Exoplanet series – strange creatures

Keeping on with my exoplanet series. First of all, some updates in their number, that keep changing – due to new observations, discoveries and so on. As of April, 9th 2015, more than1900 exoplanets have been located (the latest statistics give 1953 planets in 1210 systems. Some are multiple planetary systems like ours – about  480. If you fancy keeping pace with them, just bookmark the page of the exoplanet.eu/catalog, which is also searchable for categories and planet details). After having gone through the essential features that define planets – size, temperature, distance, age – in previous posts, this one is aimed at examining some bizarre creatures you may find out there when looking around: because some of them really are (strange).

The diamond planet I have mentioned before was a pretty good introduction to this gallery, and only out of common characteristics has been included in that article: it would certainly qualify for a place here though.

puffy planet

Things get even weirder when we search the catalogue for outliers. Take HAT-P-1 for instance – nicknamed Puffy Planet with a reason. A massive world – just half of Jupiter – it is 1.76 times wider, and larger than what our current planet formation theories predicted.

Intriguing are also a variety of tilted planets – tilted not only with respect to their axis, like Uranus, but to their parent star’s equator, such as XO-3b, whose tilt is about 37 degrees. Something so unusual has only been observed so far with Pluto (no longer a full-fledged planet, I know: New Horizons mission might well change this too). A few theories have been formulated to explain how this has happened in the first place – have a look to this link for more.

Another strange case is when a planet is so close to its parent stars that its orbit – a terrestrial year, for comparison – is faster, say, that a day on Earth. Impossible? By no means. With a distance of only 740,000 miles from its sun, SWEEPS-10’s year lasts 10 hours. And this planet is not an isolated case, since it belongs to a category of worlds known as ultra-short-period planets (USPPs), “zippy planets” in jargon, all with orbital periods of less than 1 terrestrial day.

One Planet, Four Stars: The second known case of a planet in a q

“Star Wars-type Planets”, fictional planets described in SF films and novels and previously believed to be just that, pure fiction, have been found too, and not only planets around binary, triple or even multiple star systems (so far, the maximum found is an amazing four): also waterworlds seem to exist, such as GJ 1214b, a planet three times our Earth with a confirmed atmosphere.

And what about a world on the brink of doom – that’s it, a planet whose sun’s gravitational pull would eventually drag it in? This is the case of WASP-18, which is going to be under a lot of observations to track any orbital changes confirming its destiny. Even worse is the fate of WASP-12b, on its way to be literally *eaten* away under our eyes.

planet eaten awayAlso known to be the hottest known planet in the Milky Way, this ill-fated world is in the process of being stripped of its matter as the Cosmic Origins Spectrograph (COS) of NASA’s Hubble Space Telescope has recently revealed. As explained on NASA’s website, its story is fascinating. “The planet (…) is so close to its sunlike star that it is superheated to nearly 2,800 degrees Fahrenheit and stretched into a football shape by enormous tidal forces. The atmosphere has ballooned to nearly three times Jupiter’s radius and is spilling material onto the star. The planet is 40 percent more massive than Jupiter. This effect of matter exchange between two stellar objects is commonly seen in close binary star systems, but this is the first time it has been seen so clearly for a planet. We see a huge cloud of material around the planet, which is escaping and will be captured by the star. We have identified chemical elements never before seen on planets outside our own solar system.” According NASA’s estimates, the planet will only be around for another 10 million years: more than enough for some nice pictures.

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