光球层 The Photosphere

光球层是恒星们可见的“表面”。

The photosphere is the visible ‘surface’ of the star.

由于恒星其实是一团巨大的等离子体热气（由电子和离子组成的带电气体），它们不像地球那样有清晰的固体表面。

Since stars are giant balls of plasma (electrified gas made of electrons and ions), they don’t not have a defined solid surface like the Earth.

随着核聚变过程在恒星的核心发生，产生的光能射线会向外慢慢的扩散。过程中，它们会与沿途的粒子一次又一次地碰撞，这就减慢了它们的穿越速度，降低了它们的能量。

As the fusion processes happen in the center core of the star, the light energy rays created slows diffuses outwards. On their ways, they would collide over and over with particles in the way, which slows down their travel and reduced their energy.

最后，经过数百万年（太阳中的光子大约需要120万年），光子最终才会到达外层的较低密度层，在那里它们终于能够自由地飞向太空了。

Finally, after millions of years (~1.2 million years for the Sun), the photons finally

reach the outer less dense level, where they will be able to escape freely into space.

所以，这就是我们看到恒星发光的“表面”—— 光球层的地方。

So, this is the level where we see the glowing ‘surface’ of the star – the photosphere.

不同大小的恒星在其生命的不同阶段，光球层的温度也不同。但我们知道太阳的光球温度为5500摄氏度，比其核心的1000万度要低得多。

The temperature of the photosphere varies with different sized stars at different stages of their lifetime.However, we know that the sun has a photosphere of ~5500 Celsius, which is much cooler than its core of 10 million degrees.

由于太阳黑子（扰动磁场的指示器）的存在，表面不同地区的温度会有所不同，有些区域温度可低至3000-4500度。

The temperature would vary at different areas due to the sunspots (indicators of disturbed magnetic fields), where temperatures can be as low as 3000-4500 degrees.

研究还发现，太阳的光球层的温度出奇地低于太阳的大气层。太阳大气层作为光球层上方的一个三层结构，温度也可以达到几百万摄氏度。

It also found the photosphere temperature of the Sun is surprisingly lower than the Sun’s atmosphere, which is the three-layered structure above the photosphere. There, the temperature can also reach up to a couple millions of Celsius.

图为太阳的整体结构，其中橘色外层最厚的区域为我们这里说的光球层

The inner structure of the sun, the photosphere layer here is the outer think orange coloured section

图片NASA 官网

中英文内容为原创

Pictures from official website of NASA

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