10 of the Strangest Stars in the Universe

Ordinary, main-sequence stars are enormous balls of plasma held together by gravity and powered by fusion reactions deep within incredibly hot and dense cores. Our own Sun is a perfect example, but it’s an unremarkable object that’s not unlike millions of other stars in the Milky Way galaxy alone. However, just like everything else in the universe, stars come in many different breeds, each with distinct life cycles that can produce some truly astounding results. In this week’s listicle, I’m going to introduce you to 10 of the strangest stars in the universe, including some that have made us reevaluate our knowledge of physics.

#1. A Pulsar with a Planetary System

NASA/JPL-Caltech

Being all that remains of a star that’s gone supernova, a pulsar is a type of stellar remnant, but one that’s still intensely bright despite its size and radiates a spinning beam of light that looks a bit like that of a lighthouse. However, while pulsars are bizarre enough already, PSR B1257+12, also known as Lich, takes the weird to the next level by being host to no less than three of the most unusual extrasolar planets ever discovered. All that remains of a dead solar system, these planets have long had since their atmospheres stripped away by a supernova explosion, along with any life that may once have inhabited their punished surfaces.

#2. A Star Brighter than 8-million Suns

NASA

Never look at the Sun directly, especially when you’re using binoculars or a telescope. That’s what everyone tells you, and it’s some very solid advice if you want to avoid risking permanent eye damage. However, R136a1 is 8.7-million times brighter than the Sun, and that’s not even the only record it breaks. It also has the highest mass of any star so far discovered and, with a surface temperature of almost 50,300 °C, it’s one of the hottest. R136a1 lies at the centre of a starburst formation in the Large Magellanic Cloud, a satellite galaxy to the Milky Way some 163,000 light-years away.

#3. A Star that Keeps Mysteriously Dimming

NASA

Also known as Tabby’s Star, KIC 8462852 has been hitting the headlines and doing the rounds on social media most relentlessly in recent months. Located 1,480 light-years from Earth, the star is notable for its bizarre light fluctuations, which have lead many, perhaps rather overoptimistic, skywatchers to claim that it could be home to an alien megastructure such as a Dyson swarm or sphere. However, although Tabby’s Star remains one of the biggest astronomical mysteries of recent times, it seems rather more likely that its strange characteristics are down to a collision with a swarm of comets, a protoplanet or even another star.

#4. A Subgiant that Appears to Be Older than the Universe

ESA/Hubble

Popularly known as Methuselah’s Star, HD 140283 simply shouldn’t exist at all. The universe is 13.8-billion years old, but current theoretical models put Methuselah’s Star at some 14.5-billion years old, thus presenting something of a dilemma for cosmologists. Since the age of the universe seems pretty certain, the discovery of this star has had to make cosmologists rethink their entire theory on stellar evolution or otherwise find a mistake in their observations which, so far, they haven’t found any definitive solution to address the problem.

#5. A Red Supergiant that Would Extend Beyond Jupiter

Philip Park

If you placed the red supergiant UY Scuti in the middle of our solar system, in place of the Sun, its heliosphere would swallow Mercury, Venus, Earth, Mars and Jupiter, and even Saturn would be cooked, its skies absolutely dominated by the largest star ever discovered. It has a volume some 5-billion times greater than that of the Sun, and its radius is estimated to be around 1,708 times greater. However, just because UY Scuti is enormously large, don’t expect to see it with a naked eye, since it’s 9,500 light-years away, so you’ll ideally need a telescope with an aperture of 4 inches (10 cm) or greater to find it easily.

#6. A Red Dwarf That’s Barely a Star

NASA's Goddard Space Flight Center/S. Wiessinger

Red dwarf stars are the most common in the universe, accounting for over two thirds of all known stars. They’re small, dim and red compared to the Sun and, as such, there aren’t any that are visible to the naked eye. 2MASS J0523-1403 barely even makes the definition of a star, since it’s only just massive enough to fuse helium and hydrogen in its core. Located 40 light-years away, it’s the smallest known main-sequence star, its radius being only eight percent that of the Sun. However, while this tiny star might be relatively cool and faint, it will take trillions of years for its fusion reactor to run out of fuel, countless aeons after our own star has died.

#7. A Stellar Remnant the Size of Central Park

Kevin Gill

Neutron stars are already weird enough, not least because they’re so densely packed that a sugar cube of matter from them weighs millions of tonnes. The poetically named RX J1856.5-3754 is one of the smallest of them all, being no larger than New York’s Central Park. However, with a surface temperature of at least 400,000 °C and a crushing gravitational pull some two-trillion times stronger than that of Earth, it wouldn’t be such a great place for a stroll. Making matters even stranger, because of a phenomenon called gravitational time dilation, spending some 8 years on the surface of this stellar remnant would equate to 10 years for someone back on Earth.

#8. A Magnetar That’s the Strongest Magnet in the Universe

ESO/L. Calçada

Magnetars are a subcategory of neutron star characterised by their intensely strong magnetic fields, hundreds of millions times more powerful than anything that can be made by human hands. SGR 0418+5729, located around 6,500 light-years away, is one of the most exotic of all such stars, and it’s the strongest magnet so far discovered. Unusually, however, the magnetar has the lowest surface magnetic field of any stellar remnant of its type, but it appears to more than make up for it by magnetic energy stored within its core and projected from a relatively small surface region of 525-feet (160 metres) in diameter.

#9. A Hypervelocity Star Propelled by a Supernova

ESA/HUBBLE, NASA, S. GEIER

Almost all the stars in the Milky Way orbit the galactic centre; our own star does so every quarter of a billion years. US 708, however, is unbound, hurtling towards the edge of the galaxy at 26-million (43-million km) per hour. US 708 is a hypervelocity star that’s being booted out of its own galaxy, probably due to a supernova event that occurred relatively nearby. As such, the star is no longer gravitationally bound to the galactic core, and it’s moving faster than the galactic escape velocity. Consequently, US 708 will eventually move away from the Milky Way and become a rogue star floating through the vastness of intergalactic space.

#10. A Star that Flashes Red and Green

Palomar Observatory

Every autumn, in the northern hemisphere, skywatchers can train their telescopes onto one of the oddest-looking stars in the night sky. Twinkling red and green, this star is Capella, also known as Alpha Auriga, and it’s the sixth-brightest in the sky. However, what you’re actually seeing when you look up at the flashiest star in the night sky is no less than four stars. While they look like a single star to the naked eye, Capella is a star system sporting two pairs of binary stars which are gravitationally bound to each other at 10,000 astronomical units. Owing to its strange appearance, Capella is actually far better known for its influence on mythology than its being a star.