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Sunspot: A spot on the sun of darker colour because it's a cooler area.
VY Canis Majoris, a red hypergiant star, is the largest star known, between 1800 and 2100 solar diameters in width. Like main sequence stars, hypergiants come in all spectral flavors: there are blue hypergiants, red hypergiants, and yellow hypergiants.
NEUTRON STARS
A neutron star is a type of stellar remnant that can result from the gravitational collapse of a massive star and after a supernova. Neutron stars are the densest and smallest stars known to exist in the universe. Their radius of only about 12–13 km, they can have a mass of about two Suns! Neutron stars are created when giant stars explode in supernovas and their cores collapse, with the protons and electrons fusing to form neutrons. They are so dense that a single teaspoon would weigh a billion tons. Gravity on a neutron star is about 2 billion times stronger than gravity on Earth! Power from the supernova that created the star gives it an extremely quick rotation, this causes it to spin several times in a second. Neutron stars can spin as fast as 43,000 times per minute, gradually slowing down over time.
Calvera
Astronomers using NASA's Swift X-ray telescope detected a neutron star within 250 to 1,000 light-years of Earth, making it the closest neutron star ever known. The object, located in the constellation Ursa Minor, it was then named Calvera.
Calvera
Neutron star being created
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Bellatrix, also called The Amazon Star, is a blue giant star in the constellation Orion. At 252 light years away, it is the 27th brightest star in the Earth's sky. Bellatrix is about 8.4 times the Sun's mass. It has an estimated age of approximately 20 million years It's temperature is at 21727 degrees Celsius, and 244.6 light years away from Earth.
BLUE
GIANTS
Blue Giant stars are very large and dense, this causes them to burn their fuel quickly which means that their temperatures are very hot at 19727 degrees Celsius. These stars often run out of fuel within 10,000 -100,000 years.
A blue giant is extremely bright. Even though blue giant stars are rare, they make up many of the stars we see at night because they shine so brightly. Blue giant stars die in a spectacular way. They grow larger just like the sun-sized stars, but then instead of shrinking and forming a planetary nebula, they explode in what is called a supernova. Supernova explosions can be brighter than an entire galaxy, and can be seen from very far away.
This shows a red giant's core and shell, you can see that it is possible for the core to fuse Carbon and Oxygen.
Hypernova
HYPERGIANTS
These stars are really, (stupid) big... (stupid) ENORMOUS! They were first identified separately from other supergiant stars because of their significantly large luminosity and mass as compared to similar stars. Because of their high mass and luminosity, hypergiants only live a few million years; quite short compared to the billions of years that stars like our Sun will exist. Eventually the core will fuse heavier and heavier elements until an iron core is formed. The resulting core collapse causes a supernova explosion of incredible magnitude. Some say that instead of a typical type II supernova either a Gamma-ray Burst (GRB), when a Hypergiant goes nova, sometimes it's called a hypernova! Hypergiant stars have a diameter between about 100 and 2100 times that of the Sun.
The Stars can be defined using the 5 basic characteristics
Hypernova
RED
After the White Dwarf condenses and it's outer layers expand outward, at this stage the star becomes a Red Giant. A red giant is so large that its heat spreads out and the surface temperatures are cooler, but its core remains hot. Red giants exist for a shorter time, about a billion years. These massive stars are hot enough to turn the helium in the core (which was made by fusing two hydrogen), into heavy elements like carbon, or even oxygen. Reg giants are about 100 times bigger than it's original star. It's temperature at 6227 degrees Celsius.
- Brightness
- Color
- Surface temperature
- Size
- Mass
The Old and the Large
Stars ball of hot gases
- The heat of the star is made in the center by nuclear fusion reactions
-There are lots of different colors and sizes of star
One Example of a Red Giant ...
MIRA
Mira is a red giant star estimated 200–400 light years away in the constellation Cetus. Mira is a binary star (this means two stars in which one star revolves around the other or both revolve around a common center) system that consists of a red giant (Mira A) undergoing mass loss and a high temperature white dwarf companion (Mira B).
Ultraviolet mosaic of Mira's bow shock and tail
Brightness
How does the star differ from planet ?
The brightness of a star as viewed from Earth is dependent on many factors such as color intensity and distance.
Apparent Brightness – is the brightness of a star as it appears from Earth.
The apparent brightness decreases as its distance from you increases
Absolute Brightness – is how bright a star really is. The absolute brightness is a characteristic of the star and is not dependent on its distance from Earth.
- Stars undergoes nuclear reaction that burns hydrogen core, planets do not.
- - Stars are massive compared to the majority of the planets.
- - Stars formed when a gas of cloud in the nebula while planets are created when disk of preexisting star begins to condense around the core.
- - Stars twinkle in the sky while the planets do not.
- - Planets are always on the eliptic plane while the stars will be anywhere in the sky.
have a cooler surface temperature than any other of the types of stars with a temperature of under 3227 degrees Celcius
GIANTS
A small, cool, very faint, main sequence star
An example of a Red Dwarf star is the Proxima Centauri. The Proxima Centauri is a red dwarf that belongs to the main sequence on the Hertzsprung–Russell diagram. This star is about 4.24 light-years from the Sun. It's star in the constellation of Centaurus and was discovered in 1915 by a Scottish astronomer named Robert Innes. This is the nearest known star to the Sun, making it very special because our Sun has no companion stars. Too faint to be seen with the naked eye, Proxima Centauri is part of a three star system with Alpha Centauri A and B. Proxima Centauri's mass is about an eighth of the Sun's, and its average density is about 40 times the Sun.
This is a picture of Proxima Centauri
The diagram on the left shows the Sun's closest neighbours,
Proxima Centauri
Red dwarfs are the most common type of star
Color and Temperature
Red dwarf stars have a mass of between 7.5% and 40% of the Sun
Yellow dwarfs are stars of medium size
A yellow dwarf is a star that belongs to the main sequence
Our star; the sun, is a yellow dwarf star
Approximately 10% of the stars in the Milky Way are yellow dwarfs
YELLOW DWARFS
As it cools, it will grow dimmer, and will eventually become a black dwarf
The surface temperature of about 4727-5727 degrees Celsius
Picture of the sun
THE SUN
One example of a yellow dwarf star is our Sun. Our Sun's temperature is at 5505 degrees Celsius. The Sun is 864,400 miles (1,391,000 kilometers) across, and this is about 109 times the diameter of Earth. The Sun weighs about 333,000 times as much as Earth. It is so (stupid) big that about 1,300,000 planet Earths can fit inside of this star. In fact, Earth is about the size of an average sunspot!
WHITE DWARFS
White dwarfs are stars that have burned up all of the hydrogen they once used as nuclear fuel. Fusion in a star's core produces heat and outward pressure.
When dwarfs reach the end of their long evolutions, smaller stars, those that are up to eight times as massive as our own sun, typically become white dwarfs.
As we had learned in one of the videos we viewed in class, white dwarfs are incredibly dense. A teaspoonful of their matter would weigh as much on Earth as an elephant (5.5 tons).
When the hydrogen used as fuel is used up, and fusion slows, gravity causes the star to collapse in on itself.
As the star condenses, it heats up even more, burning the last of its hydrogen and causing the star's outer layers to expand outward.
STARS
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.
Parallax - is the apparent shift in the position of an object when viewed from two different positions.
A super giant star is the exact same thing as a giant star only MUCH bigger. Supergiants are among the most massive and most luminous stars. They are at the top region of the Hertzsprung–Russell diagram. Supergiants have masses from 8 to 12 times the Sun, and luminosities from about 10,000 to over a million times the Sun.
SUPERGIANTS
blue giants
Herzsprung -Russell diagram
RIGEL
Orion The Hunter
Rigel, an example of a blue giant is in the constellation Orion the Hunter. This constellation is one of the easy to spot and Rigel is one of the brightest stars in the night sky. Rigel is actually a three star system consisting of the blue supergiant Rigel A and two much dimmer companions. This star is 40,000 times brighter than the sun and is about 800 light years from Earth. Over the next few million years Rigel will expand to an even greater size as it becomes a red supergiant and may eventually explode as a supernova. If Rigel does explode as a supernova it will become the brightest object in the night sky apart from the moon.
Stars come in all different sizes, temperatures, colors, types, and have different deaths
So next time you look up into the sky, and see stars, think about they might really look like if you were much, much closer to them
STARS
Hope you got a better understanding of these magnificent objects we call
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"Rigel in Orion Is Blue-white | EarthSky.org." EarthSky. Web. 5 Mar. 2015. <http://earthsky.org/brightest-stars/blue-white-rigel-is-orions-brightest-star>.
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Bibliography
Variable stars are stars that appear to vary in brightness over time. There are many different underlying causes of variability. For many types of these stars, the variation in brightness regularly repeats and the periods range from a couple of hours to hundreds of days. Over 150,000 variable stars are known, and many thousands more are suspected to be variable stars. One important group of variable stars is pulsating variable stars. These stars are known as intrinsic variables since they actually pulsate. The expand and shrink, kinda like they're breathing.
Variable Stars