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The `hot Jupiter' extra-solar planet Qatar-1b
Qatar-led International Team Finds Their First Alien World
Qatar-1b is a gas-giant planet, 1.1 times more massive than Jupiter
and with a diameter 1.2 times that of Jupiter. It orbits an orange dwarf
star (named Qatar-1 in honour of the discovery, catalogue number
3UC311-087990) which is located 170 parsecs (550 light-years) from
Earth in the northern constellation of Draco. At this distance, the host
star appears about 200 times fainter than the faintest stars visible to
the unaided human eye on a clear moonless night.
The planet’s distance from its host star is just 0.023 times the Earth’s
distance from the Sun. It completes a full orbit every 34 hours.
Although the host star is smaller and about 800C cooler than the Sun,
the planet’s close proximity gives it a searing day-side temperature of
1100C.
The large optics of the Alsubai Project cameras are specifically
designed to allow many more small red stars like Qatar-1 to be
surveyed for planetary transits. The small size of such stars makes it
easier to detect the dips in light caused by planets smaller than
Jupiter passing in front of them. A key aim of the project is to discover
close-orbiting planets with sizes between Neptune (3.9 Earth radii)
and Saturn (9.4 Earth radii), which are very difficult to detect with
smaller survey instruments.
The left panel shows the size and orientation of Qatar-1b’s orbit
around its host star. For comparison, the silhouette of Jupiter against
the Sun is shown to the same scale.
Star map centred on the location of Qatar-1 in the northern sky.
Prof Andrew Cameron
Prof Keith Horne
Scottish Universities Physics Alliance
University of St Andrews