3rd chapter: stars

• the only star in the solar system

• has own source of energy, radiated in all directions throughout the solar system

• massive sphere of gases that emit their own light and provide hear (star)

Sun

age of the sun

4.5 billion yrs old

milky way contains more than ______ billion, including our sun

100 billion

The universe could contain up to __________ stars

1 septillion

Stars near the sun

• alpha centauri A

• proxima centauri (the closest)

• alpha centauri B

sun/stars are mainly composed of?

91% H (hydrogen) and 8.9% He (helium)

stars emit their own light through process called

Nuclear Fusion

combination of the atomic nuclei from the same element to form another element

nuclear fusion

what size (star) is the sun?

a medium sized star

there are stars with much more mass and are larger than the sun like Betelgeuse

standard unit of mass in astronomy

Solar Mass

• Sun = 1 solar mass

• Red Dwarf = 0.08 solar mass

• Red Giant = < 5 solar masses

• Rigel = 3.5 solar masses

the more massive a star is, the greater the gravity,

the hotter and denser a star must be

approximate mass of the sun

1.98892 × 10 ^ 30 kg

the heaviest star is known as

R136a1 (300 times the suns mass)

What color of the star shines with the hottest temp and coolest temp

Blue stars = hotter

Red stars = cooler

because of of wavelength and frequency

R M I V U X G (order of emag spectrum)

uses the letters O, B, A, F, G, K, and M to designate a star's spectral type, by subdividing the range of possible stellar temperatures, from the coolest, M, to the hottest, O

Morgan - Keenan System

Oh Be A Fine Guy, Kiss Me

surface temp of the sun and its color

Sun is

• yellow

• surface temp of 5,000 K

  astronomers place stars in spectral colors class categories based on their surface temp

the energy output from the surface of a star per second measured in _____

the brightness of a star depends upon the ______ and its ______

watts

distance and luminosity

ways of observing the brightness of the sun

Absolute Magnitude

• true brightness of a star

• in comparison to sun

Apparent Magnitude

• how bright a star appears to be on earth

Rigel is _______ times larger than our sun

Sun and Rigel is approximately _____ light yrs away from each other

60,000

900 light yrs away (the distance light travels in one earth year)

why do stars twinkle?

• also called STELLAR SCINTILLATION

• light of the star is bent (refracted) many times in diff. directions (layers of the atmosphere)

diagram that describes the relationship between the absolute magnitude, color and temp of stars

Hertzsprung-Russel Diagram

designates the color of the stars

• depends on temp

• from hot to coolest

Spectral Class (morgan keenan system)

Life Cycle of a Star

Nebula (dust + gas)

Protostar

Main Sequence Star

• Super Red Giant

  • Supernova

    • Neutron Star

    • Blackhole (massive)

• Red Giant

  • White Dwarf

  • Black Dwarf

refers to a group of stars that forms a particular pattern in the sky

Constellations

a distinctive pattern formed by a group of stars which belongs to one or more constellation

Asterism

Big Dipper (Big Bear) is an asterism of the constellation ursa major

IAU

International Astronomical Union

How many recognized constellations are there

88

why are stars are not related to one another

because they have different distances (light years)

in the course of the night, constellations shange positions (east to west) in the night sky

rotation of the earth on its axis

causes diff. constellations to be observed at diff times of the year

revolution of earth around the sun

Types of constellations

Circumpolar Constellations

Non-Circumpolar Constellations

Zodiacal Constellations

• never fully set below the horizon

• can be seen all year long near NORTH CELESTIAL POLE (NCP)

• caused by earths rotation

• moves counterclockwise around polaris

• usually seen in the northern hemisphere, where PH is located

Circumpolar Constellations

Major Circumpolar Constellation

Ursa Major - big dipper is an asterism of ursa major

Ursa Minor - tail represents polaris

Cassiopeia - Queen of ethiopia, W or M, forms a crown, northern sky (seen)

Draco - dragon named ladon, guards golden apple tree of Goddess Hera

Cepheus - King of ethiopia, kingdom (mukang house)

• constellations appear in the sky only in a particular season

• also known as SEASONAL CONSTELLATIONS

Non-circumpolar Constellations

WINTER CONSTELLATIONS (DEC - FEB)

winter in northern hemisphere and summer in southern hemisphere

• ORION

• Cancer

• Gemini

• Monaceros

• Taurus

• and friends

SPRING CONSTELLATIONS (MAR - MAY)

spring in northern hemisphere, autumn in southern hemisphere

• LEO (yeahhhhhhh)

• Bootes (hahahah)

• Leo Minor

• Ursa Major

• Virgo

• and friends

SUMMER CONSTELLATIONS (JUNE - AUG)

summer in northern, winter in southern

• LYRA

• Hercules (ngik)

• Corona Borealis

• Ophiuchus

• Sagittarius

• Delphinus (YEZZZZZ)

• and friends

AUTUMN CONSTELLATIONS (Sept to Nov)

visible during clear atumn nights, if u point at it u see andromeda galaxy

spring in southern

• ANDROMEDA

• Pegasus (bida bida)

• Pisces

• Aries

• Triangulum (bat kaya no)

• Cassiopeia

• and friends

Handy way to measure distance

pinky - 1 deg

girl scout fingers - 5 deg

fist - 10 deg

rockstar na walang thumb - 15 deg

rockstar na walang pointer - 25 deg

• constellations that lie along the plane of the ecliptic

• the ecliptic (apparent path) of the sun is the circular path of the sun across the sky as seen from earth

• ecliptic passes through 13 constellations - astronomy

• 12 only - astrology

Zodiacal Constellations

circular path of the sun across the sky as seen from the earth

apparent path

Ecliptic

the zodiacal that is april 19-may 13

ARIES

Zodiacal may 14 - june 19

TAURUS

zodiacal june 20 - july 20

gemini

july 21 - aug 9

cancer (hala!)

aug 10 - sept 15

LEO YESSSSS

sept 16 - oct 30

virgo

oct 31 - nov 22

libra

nov 23 - nov 29

scorpius

nov 30 - dec 17

OPHIUCHUS YESSS

dec 18 - jan 18

sagittarius

jan 19 - feb 15

capricornus

feb 16 - mar 11

aquarius

march 12 - april 18

pisces

SUNOD SUNOD NA ZODIACAL CONSTE

ARIES - april 19 - may 13

TAURUS - may 14 - june 19

GEMINI - june 20 - july 20

CANCER - july 21 - aug 9

LEO - aug 10 - sept 15

VIRGO - sept 16 - oct 30

LIBRA - oct 31 - nov 22

SCORPIUS - nov 23 - nov 29

OPHIUCHUS - nov 30 - dec 17

SAGITTARIUS dec 18 - jan 18

CAPRICORNUS - jan 19 - feb 15

AQUARIUS - feb 16 - mar 11

PISCES - march 12 - april 18

Uses of constellation

• find location

• farming

• navigation (sea)