Huge mystery object at the heart of our galaxy

Risingbd Desk: Astronomers have discovered a massive alien world circling a star located 22,000 light years away, at the centre of the Milky Way's bulge.

The object, dubbed OGLE-2016-BLG-1190Lb, is 13 times the size of Jupiter and is so vast that experts are unsure whether it is even a planet.

Experts used Nasa's Spitzer Space Telescope and the light-warping effects of gravity to uncover the mysterious celestial body.

Although it is orbiting its own star, researchers say 'Planet X' may in fact be a failed star, known as a brown dwarf.

An international team of researchers, led by Yoon-Hyun Ryu of the Korea Astronomy and Space Science Institute in Daejon, South Korea, reported the find in a paper published on the online print repository Arxiv.org.

It was made using a technique known as microlensing, that facilitates the discovery of distant objects by using background stars as flashlights.

OGLE-2016-BLG-1190Lb was discovered in June 2016 by the Optical Gravitational Lensing Experiment (OGLE) collaboration.

OGLE is a Polish astronomical project based at the University of Warsaw, which is searching the universe for dark matter and extrasolar planets.

It uses the five foot (1.3 metre) Warsaw telescope mounted at the Las Campanas observatory in Chile.

The team used readings taken from Nasa's Spitzer space telescope which has uncovered a number of microlensing events, to narrow their search.

Writing in the paper, its authors said: ‘We report the discovery of OGLE-2016-BLG-1190Lb, which is likely to be the first Spitzer microlensing planet in the galactic bulge/bar.

'It is precisely measured to be right at the edge of the brown dwarf desert.

‘This is somewhere between 13 and 14 Jupiter masses. OGLE-2016-BLG-1190Lb has about 13.4 Jupiter masses.

'Since the existence of the brown dwarf desert is the signature of different formation mechanisms for stars and planets, the extremely close proximity of OGLE-2016-BLG-1190Lb to this desert raises the question of whether it is truly a "planet".'

Brown dwarfs are thought to be the missing link between planets and stars, with masses up to 80 times that of Jupiter. 

But their centres are not hot or dense enough to generate energy through nuclear fusion the way stars do.

OGLE-2016-BLG-1190Lb's mass puts it right at the deuterium burning limit, the conventional boundary between planets and brown dwarfs.

Scientists have found that, for stars roughly the mass of our sun, less than one per cent have a brown dwarf orbiting within three AU.

One AU is the distance between Earth and the sun. This phenomenon is called the 'brown dwarf desert.'

OGLE-2016-BLG-1190Lb orbits its parent star approximately every three years at a distance of about two AU.

Source: The Mail



risingbd/Nov 13, 2017/Mukul