Abundant blue stars, higher temperatures, Many Famous stars in folklore with cultural importance and Easily recognizable. Welcome to our post where we learn about Stars and other Astronomical Objects and structures, for most of you, Astronomy is a subject with hard mathematics and brain work but here we learn them with little to no use. Anyway, Thanks for coming here and We hope you'll enjoy this post while reading like many of our other posts.
Today in this post, we are going to talk about B-type Stars with some interesting facts. Without further ado let's get started.
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| Artist Impression : The B type Star |
Main Characteristics :
These stars bear mass between 2.1 to 16 Solar masses and 13.2 to 3.6 times wider than our sun, Temperature lies between 10,000 to 30,000 K and they glow in Bluish-white color. They are highly luminous, they can be 25-30,000 times more luminous than the sun. Lifespan is around a few tens of millions of years which is shorter than many other types of stars. Since they are so luminous, Many naked-eye stars belong to this category some of which have cultural importance we'll also discuss them in the course of the post. Their Fusion is powered by the CNO cycle which is an energetic method of Energy generation in Stars you can read more about The Fusion Methods in Stars in the other post Because it's not our objective here. Like O-type, They also become supernovas when they die but if these stars contain lower mass they can become massive White dwarfs.
They are powerful sources of ultraviolet radiation. Some B-stars rotate so fast that their shape is deformed. Like O-class, they are also uncommon but not as O-group, however, Still rare in our solar neighborhood (around 300 light-years) in fact, there is only one B-type Star called Eta Centauri.
Other Kinds of Blue Stars :
One thing you must know is that B-type Doesn't contain one kind of star instead some of its members could be born in other spectral groups, some will change their properties due to mass loss and become M-type Giant stars, some have evolved from Late O (O7, O8, O9) Stars when they would have lost their temperatures. That's why Some B-type Stars can change their spectral types. Likewise, their death is also different, we will learn about their death as we go further in this post.
Main Sequence stars :
When such stars are productive meaning They fuse Hydrogen and create Helium through the CNO cycle, we say the star is in the main sequence phase. Mostly this part is long as compared to other phases of the star's lifespan, an average B-type Star can last about a few tens of million years in this stage due to rapid Fuel Burning. In this phase like O Stars, they emit strong stellar winds and dangerous amounts of UVs which strip off the atmosphere of planets, can disrupt the formation of nearby stars and many other features are similar to O-type Stars.
Sometimes, when such stars form in clusters, a Large molecular gas cloud begins to collapse and trigger star formation and if it is making Massive Stars then the interaction of proto-stellar activities can divide the cloud into several pieces and create Late O and Early B (B0, B1, B2, B3) stars together in a cluster this is called OB association. If they are part of a Binary system, their gravitational influence can distort stars and eject the star from its origin at high speeds about 402,335 Km/h. such stars are called Runaway Stars. this can also happen by a supernova explosion, a black hole's gravity or in clusters where its members are interacting with each other.
Imagine The Star's core has converted all the hydrogen into helium then it contracts and the outer portion of the star will expand and it will go through many stages like Sub giant, Common Giant, Bright Giant, Blue loop and Supergiant phases but we aren't discussing them here in this post. You can refer to this post where we have provided plenty of descriptions and facts. However, you can see the images below which show some famous stars and their brief characteristics.
But it won't happen in some hundreds or thousands of years instead it will take at least some millions of years. When they produce helium, it accumulates in the central part of the core and conditions don't meet for the Fusion process, So it will stop for some time and the core begins to contract due to gravity which causes more particles to come together and increase the heat and the outer envelope expands little bit. But they have some hydrogen in the outer regions of the core and the temperature is very high. Therefore, The central region's heat will ignite the Hydrogen that lies outside of the core. Fusion Starts again, creating more helium and Star now has a source to cope with the gravity again. After some time, it will also exhaust. Then it will Fuse Helium inside the core and create Carbon and Oxygen, After some time it will also accumulate and Fuse when the Required conditions are met and produce Neon, then it fuses Oxygen and Silicon and finally creates Iron and Fusion stops, It may continue but Temperature, pressure and other condition are not enough. Theoretically speaking when the Core Fuses Iron, generated energy is not enough to sustain the star instead it requires much more energy that's why Massive stars stop here.
When the Iron deposits on the central part of the Core, Fusion Ceases and collapses owing to gravity and all the Burning layers implode and a shockwave is generated which tears apart the Whole star but all these devastating events happen in about some hours, the Star now explodes with extreme power which causes shine the star so brightly that it will appear brighter than all the stars of its galaxy. This violent explosion is called supernova. Its outer envelope scatters to several light years in space, along these remnants of the outer portion of the star all the elements which were produced inside, mixes with the gas cloud. The core shrinks to about 15-20 Km From some Billion Km and becomes a Neutron star or a black hole.
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| Supernova Remnant Nebula : The Massive Blue Star is dead and become a Neutron star |
Cultural Significance :
Alnilam (epsilon Orionis)
If you look at Orion Belt, in the sky where you see 3 stars appear aligned in a straight line, the Middle one is called Alnilam meaning string of pearls in Arabic. While Egyptians thought this was the resting place of Lord Osiris.
Shaula (lambda Scorpii)
This star's name comes from the Arabic Language which means tail, because it is found in Scorpion's Tail if you look at this constellation. In Indian astrology, This star is called Mula Nakshatra if someone is born in this period he will face an Extreme trial of fortune yet the person will be full of honesty and a truthful nature.
Algol (beta Persei)
What if our sun was a B Star :
It is an interesting point that many people are asking about it on the internet. Firstly, The earth is about 4.54 Billion years old and a regular B-type Lifespan is around a few tens of Million years therefore, at the place where the sun is, there would be a Neutron Star and if the star would massive enough, then a Black hole. However, if we think they exist together there is still no chance because B-type stars can interrupt the planetary formation by Strong Ionizing radiation and winds. But here, we will think it again as if our sun magically Transforms into a Regular B5 Type Star in just about 1 day then:
Effect on the world
Suppose, you wake up on a normal Morning and you see in the Newspaper that our sun is going hot at an exponential rate. When you look through your window you won't see anything but a White Flash. You will feel extreme heat since in the morning, Every piece of equipment, device, machine and infrastructure that uses applications of heat and Electricity will start to melt down because of the enormous temperature. Earth's night side will also face this kind of temperature but on smaller scale. It will cause extreme temperature differences and the weather will be very bad meaning Tornadoes, sandstorms and many more. At about 10 O'clock, no one will left alive, infrastructures will have been completely dismantled, metals will be turned into liquid form and the ocean's water will have reached the sky, accumulating for some time and then breaking into hydrogen and oxygen. A tremendous gust of stellar wind will shove it away into the space. Earth's atmosphere will completely vanish in some days and Earth will become a volcanic world.
Effect on solar system
Soon after turning our sun into a B-star, Mercury, Venus and Earth will begin to disappear due to a process called photo-evaporation in which, these planets will release radiation in enormous amounts and scatter their subatomic particles into Space. They will look like comets with long tails. After some time, The Jupiter and Gas giant will also start to die in such a way. Finally, our sun will appear from Hundreds of light years.
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| The B type Sun : The Earth and Venus (Long comet like Smoke Trail) |