Exoplanet's hot spot in wrong place

On Sale Now!

		The June 2013 issue of Astronomy Now is on sale! Order direct from our store (free 1st class post & to UK addresses). The Astronomy Now iPad/iPhone editions are now available worldwide in the iTunes store.

Top Stories

		Earthshine used to test life detection method ...By imagining the Earth as an exoplanet, scientists observing our planet's reflected light on the Moon with ESO's Very Large Telescope have demonstrated a way to detect life on other worlds... READ MORE Solid buckyballs discovered in space ...Astronomers using NASA’s Spitzer Space Telescope have detected a particular type of molecule, given the nickname “buckyball”, in a solid form for the first time... READ MORE Steamy water-world gets the Hubble treatment ...Hubble Space Telescope observations of a 7 Earth-mass planet find an unusual water-rich world swathed in a thick, steamy atmosphere... READ MORE

Exoplanet's hot spot
in wrong place
DR EMILY BALDWIN
ASTRONOMY NOW
Posted: 20 October 2010

Observations of a distant hot-jupiter by NASA's Spitzer Space Telescope reveal a hot spot in the planet's atmosphere in an unexpected location.

Andromedae b orbits tightly around its star with one face permanently locked towards the Sun. The hottest part of a tidally locked planet's atmosphere is usually offset by a few degrees as a response to winds arising from the temperature difference blowing hot air to cooler regions, but for this gas giant, the hot spot is offset by a staggering 80 degrees. That is, the hot region is essentially on the 'side' of the planet instead of in the direct line of sight of the solar heating.

This graph shows how the hot spot was located, by measuring the total infrared light of the planet and star – when the hot spot faces Earth, the total brightness of the system increases. The black line shows the response if the hot spot was located in the middle of the Sun-facing side of the planet. The light curve (yellow line) was observed, offset by 80 degrees. Image: NASA/JPL-Caltech/I.J.J Crossfield (UCLA).

“We really didn’t expect to find a hot spot with such a large offset,” says Ian Crossfield, lead author of research soon to be published in the Astrophysical Journal. “It’s clear that we understand even less about the atmospheric energetics of hot Jupiters than we thought we did.”

One explanation is extremely fast winds – perhaps even supersonic winds – that distort the temperature patterns of the planet's atmosphere by triggering shock waves in the atmosphere. Another suggestion is that magnetic field interactions between the star and planet could play a role.

Artist impression of the hottest part of Andromedae b curiously located towards the 'dark' side of the planet. Image: JPL.

“This is a very unexpected result,” adds Spitzer project scientist Michael Werner. “Spitzer is showing us that we are a long way from understanding these alien worlds.”

Andromedae b speeds round its host star once every 4.6 days, and was discovered via the radial velocity technique – the tell-tale wobble it induces in the star's motion as it moves towards and away from the observer.

Infinity Rising

This special publication features the photography of British astro-imager Nik Szymanek and covers a range of photographic methods from basic to advanced. Beautiful pictures of the night sky can be obtained with a simple camera and tripod before tackling more difficult projects, such as guided astrophotography through the telescope and CCD imaging.

U.K. STORE

E.U. STORE

U.S. & WORLDWIDE STORE

Hubble Reborn
Hubble Reborn takes the reader on a journey through the Universe with spectacular full-colour pictures of galaxies, nebulae, planets and stars as seen through Hubble's eyes, along the way telling the dramatic story of the space telescope, including interviews with key scientists and astronauts.
U.K. STORE
E.U. STORE
U.S. & WORLDWIDE STORE

The Planets
From tiny Mercury to distant Neptune and Pluto, The Planets profiles each of the Solar System's members in depth, featuring the latest imagery from space missions. The tallest mountains, the deepest canyons, the strongest winds, raging atmospheric storms, terrain studded with craters and vast worlds of ice are just some of the sights you'll see on this 100-page tour of the planets.
U.K. STORE
E.U. STORE
U.S. & WORLDWIDE STORE

3D Universe
Witness the most awesome sights of the Universe as they were meant to be seen in this 100-page extravaganza of planets, galaxies and star-scapes, all in 3D!
U.K. STORE
E.U. STORE
U.S. & WORLDWIDE STORE

Mars rover poster

This new poster features some of the best pictures from NASA's amazing Mars Exploration Rovers Spirit and Opportunity.

U.K. STORE

E.U. STORE

U.S. & WORLDWIDE STORE