5. The Planet That Should Have Been Swallowed
Wasp 18 is 330 light years away in the Phoenix constellation, and about 25% more massive than our sun. This is another entry where not the star itself, but what orbits it, is the real mystery.
In 2009, Coel Hellier of Keele University discovered that Wasb – 18 had a planet. Dubbed Wasp–18b, the planet is slightly bigger than Jupiter, but has about 10 times its mass. This is just below the mass that would make it a brown dwarf, which is a star that failed to initialize. What puzzles astrophysicists is that the planet orbits less than 2 million miles from its parent star. By comparison, Mercury is nearly 36 million miles from our sun.
Wasp-18 is so close to its parent, that it completes its orbit in less than 23 hours, and its surface temperature is around 4,000 degrees Fahrenheit (2,200 Celsius). Being so close, the planet should eventually fall into its sun – yet it has survived already for about 680 million years. Given the mass of the star it orbits, this planet should have been consumed long ago. How a planet was able to form and remain in a location where planets were thought unable to exist, is a question that continues to perplex astronomers.
4. The Stardust That Found Its Way Home
Since PSR B1257 +12 is a remnant of a supernova explosion, scientist never expected to find planets anywhere near it. But they found an entire solar system. A total of three planets and one dwarf planet orbit this pulsar. Thinking they must be common, scientists began looking at other pulsars for planets: however, only one other pulsar was confirmed to have a single planet orbiting it, showing that they are indeed extremely rare.
The process by which such planets are able to form is still not well understood. The most accepted theory is that the planets formed a little like our own – from a planetary disk that originally surrounded the star. However, any planet-making material and dust should have been thrown billions of miles out into space by the supernova explosion. How the gas and dust was able to return to the remaining ulsar, become tidally locked, and contain enough material for the formation of a whopping four planets – remains a mystery.
3. The Disco Star
V838 Monocerotis is located in the constellation Monoceros, which is about 20,000 light years from earth, and was at one point considered one of the largest stars in the universe.
In 2002, the brightness of the star shot up suddenly. It was thought to be a simple nova, which is what happens when the remaining core of a dead star (known as a white dwarf) accumulates too much hydrogen gas from a neighboring star, causing a fantastic explosion. The star dimmed after a couple weeks, as expected, and scientists put it in the record books as a nova.
But less than a month later, the star burst into light again. Since the time period between the explosions was too short to be caused as two separate novas, astronomers were puzzled and took a closer look. It was then they discovered their problem: there was no white dwarf. The star had simply erupted by itself – and it repeated this process of brightening and dimming several times over the next few months. During its brighest eruption, the star became a million times brighter than the sun, and one of the brightest lights in the sky.
Typically, stars brighten slightly before their death – but measurements indicated that the star was only a few million years old, a mere toddler in star years. When the Hubble Telescope captured an image of the star after the eruptions, a large cloud of gas and debris was seen accelerating away from the star. One theory is that the star had collided with something unseen, such another star or planet, but scientist are still puzzled by this now decade-old mystery.
2. The Rogue Planet
CFBDSIR 2149 – 0403 is classified as a brown dwarf. These have failed to initialize nuclear fusion in their cores, and develop into real, burning stars. While characterized as an AB Doradus star, due to its size and mass, many others characterize it as a gas giant. This would make it a planet without a parent star, which has been theorized but only rarely observed.
Only four possible candidates for the title of ‘rogue planet’ are known to exist, the one in question being the closest to earth at an estimated 130 light years. Without a large star to orbit, the motion of the plant is influenced by other stars in the AB Doradus star group. This doesn’t mean that it travels through space in any sort of straight line – a common misconception about rouge planets. But just how a planet is able to go rogue remains a mystery.
1. The Vanishing Stardust
TYC 8241 2652 is located 450 light years away in the constellation Centaurs. It is believed to be around the same size as our sun – but a mere child, at 10 million years old, compared to our 4.5 billion-year-old star. From 1983 to 2008, astronomers searched a bright ring of dust around the star for possible planet formation, believing they were getting some insight into how our own solar system formed. But when the star was due for a check up in early 2009, astronomers were astonished: when they looked through their telescopes, they saw nothing but the star itself. The once-visible, glowing disk of dust was gone. It did not leave behind any planets, or any signs as to where it had gone; it had quite simply vanished. Scientists were baffled. When asked about it, astronomer Carl Melis simply stated, “We don’t have a really satisfactory explanation to address what happened around this star.”