2. • Are the stars same in size?
• Are the stars same in color?
• Are the stars equally bright?
• What makes up a star?
• Can you really tell the size of
the star by just looking at it?
3. • is a luminous ball of gas, mostly hydrogen
and helium, held together by its own
gravity
• The nearest star to Earth is the Sun, which
is the source of most of the planet's
energy.
• giant nuclear reactors
4. • In the center of stars, atoms are taken
apart by tremendous atomic collisions that
alter the atomic structure and release an
enormous amount of energy.
• This makes stars hot and bright.
• Stars are powered by nuclear fusion in
their cores, mostly
converting hydrogen into helium.
5. • The nuclear reactions
inside convert hydrogen
into helium by means of a
process known as fusion.
It is this nuclear reaction
that gives a star its energy.
Fusion takes place when
the nuclei of hydrogen
atoms with one proton
each fuse together to form
helium atoms with two
protons
6. • Stars form inside relatively dense
concentrations of interstellar gas and
dust known as molecular clouds. These
regions are extremely cold
(temperature about 10 to 20K, just
above absolute zero). At these
temperatures, gases become
molecular meaning that atoms bind
together
7. • Each star has its own spectrum.
• Most stars have a chemical makeup that is
similar to the sun, with hydrogen and
helium together making up to 96 to 99.9
% of a star’s mass.
8.
9. • The Sun is an average star:
• it’s not hot or cool
• it’s not large or small.
• We can compare stars by temperature,
size, & brightness.
11. • Cooler stars (3,200oC) appear reddish
• Medium stars (5,500oC) appear yellow
• Hottest stars (over 20,000oC) are blue
oC
oC
oC
oC
oC
Alnilam Epsilon Iridani
Proxima Centuari
sun
12. • It is a common
misconception that
the Sun is yellow, or
orange or even red.
However, the Sun is
essentially all colors
mixed together,
which appear to our
eyes as white. This is
easy to see in pictures
taken from space.
13. • Image courtesy NASA It is a
common misconception that the
Sun is yellow, or orange or even
red. However, the Sun is
essentially all colors mixed
together, which appear to our
eyes as white. This is easy to see
in pictures taken from space.
• Rainbows are light from the Sun,
separated into its colors. Each
color in the rainbow (red,
orange, yellow, green, blue,
violet) has a different
wavelength. Red is the longest,
blue the shortest.
14. • When we see the Sun at sunrise or sunset,
when it is low in the sky, it may appear
yellow, orange, or red. But that is only
because its short-wavelength colors (green,
blue, violet) are scattered out by the Earth's
atmosphere, much like small waves are
dispersed by big rocks along the shore.
• Hence only the reds, yellows, and oranges
get through the thick atmosphere to our
eyes.
15. • When the Sun is high in the sky, the
shorter waves, primarily the blue, strike air
molecues in the upper atmosphere and
bounce around and scatter. Hence
explaining why the sky looks blue.
16. • SIZE/DISTANCE/ TEMPERATURE
• Actual brightness ( absolute)
–the brightness the star would have
if all stars were the same standard
distance from Earth
Apparent brightness.
• brightness depends on how far away
a star is from the Earth.
17. • Stars are separated by vast distances.
• Astronomers use units called light years
to measure the distance of stars
• A light-year is the distance that light
travels in a vacuum in a year
• Proxima Centauri, is the closest star to
the sun.
18. • The change in position of an object with
respect to a distant background.
• As Earth moves in its orbit, astronomers
are able to observe stars from two
different positions.
19. • A star's brightness is known as its
magnitude/ luminosity. Astronomers rate
the magnitude of a star with a scale that
gives brighter stars a low number and dim
stars a higher number.
• The brightest star the night sky is
• Sirius. With a magnitude of -1.46,
20. • Stars are identified by their color, which indicates
their temperature. They are divided into what are
known as spectral classes. These classes are O, B,
A, F, G, K, and M. Class O stars are the hottest
and are blue in color. The coolest stars are
identified as class M and are red in color.
21.
22.
23.
24. • Each star has its
own spectrum.
• Most stars have a
chemical makeup
that is similar to
the sun, with
hydrogen and
helium together
making up to 96 to
99.9 % of a star’s
mass.
25. • When we look at the night sky, we see
thousands of stars. In reality, there are
approximately 400 billion stars in our
galaxy, and there are about 170 billion
galaxies. A person can see only about
3,000 stars on the average.
26.
27. • A nebula is a large cloud of gas and dust
spread out over a large volume of space.
• Some nebulas are glowing clouds lit from
within by bright stars.
• A star is formed when a contacting cloud
of gas and dust becomes so dense and
hot that nuclear fusion begins.
28.
29.
30. • VY Canis Majoris
• Star Size Comparison:
• The biggest/largest known stars in the
Universe. VY Canis Majoris (VY CMa) is a
red hypergiant star located in the
constellation Canis Major
31.
32.
33. • Latin
• Con= with
• Stella= stars
–Picture made with stars
• Constellatio= set of stars
34. • group of stars that, when seen from Earth,
form a pattern.
• 88 constellations
• IAU
• Humans, animals
and mythological
creatures
Babylonians and Greek
civilizations
Mesopotania 4000BC
35.
36.
37.
38.
39. • 14 men and women,
9 birds,
• 2 insects,
19 land animals,
• 10 water creatures,
2 centaurs,
• 1 head of a hair
1 serpent
• 1 dragon,
1 flying horse,
• 1river, and
29 non-living
objects.
40.
41.
42. Constellation
• Region in the sky
which naturally
contain stars
• Ursa Major
Asterism
• Smaller pattern
that make up the
bigger
constellation
• Big dipper
• The Belt of Orion
• The Kite
• The Teapot
asterisms are smaller patterns that make up the bigger constellations.
43. • A star pattern that is NOT
officially recognized by
the international scientific
community (International
Astronomical Union) as a
constellation
• The stars that form
asterisms can be part of
one or more
constellations. For
example, the Big Dipper is
an asterism within the
Ursa Major constellation.
47. • Filipinos call this pattern
• “Balatik” -trap used in hunting
• wild pigs
• Christian Filipinos named
• the three stars
• (Orion’s belt)
• Tatlong Maria or
• Tres Marias
•
52. • Aquarius, the water
bearer
Aries, the ram
Cancer, the crab
Capricorn, the goat
Gemini, the twins
Leo, the lion
Libra, the scales
Pisces, the fish
Sagittarius, the archer
Scorpius, the scorpion
Taurus, the bull
Virgo, the virgin
53. • Andromeda, the princess
Antlia, the pump
Aquila, the eagle
Auriga, the chariot driver
Bootes, the herdsman
Caelum, the chisel
Camelopardalis, the giraffe
Canes Venatici, the hunting
dogs
Canis Major, the big dog
Canis Minor, the little dog
Cassiopeia, the queen
Cepheus, the king
Cetus, the whale
Columba, the dove
Coma Berenices, Berenice's
hair
Corona Australis, the
southern crown
Corona Borealis, the northern
crown
Corvus, the crow
Crater, the cup
Cygnus, the swan
Delphinus, the dolphin
Draco, the dragon
Equuleus, the little horse
Fornax, the furnace
Hercules, the hero
Horologium, the clock
Hydra, the water snake
Lacerta, the lizard
Leo Minor, the little lion
Lupus, the wolf
Lynx, the lynx
Lyra, the harp
Microscopium, the
microscope
Monoceros, the unicorn
Ophiuchus, the sepent holder
Orion, the hunter
Pegasus, the flying horse
Perseus, the Medusa killer
Pisces Austrinus, the
southern fish
Puppis, the ship's stern
Pyxis, the ship's compass
Sagitta, the arrow
Sculptor, the sculptor
Scutum, the shield
Serpens, the snake
Sextans, the sextant
Telescopium, the telescope
Triangulum, the triangle
Ursa Major, the big bear
Ursa Minor, the little bear
Vulpecula, the little fox
54. • the officially recognized authority
in astronomy for assigning designations to
celestial bodies such as stars, planets,
and minor planets, including any surface
features on them
55. • Apus, the bird of paradise
Ara, the altar
Carina, the ship's keel
Centauras, the centaur
Chamaeleon, the
chameleon
Circinus, the compass
Crux, the southern cross
Dorado, the swordfish
Eridanus, the river
Grus, the crane
Hydrus, the water snake
Indus, the Indian
Lepus, the rabbit
Mensa, the table
Musca, the fly
Norma, the surveyor's level
Octans, the octant
Pavo, the peacock
Phoenix, the phoenix
Pictor, the easel
Reticulum, the net
Triangulum Australe, the
southern triangle
Tucana, the toucan
Vela, the ship's sails
Volans, the flying fish
56.
57.
58. • commonly known as
North Star
• is the brightest star in
the constellation Ursa
Minor (Little Dipper)
• Because it lies nearly in a
direct line with the axis
of the Earth's rotation
"above" the North Pole
59. • In Metro Manila, when
you face North, Polaris,
which is 11.3o from the
horizon, is seen at
around 15° due to
atmospheric refraction.
In some parts of the
country (i.e. Southern
Philippines),
• east to west
• the stars appear to be
moving because of the
rotation of the Earth on
its axis
60. • A star trail is a type of photograph that uses long-
exposure times to capture the apparent motion of
stars in the night sky due to Earth's rotation.
• A star-trail photograph shows individual stars as
streaks across the image, with longer exposures
resulting in longer arcs.
61.
62. • studies the universe beyond Earth,
including its formation and development,
and the evolution, physics, chemistry,
• meteorology, and motion of celestial
objects (such as galaxies, planets, etc.)
and phenomena that originate outside
the atmosphere of Earth
63. • Spain, in Canary
Islands which is
currently the
world's largest
single-aperture
64.
65. • Agriculture- in ancient times, there were no calendars
• Religion- Many cultures believed that the positions of
the stars were their God's way of telling stories
• Navigation- One can figure out his/her latitude
(North/South) just by looking at how high Polaris
appears- North Star
• Astronomical-By looking for groups of stars in a
• particular pattern, professional and amateur
• astronomers can locate specific stars within the
• group
Editor's Notes
In the center of stars, atoms are taken apart by tremendous atomic collisions that alter the atomic structure and release an enormous amount of energy.
This makes stars hot and bright
A star is like a gigantic nuclear furnace. The nuclear reactions inside convert hydrogen into helium by means of a process known as fusion
This forms a helium atom and an extra neutron. In the process, an incredible amount of energy is released. When the star's supply of hydrogen is used up, it begins to convert helium into oxygen and carbon.
The color of the star indicates its surface temperature.
When the Sun is high in the sky, the shorter waves, primarily the blue, strike air molecues in the upper atmosphere and bounce around and scatter. Hence explaining why the sky looks blue.
Luminosity = proper term for brightness
The main technique to measure the distance to a star is from its parallax
So, the procedure to measure the brightness is as follows: First, one determines the flux from the star (the rate at which energy reaches us from the star per unit area). This can be done using a CCD camera quite easily. Then, as one knows the distance to the star, one can determine how luminous the star should be to give the required flux.
it is almost 15 times brighter than a star with a magnitude of zero. Stars with a magnitude of 8 or more are too dim to see with the naked eye.
The compositions of stars are determined through spectroscopy.
Spectroscopy is the study of something using spectra. Recall from the Electromagnetic Radiation chapter that a spectrum is what results when you spread starlight out into its individual colors
Figure 2 shows the size of the Sun, the closest star to Earth, as compared to some other stars that we see at night. As we can see, the Sun is so small compared to other nearby stars. Also, Sirius, which appear bigger than Rigel, is actually very small compared to Rigel. It appears larger only because it is closer to us
Constellations were first found and w
The constellations are totally imaginary things that poets, farmers and astronomers have made up over the past 6,000 years (and probably even more!). The real purpose for the constellations is to help us tell which stars are which, nothing more as part of the historical record in Mesopotamian culture around 4000 B.C.
twenty two different constellation names start with the letter "C."
Crux which only takes up 0.17 percent of the sky.
Polaris stands almost motionless in the sky, and all the stars of the Northern sky appear to rotate around it
This function is precisely what makes them so useful to scientists and astronomers. Galileo is most commonly associated with the first telescopes though he is not the inventor. He was, however, the first person to use a telescope to view the night sky which is how he discovered the Milky Way. Several kinds telescopes exist and are used to observe different types of electromagnetic radiation
a space through which light passes in an optical or photographic instrument, especially the variable opening by which light enters a camera.
Agricuture-The ancient peoples knew for example that when the constellation Orion started to be fully visible winter was coming soon
Religion- People thought that the Gods lived in the heavens and that they created them.
Navigation- This allowed for ships to travel across the globe. It allowed for the discovery of America, the spread of European culture, and civilization as we know it today.
