Our five pointed star capiz shell Christmas tree topper is 9 inches tall and the star is about 8.5 inches in diameter. The five pointed star capiz shell Christmas tree topper has a gold wire frame with triangular shaped capiz shell panels. The wire frame in the center of the five pointed star capiz shell Christmas tree topper is shaped like a five pointed star with a star shaped piece of capiz shell in it. There are gold wire scroll designs decorating the five pointed star capiz shell Christmas tree topper with a white pearl at the tip of each scroll design. The five pointed star capiz shell Christmas tree topper has a gold metal coil base that attaches to your tree.
Color and Temperature of Stars.
If you look carefully at the stars, even without binoculars or a telescope, you will see a range of color from reddish to yellowish to bluish. For example, Betelgeuse looks reddish, Pollux is yellowish and Rigel looks bluish.
A star’s color depends on its surface temperature. Astronomers measure star temperatures in a metric unit known as the Kelvin. One Kelvin equals exactly 1 Celsius degree but the Kelvin and Celsius scales start at different points. The Kelvin scale starts a 273.15 Celsius. Therefore a temperature of 0 K equals 273.15 C, or 459.67 F. A temperature of 0 C equals 273.15 K.
Dark red stars have surface temperatures of about 2500 K. the surface temperature of a bright red star is approximately 3500 K, that of the sun and other yellow stars, roughly 5500 K. Blue stars range from about 10,000 to 50,000 K in surface temperature.
Although a star appears to the unaided eye to have a single color, it actually emits a broad spectrum of colors. You can see that starlight consists of many colors by using a prism to separate and spread the colors of the light of the sun, a yellow star. The visible spectrum includes all the colors of the rainbow. These colors range from red, produced by the photons or particles of light, with the least energy, to violet, produced by the most energetic photons.
visible light is one of six bands of electromagnetic radiation. Ranging from the least energetic to the most energetic, they are, radio waves, infrared rays, visible light, ultraviolet rays, X rays and gamma rays. All six bands are emitted by stars, but most individual stars do not emit all of them. The combined range of all six bands is known as the electromagnetic spectrum.
Astronomers study a star’s spectrum by separating it, spreading it out and displaying it. The display itself is also known as a spectrum. The scientists study thin gaps in the spectrum. When the spectrum is spread out from left to right, the gaps appear as vertical lines. The spectra of stars have dark absorption lines where radiation of specific energies is weak. In a few special cases in the visible spectrum, stars have bright emission lines where radiation of specific energies is especially strong.
An absorption line appears when a chemical element or compound absorbs radiation that has the amount of energy corresponding to the line. For example, the spectrum of the visible light coming from the sun has a group of absorption lines in the green part of the spectrum. Calcium in an outer layer of the sun absorbs light rays that would have produced the corresponding green colors.
Although all stars have absorption lines in the visible band of the electromagnetic spectrum, emission lines are more common in other parts of the spectrum. For instance, nitrogen in the sun’s atmosphere emits powerful radiation that produces emission lines in the ultraviolet part of the spectrum.
The Size of Stars.
Astronomers measure the size of stars in terms of the sun’s radius. Alpha Centauri A, has a radius of 1.05 radii, which is the plural of radius and is almost exactly the same size as the sun, Rigel is much larger at 78 solar radii and Antares has a huge size of 776 solar radii.
A star’s size and surface temperature determine its luminosity. Suppose two stars had the same temperature, but the first star had twice the radius of the second star. In this case, the first star would be four times as bright as the second star. Scientists say that luminosity is proportional to radius squared, that is multiplied by itself. Imagine that you wanted to compare the luminosities of two stars that had the same temperature but different radii. First, you would divide the radius of the larger star by the radius of the smaller star. Then, you would square you answer.
Now, suppose two stars had the same radius but the first star’s surface temperature, measured in Kelvins, was twice that of the second star. In this example, the luminosity of the first star would be 16 times that of the second star. Luminosity is proportional to temperature to the fourth power. Imagine that you wanted to compare the luminosities of stars that had the same radius but different temperature. First, you would divide the tempe