Stars can be described as massive celestial bodies, often bright, moving heavenly features from afar. According to researchers, stars are mostly made up of Hydrogen and Helium, and these produce light and heat from the nuclear forces residing in their cores. Aside from the sun, the stars we see in the skies are light years away from the Earth. There are many things you should know about the stars, and they are explained below.
So, What do Stars Look Like When Close?
When viewed up close, a star will look like a giant ball of bright light in the center with scattered lights and a ring of colored lights surrounding it.
The First Detailed Image Of Stars
In 2017, a team of international astronomers produced the first detailed image of the surface of a giant star that was named Pi Gruis. The star was about 530 light-years from the Earth and was about the same mass size as the sun but was roughly 350 times larger and several thousand times brighter.
The star in focus- Pi Gruis can be described as a Red giant, a star in its last primary phase of existence. The star also gave the researchers a glimpse of what the sun will become at the end of its 5-billion-year lifespan.
The images of Pi Gruis taken revealed a nearly circular and dust-free atmosphere that has some complex areas of moving particles known as conventional cells. The report on the close encounter with the star was published in the 2017 Journal Nature.
According to the researcher, the transfer of heat in stars happens through convection, which is the transfer of heat due to the bulk movement of molecules within the liquid and gas components of the core parts of the star. The transfer of heat within the stars is responsible for several astrophysical processes, including energy-transportation, pulsation, and wind activities.
The researchers also discovered that Pi Gruis’s surface has very few convective cells, and each cell is about 75 million miles across, which is about a quarter of the star’s diameter. Just one of the cells would extend from the sun to the planet Venus.
When compared to the sun that has a surface containing about two million convection cells with an average diameter of is 930 miles, there seems to be a major difference in the amount of heat and energy generated between the Pi Gruis and the sun.
The vast major differences between these two stars can be explained by their varying gravities on the surfaces. Pi Gruis is one and a half times the size of the sun, and it is much larger. And that resulted in much slower surface gravity. The star also has a few but extremely larger cells or granules.
To complete this study, the researchers had used the Precision Integrated Optics Near-infrared Imaging Experiment, and it is known as “PIONIER.” This device was on the ESO’s Very Large Telescope Interferometer (VLTI). The experiment was conducted in Chile to observe the star.
According to one of the researchers, It was the first time the group had such a giant star that was imaged with such a high level of detail. The researchers agreed that there were limits to details they could see, and that was a result of the limitations of the telescope used. An interferometer was also used in the completion of the research. Lights from several telescopes were combined for the experiment; hence the limit of each telescope was overcome while the resolution of a much larger telescope was obtained.
Some Things You Should Know About Stars
There are lots of myths surrounding the birth of stars. People who practice mythology believed stars used to be demigods. The sizes of stars are also underrated, but in an actual sense, Stars are bigger than our planet in size, and some can be as big as three times the size of the sun. Stars do shine, and the color of the light from a star provides information about its temperature, size, age, and sometimes fate.
1. Stars Filter the Atmosphere
Gazing at the stars from the Earth is like looking at them through a water filter. The atmosphere can be very dense and may look empty without the stars in them. Since air is always moving, the light of a star will continue to appear as shimmering and shifting.
The atmosphere also makes the star seem dimmer than they are actually if we could see them directly from space. Stars do appear as round points of light, and the reason they seem to twinkle in images is that light diffracts in lenses and mirrors.
2. Stars Come in Different Colors
Contrary to popular belief that stars always appear white in color, there seems to be no truth in such belief. Try and stop and examine a star in the dark and moonless night. You should be able to spot the color differences among different stars.
The color of a star often depicts its surface temperature. For instance, the hottest stars often reflect the blue color on the surface, and white often reveals the next hottest stars. Yellow stars like the sun are next to the white and blue in high surface temperatures, while the red-colored stars tend to have the least hot temperatures on the surfaces.
Many red-colored stars are so dim that most people don’t see them from the Earth’s surface. Some stars are called the “brown dwarfs,” and they hardly emit any light, and they are almost invisible to anyone gazing from the surface of the Earth.
Most stars that don’t emit light often trap it, and they are black holes that constitute the leftovers of the hot and giant stars that exploded many years back.
3. Stars Come in Different Sizes
The primary reason why stars vary in brightness is that the hotter stars emit more heat and energy than others. Another reason for differences in brightness could be the differences in their sizes- the bigger stars shine brighter than smaller ones.
Betelgeuse, which is a star located in the constellation Orion, shines bright with a red light that is visible on a telescope. This star seems to appear bright to use because it is quite huge, much bigger than many other stars. If this star takes the place of the sun, its brightness will extend to planet Jupiter, and that is how bright it can be.
White dwarf stars, on the other end, have similar sizes to that of the Earth, even though they are some of the hottest objects in the sky. Dwarf stars are known to be remnants of dying stars and are often surrounded by ghostly gas formations referred to as “Planetary Nebula.”
4. Distance and Magnitude
Distance from the Earth’s surface can also make some stars appear brighter. Astronomers have ranked the brightness of stars before, as viewed from the Earth, and then assign them unique numbers referred to as “Apparent magnitude.” The smaller the magnitude, the brighter the object appears; hence those with smaller magnitude numbers tend to be brighter than those with larger numbers.
The researchers have also developed some other measures to rank stars according to their brightness in comparison to others. The absolute magnitude number describes how bright a star will appear if were some 32.6 light-years away from the surface of the Earth.
The sun, for instance, with an apparent magnitude number of minus 26.7, remains the brightest object in the sky, though its absolute magnitude number is a mere 4.7. If the absolute magnitude of the sun were to be 26.7, then it would be much more visible than what we currently see.
What Are The Causes Of Flickering Stars?
Flickering or twinkling is noticed by everyone, especially when we look into the sky at night. The twinkling is not caused by the properties of the stars themselves but by the atmospheric disturbances that bend light from the stars.
Light bends when it passes through a medium, and that is referred to as refraction. The changes in the medium the light passes through can change the degree to which the light is refracted. There is turbulence in the Earth’s atmosphere that is caused by the shifting layers of air at different temperatures and densities.
Consequently, the light passing through the atmosphere will naturally be refracted by regions with different densities. This explains why the light you see from the stars with the naked eyes gets shuffled through the Earth’s atmosphere, and you will call it to twinkle.
The higher the density of the medium and the faster the travel speed of light, the more twinkles you will notice. The twinkling of stars tends to reduce when light travels through a less dense medium. As expected, the larger the size of a star, the more it twinkles because the medium through which light travels around it is larger.
