However, the brightness of a star depends on
its composition and how far it is from the planet
. Astronomers define star brightness in terms of apparent magnitude
What 2 things would the apparent brightness of a star depend on?
Apparent brightness is the rate at which a star’s radiated energy reaches an observer on Earth. Apparent brightness depends on
both luminosity and distance
.
What causes stars to be different levels of luminosity?
Luminosity is also related to a star’s size. The larger a star is, the more energy it puts out and the more luminous it is. … Likewise,
if two stars are the same temperature but different sizes
, then the large star will be more luminous than the small one.
Which color star is hottest?
White stars are hotter than red and yellow.
Blue stars
are the hottest stars of all.
What could affect how a star appears in the night sky?
Stars do not really twinkle, they just appear to twinkle when seen from the surface of Earth. The stars twinkle in the night sky because of
the effects of our atmosphere
. When starlight enters our atmosphere it is affected by winds in the atmosphere and by areas with different temperatures and densities.
Why do stars twinkle on clear nights?
They twinkle as a
result of the atmospheric refraction of their light
. When the light of stars enters the earth’s atmosphere, it refracts many times and in random directions because of the varying optical densities of the different air layers of the atmosphere.
Why do star have colors?
The color of
a star is linked to its surface temperature
. The hotter the star, the shorter the wavelength of light it will emit. The hottest ones are blue or blue-white, which are shorter wavelengths of light. Cooler ones are red or red-brown, which are longer wavelengths.
What is star life cycle?
A star’s life cycle is
determined by its mass
. The larger its mass, the shorter its life cycle. A star’s mass is determined by the amount of matter that is available in its nebula, the giant cloud of gas and dust from which it was born.
How would you define apparent brightness?
The apparent brightness is
how much energy is coming from the star per square meter per second
, as measured on Earth. … The apparent brightness of a star is described by a magnitude that is a positive number for most stars, but can be a negative number for, say, Venus.
What star has the highest luminosity?
| Name Constellation Bolometric luminosity (Solar lum.) | Sun 1 | Alpha Centauri A Centaurus 1.519 | Sirius Canis Major 25.4 | Vega Lyra 40.12 |
|---|
Why is measuring the luminosity of stars difficult?
Why is measuring the luminosity of stars difficult?
The distance of stars relative to earth makes it difficult to measure brightness since
a bright star that is more distant might appear to be as bright as a more dim star closer to earth. … The class of star that corresponds to the color we observe from earth.
What are 2 factors that affect how bright a star appears in the night sky?
- Two Main Factors. There are actually two factors that influence how bright a star appears to our eyes:
- 1) The Star’s Actual Brightness. …
- 2) The Star’s Distance from Us.
What is the color of the brightest star?
Blue stars
tend to be the brightest, and red stars the dimmest. But more experienced observers will encounter red stars at night that are brighter than white or blue ones.
What is the biggest star?
The cosmos is full of objects that defy expectations. Although it’s difficult to pin down the exact traits of any given star, based on what we know, the largest star is
UY Scuti
, which is some 1,700 times as wide as the Sun.
What color is the hottest star on the HR diagram?
Stars on the Main Sequence that are hotter than the Sun are also larger than the Sun. So
hot blue stars
are more luminous (and therefore appear higher in this diagram) for two reasons: they are hotter, and hot objects are more luminous than cool objects, but they are also larger.
Why do stars twinkle red and blue?
This is because
of scintillation (“Twinkling”) as the light passes through the atmosphere of the Earth
. As the air moves in and out, the starlight is refracted, often different colors in different directions. Because of this “chromatic abberation,” stars can appear to change colors when they are twinkling strongly.
