeographic.com/science/space/universe/stars/ http://www.enchantedlearning.com/subjects/astronomy/stars/ http://www.enchantedlearning.com/subjects/astronomy/stars/life

cycle/

http://www.enchantedlearning.com/subjects/astronomy/stars/startypes.shtml

http://www.enchantedlearning.com/subjects/astronomy/stars/bright.shtml

http://www.enchantedlearning.com/subjects/astronomy/stars/majorstars.shtml