There are different types of stars out there in universe. Some are called giant stars, others are bigger and are known as supergiants. There’s yet another category known as hypergiants. Our Sun belongs to none of the categories. It is just a plain and simple star. However, when we talk of huge stars, things can become a little baffling because of the measurements that astronomers use. For example, a hypergiant star may be the largest star in terms of size but it may not be the most massive star in terms of mass. The R136a1 is a typical example. It is the most massive star out there in our known universe but not the largest one by size. However, it is still a hypergaint. Let us learn 22 interesting R136a1 star facts and find out what makes it a special one in the catalog of universe. Ready?
Interesting R136a1 Star Facts: 1-11
1. Though this star is popular by its not-so-charming name R136a1, its real name is RMC 136a1.
2. In 1960, astronomers of Pretoria’s Redcliffe Observatory looked at the Tarantula Nebula and observed a central star that they catalogued as RMC 136.
3. In 1979 however, astronomers used ESO’s 3.6 meter telescope and identified that RMC 136 was actually made of three stars that were named as R136a, R136b and R136c.
4. Astronomers were still not happy with results and in 1985 Weigelt and Beiber made use of speckle interferometry to figure out that R136a was not really a single star. It was in fact a cluster of 8 stars with R136a1 being the brightest of all.
5. Finally Hubble Space Telescope was launched which then managed to figure out that RMC 136 was a cluster of 200 stars which were highly luminous by nature.
6. Finally in 2010, it was confirmed that R136a1 was THE BRIGHTEST and THE MOST LUMINOUS star in RMC 136 star cluster.
7. So essentially, RMC 136 is the primary cluster, at the core of which sits the R136a cluster of which R136a1 is the brightest and R136a2 being the second brightest star in the R136a cluster.
8. Astronomers estimate that the R136a1 sits at a distance of 163,000 light years (50 kiloparsec) from Earth.
9. The question here is, ‘how big is this star’? Well, the R136a1 is not the biggest one out there by size but it is THE MOST massive star known to us so far. It has a radius which is 30 times bigger than our Sun and it has 265 times more mass than Sun.
10. Though it is at a distance of 50 kiloparsec from us, it is actually our neighbor, sitting in the Dorado constellation of the satellite galaxy known as Large Magellanic Cloud. Satellite galaxy is a galaxy that orbits our Milky Way Galaxy.
11. Scientists classify this hypergiant as a Wolf-Rayet star. A Wolf-Rayet star is a heterogeneous star with broad and prominent emission lines. Such a star has very strong stellar winds, heavy elements on surface and extremely high temperature.
Interesting R136a1 Star Facts: 12-22
12. R136a1 has extremely high temperature of 53,000-56,000 Kelvin.
13. Scientists say that massive stars like this one usually belong to a binary star system. However, the R136a1 does not have a companion star. This means that does not belong to a binary star system.
14. Scientists have figured out that this hypergiant is actually losing mass at a very fast rate. According to estimates, the star is losing mass at the rate of 3.21 × 1018 kg/s. At this rate, this star actually losses a billion times more mass than our Sun in a single year.
15. According to scientific calculations, R136a1 has probably lost mass equivalent to 50 M☉ since its formation. M☉ stands for ‘Solar Mass’.
16. The reason why the star loses such huge amounts of mass is the high speed stellar wind that reaches the speed of 2,600 ± 150 km/s. Such high speed wind is caused by extremely intense electromagnetic radiations emanating out from the photosphere (the outer shell of the star from which light is emitted).
17. The problem with R136a1 is that material from its outer shell (photosphere) accelerates away with a force way stronger than what its surface gravitational pull is capable of retaining back.
18. The R136a1 is extremely luminous. In fact, it is the most luminous star know to us so far. Its luminosity stands at 8,000,000 L☉. L☉ stands for ‘Solar Luminosity’.
19. Explaining in simpler words, if the R136a1 replaces our Sun, it will be outshining the Sun by 94,000 times! This star shines so brightly that it radiates more energy in just 5 seconds than what is radiated by our Sun in 365 days!
20. Scientists say that the R136a1 uses CNO cycle type fusion reaction to hydrogen atoms into helium atoms because the core temperature of the star is extremely high.
21. According to experts, this star is very young, possibly a million years old as compared to 4.5 billion years of age of our Sun.
22. R136a1, scientists estimate, is not going to last for long. Its massive size and intense luminosity indicates that it will burn out it fuel very quickly and given its nature, it will inevitably become a black hole.
Sources: 1, 2