The Sun is only star which exit in our solar system and it is the nearest star. It is very big in size as compare to earth or any planet in our solar system. All planets revolve around it. Sun is the Centre of our solar system. Nearest planets form the sun is Mercury, then Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.
It gives energy to us so that life on earth
is sustainable. If sun do not give energy, then our earth is too cold. So, sun
is very necessarily things to us. But it has some problem. On the surface of
sun, many things occurs continuously so that our life is in danger but earth
magnetic field is enough to save us. So, let start know these things What are the parameters of sun & atmosphere of the
sun?
Solar Parameter
Solar Mass: Mass
of the sun is 2*(10^30)kg. Mass of the sun continuously decreases due to radiated radiation in
form of solar wind, solar flares, CME, and solar storm.
Solar Luminosity: The
total energy emitted by sun in the electromagnetic radiation in per time and
unit area. Solar luminosity is key factor to determine that sustainable life is
possible or not in any planet.
Solar Luminosity = 3.86*(10^26)watts.
Solar Radius: Radius of the sun is 6.7*(10^8)m. value of solar radius also changes. And mean solar distance from earth is 1.5*(10^11)m. And when we viewed from the earth, the angular diameter of sun is 32 minutes (32’).
Solar Temperature: The Sun has many layers of atmospheres and
also many layers inside the sun. so that temperature is different at surface,
it’s atmosphere and inside the sun.
Sun's Atmospheres
The Sun's atmosphere is a complicated and changing area that goes out into space for millions of kilometers. It has three different layers: the photosphere, the chromosphere, and the corona.
Photosphere: This is the visible part of sun. we can say that this surface mostly emits visible light. Its temperature is about from starting point 6000K to 4500k at top of photosphere it means its temperature decrease with height increase. and extended from 500km form the sun’s surface (above the sun’s interior) like earth has a solid structure then earth’s atmosphere starts. From Earth, the photosphere looks like a yellow disc, and it has a grainy structure because of how heat moves around inside the Sun.
The grains are made up of convection cells that move energy from inside the Sun to its surface.
This is the coolest layers on sun. the Density of the Photosphere is very thin as compare to the air that we breath.
In photosphere mostly hydrogen and 60 other chemical composition are present. This other chemical composition is also present on earth in ratio.
Chromosphere: this layer present above the photosphere and below the corona. It lies from approx. 500km to 2000km. and its temperature is increased 25000K in few kilometers. Its temperature is high as compare to photosphere. How its possible? Spicules are lies in the chromosphere. They are made of hot gas and travel in the form of jets from the upper surface of photosphere to extended in the chromosphere up to a height approx. 10000km and timing is approx. 15 minutes. These spicules ejected all over lower portion of chromosphere and they carry/transport mass and energy and this causes chromosphere has more temperature as compare to photosphere.
The prominences, which are big, bright rings of gas that reach out from the Sun's surface, are also in the chromosphere. The magnetic field of the Sun causes prominences, which can last for a few weeks.
Chromosphere’ density has decreases by factor approx. 10000 from the of photosphere and due to this low density, we can’t see this layer in normal times. When solar eclipse occurs then we see this layer.
Corona:
The corona is the highest layer of the Sun's atmosphere. It is the hottest layer, with temperatures between 1 and 3 million degrees Celsius. It extended from 2600km from sun’s surface and into space for millions of kilometers. and is mostly made up of ionized gases, mostly hydrogen and helium.
This layer is outermost layer of the sun, known as corona. It’s also can’t be seen by in normal times, when total solar eclipse occurs then we see it. Because density of corona is very low and they have very little light and as compare to the photosphere has very bright light. This is the cause of corona not visible in normal time.
Now one question arises when temperature of corona is high as compare to both, chromosphere and photosphere. And temperature or chromosphere is also high as compare to the photosphere. Then why we can see only photosphere? Because density of matter is too high as compare to the both. And how and why temperature of corona is high in comparison of both chromosphere and photosphere? The Sun's magnetic field is a primary explanation for the corona's high temperature. The Sun's rotating magnetic field permeates the corona. This creates magnetic reconnection events, which release a lot of energy. This energy warms corona plasma to extraordinary temperatures. Wave heating, particle acceleration, and magnetic reconnection may all contribute to the corona's high temperature. The corona's outer layers vary in temperature.
The corona gives off light in the ultraviolet and X-ray parts of the spectrum. It looks like a pearly white circle around the Sun during a total solar eclipse. The Sun's magnetic field shapes the corona and is also behind many of the things we see on the Sun, like sunspots, solar flares, and coronal mass ejections.
