Photometric follow-up of transiting planet candidates

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Photometric follow-up of transiting planet
candidates
Marton Hidas UNSW
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Transit searches

• Periodic drop in flux as planet transits host
  star
• Low probability of observing transit
• need many stars (10000)
• Prefer bright stars (Vlt13)
• wide-field (few degrees)

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Wide-field transit searches

• Wide-field searches target hot Jupiters around
  F-M dwarfs
• about 1 in 1000 stars has one in edge-on orbit
• period a few days
• transit depth 0.01 mag
• transit duration 3 hours

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Wide-field transit searches

• One drawback
• most have 10 pixels
• AND
• look at crowded fields
• Blending
• Deeper eclipses become planet-like

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Photometric follow-up

• Resolve blended stars
• Identify star with transits measure actual
  depth
• Two colours
• Remove eclipsing binaries
• Obtain higher precision lightcurve
• Can be fitted with model to obtain parameters of
  system

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Photometric follow-up with PILOT

• Advantages
• High spatial resolution
• Continuous time coverage
• Low scintillation small variation in airmass
• high-precision photometry
• Targets are bright
• can be used as AO reference stars

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Photometric follow-up with PILOT

• Follow-up in V R, or V I
• At shortest wavenengths, isoplanatic angle is
  10
• PSF will vary significantly within region of
  interest (60), and with time!
• difficult to obtain high photometric precision
• Possible solutions
• Use only tip-tilt correction
• Use V for highest resolution, photometry in R, I
  (J?)
• PSF must be well sampled

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Three-transit phase coverage
D. Caldwell
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South Pole Extrasolar Planet Search
D. Caldwell