Characteristics of Stars by Faith Nordvik

Characteristics of Stars

faith_nor — 2014-05-06 20:29:34 UTC

2014-05-06 20:30:16 UTC

Characteristics used to classify stars

include color, temperature, size,

composition, and brightness.

Hertzsprung - Russell Diagram

faith_nor — 2014-05-06 20:30:24 UTC

Measuring Stars

2014-05-06 20:31:23 UTC

Brightness of stars

2014-05-06 20:31:39 UTC

Color and Temperature

2014-05-06 20:33:25 UTC

A star's color reveals its surface

temperature.

Red stars are the coolest= 3,200 degrees C.

Yellow stars are medium= 5,500 degrees C.

Blue stars are the hottest= 20,000 degrees C.

Size

2014-05-07 19:15:55 UTC

Most stars, such as the sun, are medium-sized stars.

Very large stars, also known as supergiant stars, if located where the sun is, would fill up the whole solar system as far out as Jupiter.

Most stars are much smaller than the sun, they are called dwarf stars. Dwarf stars are typically about the size of the Earth.

Neutron stars are even smaller than dwarf stars, reaching to about 20 kilometers in diameter.

faith_nor — 2014-05-07 19:17:28 UTC

Astronomers use parallax to measure

distances from nearby stars . Parallax is

a way to view an object from a different

perspective.

Variables

faith_nor — 2014-05-07 19:18:34 UTC

The brightness of the star depends on the size and temperature, so even if the star is huge it may not burn the brightest or is the star is smaller it my burn brighter then any other.

Absolute Brightness

2014-05-07 19:22:32 UTC

Absolute brightness or luminosity is the brightness of the star from standard distance. To find a stars absolute brightness an astronomer must find the apparent brightness and distance from the earth. The absolute brightness can vary greatly and the brightest of stars are brighter than even the dimmest of the stars.

Chemical Composition

2014-05-07 19:23:15 UTC

The chemical composition of most stars is about 73 percent hydrogen, 25 percent helium, and 2 percent other elements by mass. Spectrographs, a device that breaks light into colors and produces an image of the resulting spectrum, are used by astronomers to determine the elements found in stars.

faith_nor — 2014-05-07 19:24:42 UTC

faith_nor — 2014-05-07 19:26:03 UTC

The Hertzsprung - Russell (H - R) diagram is a graph relating surface temperatures and absolute brightness of stars.

faith_nor — 2014-05-07 19:31:16 UTC

On the x axis, the graph shows the surface temperature (°C). On the y axis, it shows the absolute brightness.

Apparent Brightness

2014-05-07 19:33:04 UTC

Apparent brightness is is the brightness of the star seen from Earth. Astronomers can measure apparent brightness very easily using electronic devices, but astronomers are not able to tell how much light the star is giving off, this is because the closer the star is to Earth the brighter it is, that's why the Sun is so bright and that it hurts to look at it because it is the closest star to the Earth.

faith_nor — 2014-05-07 19:34:22 UTC

Most of the stars form a diagonal group called the main sequence. More than 90% of stars (including the sun) are in the main sequence. At the bottom, are the white dwarfs. To the right of the main sequence is the giants and above those are the supergiants.

Constellation

2014-05-07 19:40:12 UTC

Astronomers use constellations to measure objects in space. Constellations are a pattern of a group of stars . Greeks thought of these stars as mythological objects or figures. We are in the milky way constellation. Also known as Sagittarius . There is 300 billion stars in the milky way.

faith_nor — 2014-05-07 19:40:46 UTC

Giants and supergiants are very bright.

White dwarfs can be hot, but usually not very bright.

The main sequence stars can vary in both brightness and temperature.

The supergiants are very bright, and can vary temperature.

Constellations

2014-05-07 19:41:35 UTC

Astronomers use the patterns in the night sky to locate objects in the night sky. Even though the stars in a constellation look close together, they are actually not. Different cultures gave different names to the constellations. A large constellation in the winter sky, Orion, is seen with a sword in his belt and an upraised arm.

Absolute Brightness Scale

2014-05-08 20:01:35 UTC

Apparent Brightness Equation

2014-05-08 20:07:32 UTC

Why Do Stars Twinkle Video:

2014-05-08 20:12:41 UTC

Night Sky Star Comparison

2014-05-08 20:14:50 UTC

faith_nor — 2014-05-08 20:18:17 UTC

Classifying Stars

2014-05-08 20:18:56 UTC

Size Doesn't Matter

2014-05-08 20:25:36 UTC

faith_nor — 2014-05-08 20:34:00 UTC

A number of different luminosity classes are distinguished:

0: hypergiants or extremely luminous supergiants

Ia: luminous supergiants

Iab: intermediate luminous supergiants

Ib: less luminous supergiants

II: bright giants

III: normal giants

IV: subgiants

V: main-sequence stars

VI: subdwarfs

VII: white dwarfs

2016-11-29 08:58:23 UTC

2016-12-12 12:20:03 UTC

2017-01-03 09:08:41 UTC

2017-01-07 23:46:06 UTC

2017-01-11 03:44:16 UTC

2017-01-13 23:59:21 UTC

2017-01-16 10:21:45 UTC

2017-01-16 10:51:39 UTC

2017-01-16 10:51:43 UTC

Ñ

2017-01-19 09:38:46 UTC

Name of stars

2017-01-23 11:29:29 UTC

2017-02-09 05:56:09 UTC

2017-02-09 05:59:03 UTC

2017-02-09 06:07:48 UTC

2017-03-28 04:07:28 UTC