Extraordinary claims. Ordinary investigations.

Seeing Exoplanets – and much more

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Scientists from the University of Toronto announced last week what may be the first direct image of an extrasolar planet orbiting a star similar to our own Sun. The pale orange dot was imaged around the 1RXS J160929.1-210524 star, some 500 light-years from Earth, and is around eight times bigger than Jupiter.

There’s still no confirmation that the object is indeed going around the star — if it is, then besides being an extrasolar planet, it’s also an intriguing find due to its size and huge distance from the star — more than ten times farther than Neptune is from the Sun. Current theories to the formation of planetary systems would have some trouble to explain such a huge planet so far from its star. Perhaps something like this game?

Fact is, there are now more than 300 known extrasolar planets throughout the Universe. Almost all of them were detected indirectly, but there were quite a few possible direct images before this one, going from the TMR-1 ten years ago to the 2M1207b announced in 2004. This latest one could be the first exoplanet detected directly around a star similar to our Sun.

This is all the more amazing, since two decades ago, we didn’t know any, not even one single planet beyond our solar system. In 1988, Canadian astronomers announced the discovery of a planet around Gamma Cephei, but the data was uncertain, and it was confirmed only many years later. It was only in 1992 that a planet was confirmed around pulsar PSR 1257+12, and then finally in 1995 Mayor and Queloz from University of Geneva publicized the definitive discovery of a planet in orbit of the 51 Pegasi star.

Ever since, with exoplanet detection receiving more attention (i.e. funding), we detected these hundreds of planets and estimate that more than 10% of the sun-like stars we see in the sky have planets going around. Probably much more than that.

In another astronomical news this week, researchers from the Supernova Cosmology Project, using data from the Hubble space telescope, reported the discovery of a "mysterious" object.

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Detected initially in Februrary 2006 in an "empty" area of the sky, outside any observable galaxy, the object gradually increased its brightness more than 120 times in three months. Only to decrease it in the next months and vanish again. Spectral analysis showed that "in addition to being inconsistent with all known supernova types, is not matched to any spectrum in the Sloan Digital Sky Survey database" of vast numbers of objects.

"We suggest that the transient may be one of a new class", said the astronomers who will publish their work in the Astrophysical Journal. That is, they may have found a completely new kind of object in the Universe. Among billions and billions

Astronomy is still a field full of mystery and surprises, which are only reinforced by our vast knowledge extending billions of light-years from our home planet. In particular, the latest direct image of an extrasolar planet was captured from a ground telescope, in Hawaii!

In a recent discussion, astrobiologist Jill Tarter from project SETI mentioned the series of intriguing signals recorded by the project, including a short pulse detected last year. Asked if she thought the signal was artificial, she pondered that:

"like Jocelyn Bell with the pulsars, when we come up with anomalies, we ought not to totally ignore them. If you can’t say that it’s black holes colliding or some other phenomenon, then let’s go back to thinking about some technologist somewhere who figured out how to do this."

In fact, it’s unlikely the object detected by the Hubble is artificial, and despite the hundreds of exoplanets detected, our technology is still a distance away to detecting really Earth-like planets. Neither has SETI been able to confirm any of its anomalous signals.

Nevertheless, we can hope all of these matters will be answered by another one. A matter of time. If only we search for it, of course. [h/t TDG]

References 
Direct Imaging and Spectroscopy of a Planetary Mass Candidate Companion to a Young Solar Analog;
Discovery of an Unusual Optical Transient with the Hubble Space Telescope.

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