WASP:Wide Angle Search for extrasolar Planets

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HTN Workshop, Jul 2005
WASPWide Angle Search for extrasolar Planets

Damian J. Christian On behalf of the WASP
Consortium PI -- Dr. Don Pollaco (QUB) Isaac
Newton Group, Institute de Astrofisica Canaries,
University of St Andrews, University of
Leicester, University of Keele, Cambridge
University, The Open University, Queens
University Belfast

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• Brief Outline
• Brief history and methods for finding Extra-solar
  planets
• History/Instrument development for SuperWASP
• SuperWASP
• Construction
• Sample images
• Data Reduction
• Sample Light Curves
• The Future

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Extra-Solar Planets History

• 1992 First exo-planets discovered around a
  pulsar.
• --only Earth sized planets
  known.
• 1994 Mayor and Queloz discover planet orbiting
  51 Peg
• 1995 present Radial-velocity surveys with large
  telescopes continue to find ESP (150 and
  counting)
• 13 Multiple Planet systems, 2 Neptume mass, 1
  with 7 MEARTH
• These show an unexpected population of large
  Jupiter sized planets in short period orbits
  (days, weeks).
• Relative sizes, eg Jupiter 0.1 x diameter of sun,
  expected drop in brightness 1
• New OGLE very hot-Jupiters (P 1-2 days)

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Methods for finding Extra-solar planets

• Pulsar Timing
• small anomalies in the timing of pulsars can
  betray the Planets with masses on order of the
  Earth's or greater can be detected.
• first earth-mass extrasolar planets confirmed
  were found in 1992
• Astrometry wobble on the sky
• Gravitational Lensing enchance starlight
• Direct Imaging
• Radial Velocities Doppler Wobble (gt 150 ESP)
• Photometric Transits

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Planet Transit detection
3 - 4 hrs
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• Planet Transits
• 20 of Radial Velocity surveys
• P4 days, a0.05 AU
• Hot Jupiter
• ? 1 drop in intensity
• Factors leading to detection
• orbital inclination 10 should transit
• Depth of transit (Rp/R)2
• ? deeper transits for later-type stars
• Recent estimates 1 to 10 planets per 20,000
  stars
• (Horne 2002 Brown 2003)

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Project HistoryThe original Cocam - 1996

• Comet Hyakutake 1996B2 publicity images at ING
• EEV1280x2220 thick detector read out within
  observatory infra-structure
• Usable FOV 30x40 degrees!
• Nightmare!

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The next development Cocam2

• Built for observatory publicity images of Comet
  Hale Bopp
• Same detector, now uses Pentax 180mm f2.8 medium
  format optics

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Cocam2 Discovery of the Sodium tail
Very inexpensive publication on observational
astronomy (Cremonese et al.1997)
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Cocam2 further development

• Upgrade of detector to 2048x2048 SITe2 chip
• FOV 10x10 degrees, little vigneting
• Slightly de-focussed, instrument produces
  accurate photometry

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Transits of exo-planets

• First transit detected by Charbonneau et al
  (1999) HD209458b

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WASP0 Technology Demonstrator

• Wide Angle Search for Planets prototype camera,
  total cost about 15K produced gt1GB/night
• Everything commercially available e.g. detector
  Apogee 2048x2048 14-bit.
• Operated for 3 months in La Palma and 6 months
  in Greece

Funded between QUB/STA
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WASP0 technology demonstrator

• Observations of HD209458 on one night.
• 1 photometry feasible with this equipment.

Kane et al. 2004
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Design Performance and science areas

• 1 photometry down to V12 mag,
• Extra-solar Planets
• Near Earth Objects
• Variable stars of all sorts, including SN and
  novae
• Optical Transients (gamma-ray bursts)

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SuperWASP Design Philosophy

• Obtain imaging of as wide a field as possible.
• Purchase all components off-the-shelf .
• All functions to be potentially robotic
  (including enclosure, mount, data taking and data
  backup) .

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Mount

• Provided by Optical Mechanics Inc. (OMI).
• Pointing accuracy 30 arcsec
• Operated via Talon control software under Linux

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Cameras

• Optics Canon 200mm f/1.8 lens for each detector.
  
• Detectors e2v42 2048x2048, thermoelectric cooled,
  
• 16 Bit electronics
• 4 sec readout
• Very low noise characteristics (manufactured by
  Andor Technology, Belfast).
• Each unit has FOV 7.8o x 7.8o (angular scale of
  14 arcsec/pixel.)

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Computing

• 1 PC for Telescope control (TCS)
• Interfaces to GPS, weather, dome
• Red Hat Linux OS for all computing
• 1 PC per camera
• Dell Power Edge 2550
• DAS with customized 32-bit PCI CCD controller
• 1 PC autoloader for tape writing (DLT)
• 8.4 MB/image x 600/night x 8 cameras 40
  GB/night
• Ultrium DLT new this year (200 GB/tape)
• Add 1TB storage array and possible reduction on
  mountain

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Enclosure

• Built by Gendall-Rainford Products (Cornwall)
• Weather station, GPS system, air-conditioning and
  Lightning conductor
• Instrument and computer rooms.
• Normal operations instrument room roof slides
  onto computer room under hydraulic pressure

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SuperWASP La Palma Construction (1)
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SuperWASP
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SuperWASP Construction (2)
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SuperWASP I La Palma

• Commissioned April 2004
• Current 5 Camera set-up
• 8 Cameras for 2005

• Telescope mount
• -rapid slewing (10o/sec)
• -pointing to few arcsec

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Ultra-Wide Field Sample Images
D. Christian (QUB)
(Above) M31 and (right) 5
Camera Image centered in the Galactic Plane (3
sec exposure).
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Ultra-Wide Field Sample Image
Orion (M42) 4 Camera Image (1 sec exposure).
15o
D. Christian (QUB)
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• Currently, SuperWASP is the widest field
  survey
• WHT Wide-Field Survey 0.09 º
• PSST 28.1 º
• STARE 37.2 º
• VULCAN 49 º
• HAT-1 78.1 º

Orion (M42) 4 Camera Image (1 sec exposure).
SuperWASP was 5x61º
SuperWASP will be 8x61º
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Current Observing Strategy

• Concentrating on magnitudes 8--15
• Goal of 1 photometry down to 12th mag
• S/N and allows RV follow-up
• Stare mode
• Fixed RA -starting at RA and step as fnc(LST)
• Choose higher Galactic latitudes (Dec 28)
• -avoid crowded fields/blending
• 8 fields per scan ? 8 minute cadence
• Imaging 3000 sq. deg each night (7 of sky)
• Add in all-sky survey mode

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Data Reduction

• Calibrations
• Biases Darks subtracted
• Flat-fielded with sky flats
• Astrometric Photometric solutions
• (Tycho-2/USNO-B)
• Aperture Photometry
• Post processing
• Public Interface Archive (LEDAS)

4 mmag
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Sample Light Curvesbinaries

• Folded light curves of a new 9th magnitude
  variable (left) and Algol system SZ Her (below).

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Sample Light Curveslow amplitude
Light curve
Light curve
0.05 mag
0.07 mag
Folded light curve (P5.5 d)
Folded light curve (P1.5 d)
Light curves courtesy R. Street (QUB)
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Sample Light Curveslow amplitude
0.2 mag
? 4 days?
0.1 mag
?3 days ?
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Current exo-planets detected by Transits
10b
OGLE-TR-111
TrES-1
Seven!
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The future

• Continue ESP searching (4 TB of data from 2004)
• Install next 3 cameras.
• Add all-sky survey mode
• image all visible sky from site at least once
  per night.
• Robotic operation of SuperWASP.
• Real Time follow-up with Liverpool Telescope (2m)
• A second WASP facility is being built at South
  Africa (SAAO) through the University of Keele.

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http//www.superwasp.org