Release Date: 25 September 2006  
Ref.: PN 06/36
Issued by:
Peter Bond
RAS Press Officer
10  Harrier Close, Cranleigh,
Surrey GU6 7BS
Tel: +44 (0)1483-274047 /  268672

RAS Web:



Finding planets that pass in front of their parent stars is so  important to
understanding how planets form that the European Space Agency will  shortly
launch the 35 million Euro COROT satellite to find them. But a team of  UK,
French and Swiss astronomers is already paving the way from the ground, with
today's announcement of the discovery of two new Jupiter-sized planets around 
stars in the constellations of Andromeda and Delphinus. They are among the 
hottest planets yet discovered. Their atmospheres are slowly being whipped away 
into space by the searing radiation from their parent stars.

These  planets are the first to be found during the UK-led SuperWASP (Wide
Angle Search  for Planets) programme. Using wide-angle camera lenses, backed by
top-quality  CCD cameras, the SuperWASP team have been repeatedly surveying
several million  stars over vast swathes of the sky, looking for the tiny dips
in the starlight  caused when a planet passes in front of its star. This is
known as a  transit.

Confirmation of the new finds came earlier this month when  the team joined
forces with the Swiss and French users of SOPHIE, a powerful new  French-built
instrument at the Observatoire de Haute-Provence. SOPHIE was able  to detect a
slight wobble in each star's motion as the planets orbited around  them.
Together the two types of observation confirmed the existence and nature  of the

"The partnership between the two instruments is  particularly powerful -
SuperWASP finds candidate planets and determines their  radii, and SOPHIE
confirms their nature and weighs them," said Dr. Don Pollacco  (Queen's 
University Belfast), the SuperWASP Project  Scientist.

"We're delighted that in its first 4 nights of  operation, SOPHIE has
detected SuperWASP's first two new planets," said  Professor Andrew Collier 
Cameron (University of St. Andrews), who led the  international follow-up 

Approximately 200 planets around  other stars are now known, but almost all
of them were discovered using large  telescopes costing tens of millions of
pounds. This requires laborious study of  one star at a time, in the hope of 
finding stars with planets around them. 

In contrast, the SuperWASP telescopes look at hundreds of  thousands of stars
at a time, allowing all those with transiting planet  candidates to be
identified in one go.

In only a dozen or so of the  known systems has a planet been observed to
pass in front of its star. Although  the number of known 'transiting exoplanets'
is still very small, they hold the  key to the formation of planetary
systems, and an understanding of the origin of  our own Earth. They are the only
planets whose sizes and densities can be  determined reliably.

The stars around which the new planets are  orbiting are both similar to the
Sun. One is a little hotter, brighter and  bigger, whilst the other is a
little cooler, fainter and smaller. The larger  star, in the constellation of
Andromeda, is over 1,000 light years away. The  smaller star, in the 
constellation of Delphinus, is only about 500 light years  distant. Although 
both stars are too faint to be seen with the naked eye, they  are easily 
detectable with a small telescope.

The planets  themselves, known as WASP-1b and WASP-2b, are of a type known as
'hot Jupiters'.  They are both giant gas planets, like Jupiter, the largest
planet in our solar  system, but they are much closer to their parent stars.

Whilst Jupiter is nearly  800 million km from the Sun and orbits it once every
12 years, WASP-1b is only 6  million km from its star and orbits once every
2.5 days, WASP-2b is only 4.5  million km from its star and orbits once every 2

The very  close orbits mean that these planets must be even hotter than the
planet Mercury  in our solar system, which is nearly 60 million km from the Sun
and has a  surface temperature of over 400 degrees Celsius. WASP-1b's 
temperature is estimated to be over  1800 degrees C. Both planets show signs 
that they are losing their atmospheres to  space.

The SuperWASP team is currently planning follow-up  observations of the two
new planetary systems with the Hubble Space Telescope  and the Spitzer Space
Telescope in order to measure more accurately the sizes  and temperatures of
the planets, and also to look for indications of any other  planets in these
systems. SuperWASP is expected to find dozens more transiting  planets over the
next few years.

A paper detailing these results  has been submitted to the journal Monthly
Notices of the Royal Astronomical  Society.


At an international  conference today at the Max Planck Institute for
Astronomy in Heidelberg, a team  of astronomers from the UK, the Canary Islands,
France and Switzerland will  announce the discovery of two new planets orbiting
around other stars. (The  conference talk by Dr. Rachel Street is scheduled for
11:50 a.m. local time).  The two planets, named WASP-1b and WASP-2b, were
identified with the aid of the  world's biggest planet-hunting survey 
telescope, known as SuperWASP, which is  located on the island of La Palma. 
The planetary nature of the discoveries was  established using a new instrument,
known as SOPHIE, at the Observatoire de  Haute-Provence. These two telescopes 
have just begun joint operations and found  the two new planets in their 
respective inaugural observing  seasons.

While no telescope could actually see planets around other  stars directly,
the passage or transit of the planet across the face of star can  block out
about 1% of the parent star's light, so the star becomes slightly  fainter for 
a few hours. In our own solar system a similar phenomenon occurred  on 8th June
2004, when Venus transited across the Sun's disk.

The  SuperWASP telescopes take repeated images of hundreds of thousands of
stars in  one snapshot, building up a record of how each star's brightness
varies with  time. By searching through the data for stars which 'wink',
candidates for those  harbouring planets are identified. These candidate stars 
are then observed  individually to confirm the planet detection, using the 
famous telescope at  Observatoire de Haute-Provence where the first historic 
exoplanet discovery was  made in 1995 by team members Michel Mayor and Didier 


The SuperWASP (Wide Angle  Search for Planets) project operates two camera
systems - one in La Palma in the  Canary Islands and one at Sutherland
Observatory, South Africa. These telescopes  have a novel optical design 
comprising eight scientific cameras, each resembling  in operation a household 
digital camera, and collectively attached to a  conventional telescope mount. 
SuperWASP has a field-of-view some 2000 times  greater than a conventional 
astronomical telescope. The instruments run under  robotic control and are 
housed in their own customised  building.

The eight individual cameras on each mount are small by  telescope standards -
the lenses are just 11 cm in diameter - but coupled with  state-of-the-art
detectors and a sophisticated, automated data analysis  pipeline, they are
capable of producing images of the entire sky, several times  per night, and
detecting several hundred thousand stars in a single  snap-shot.

One nights' observing with SuperWASP generates a vast  amount of data, up to
60 GB - about the size of a typical modern computer hard  disk (or 100
CD-ROMs). These data are then processed using sophisticated  software and stored
in a database at the University of  Leicester.

By repeatedly observing the same patches of sky, over  and over again with
the SuperWASP telescopes and measuring accurately the  brightness of all the
stars detected, the astronomers build up 'light curves' of all the objects to
monitor how their brightness varies with time. 

For those stars with planets in orbit around them, and in which  the orbits
are seen almost edge-on, dips in brightness (about 1%) occur when the  planet
passes in front of the star. In effect, the stars are winking to tell us  they
have planets. The duration and depth of the dip in the light curve allow  the
radius of the planet to be measured.

The data from which the  two WASP planets were discovered were obtained in
2004, when the northern  SuperWASP telescope was operating with just five
cameras. Both SuperWASP North  and South are now operating robotically with
their full complement of eight  cameras each. The initial haul of planets 
discovered promises even greater  catches that will place our understanding 
of these bizarre planets on a secure  statistical footing.


Having  detected stars with exoplanet candidates orbiting them, the
detections are  confirmed using a new instrument - the SOPHIE spectr ograph - 
at the Observatoire  de Haute-Provence. The observations reported here were 
obtained during the first  week's operation of this new instrument.

As planets orbit around  their host stars, the star itself is tugged around
in a small orbit by the pull  of the planet. This tiny 'wobble' is detected
using the Doppler effect. The  spectrum of the star contains many absorption
lines produced in the star's  atmosphere. These spectral lines occur at
characteristic, accurately known  wavelengths. However, as the star moves under 
the influence of the orbiting  planet, so the spectral lines shift backwards 
and forwards in wavelength by tiny  amounts.

The SOPHIE spectrograph allows these tiny wavelength  shifts to be measured
very accurately. In the case of the two planets discovered  here, the measured
Doppler shifts amount to less than 0.0003 nanometres in  wavelength, which
corresponds to speeds of less than 200 metres per  second.

Similar transits to those observed by SuperWASP could also  be produced by
low mass stars, so it is essential to measure the Doppler shift  in order to 
'weigh' the transiting object and distinguish between the two  possibilities. 
The analysis of the Doppler shift allows the planetary nature of  the 
transiting companion to be secured and its true mass to be determined.  
Combined with the radius determination, it provides the density of the planet,
which is crucial information for the study of internal structure of  exoplanets.


The SuperWASP facility  consists of: Solid State Detectors (CCDs) from Andor 
Technology (Belfast); Canon  Optics; Optical Mechanical Inc. Robotic Mount;
Customised Enclosure by Jeremy  Rainford of Gendall Rainford Products
(Cornwall); Liebert Hiross  Air-conditioning; GPS Time service by Garmin; 
Lightning protection equipment by  Farrell Engineering (Dublin); Computing by 
Dell, 3Com and APC. Further technical  details can be found at the project 
home  page.


The  SuperWASP facility is operated by the WASP consortium, which consists of
 representatives from the Queen's University Belfast, the University of
Cambridge  (Wide Field Astronomy Unit), Instituto de Astrofisica de Canarias, 
the Isaac  Newton Group of Telescopes (La Palma), the University of Keele, the
University  of Leicester, the Open University, the University of St Andrews
and the South  African Astronomical Observatory.

The SuperWASP North and South  instruments were constructed and operated with
funds made available from  Consortium Universities and the UK Particle
Physics and Astronomy Research  Council. SuperWASP-North is located in the 
Spanish Roque de Los Muchachos  Observatory on La Palma, Canary Islands which 
is operated by the Instituto de  Astrofisica de Canarias (IAC).

The SOPHIE spectrograph was  constructed with funds from INSU (France) and
the region "Provence Alpes Cotes  d'Azur" (PACA). Contributions were provided
by the Geneva  Observatory.


The SuperWASP telescope:

Artist's impression of a  'hot Jupiter' during  tran sit:
Copyright: Mark A.  Garlick. This image may be freely used to illustrate this
story subject to  copyright accreditation being given to Mark A. Garlick /


Pictures of the SuperWASP  facility and some of its astronomical  images:

The Isaac Newton Group of  Telescopes (ING):

The SOPHIE  spectrograph at Observatoire de Haute  Provence:

The  Royal Astronomical Society (RAS):

The  Particle Physics and Astronomy Research Council (PPARC):


Prof.  Andrew Collier Cameron
School of Physics and Astronomy,
University of St.  Andrews,
St. Andrews,
Fife, KY16 9SS, Scotland
Tel: +44 (0)1334  463147
Mobile: +44 (0)7788 155 986
Fax: +44 (0)1334 463104

Dr. Don Pollacco
Astrophysics Research Centre, 
Main Physics Building,
School of Mathematics & Physics,
Queen's  University,
University Road,
Belfast, BT7 1NN, UK.
Tel: +44 (0)28 9097  3512
Mobile: +44 (0)7788 992 294
Fax. +44 (0)28 9097 3110

Dr. Francois Bouchy
Institut  d'Astrophysique de Paris
98bis Bd Arago
75014 Paris
Tel: +33  1 44 32 80 79
Fax: +33 1 44 32 80 01