Exoplanet Detection with an Exoplanet Detection with an 8” LX200 : 8” LX200 : Part 1 : Preparation Part 1 : Preparation David Richards David Richards 2007-October 2007-October All pictures in this All pictures in this presentation are presentation are by the author (unless by the author (unless specifically indicated) specifically indicated) and were taken with 8” LX200 and were taken with 8” LX200 The Aim The Aim Position Now Position Now UT Hours UT Hours Flux (or Mag) Flux (or Mag) Ingress Ingress Egress Egress Mid Transit Mid Transit Light from Host Star Light from Host Star Light from Control Star Light from Control Star
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Exoplanet Detection with an 8 LX200 : Part 1 : Preparation David Richards 2007-October All pictures in this presentation are by the author (unless specifically.
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Exoplanet Detection with an 8” Exoplanet Detection with an 8” LX200 :LX200 :
Part 1 : PreparationPart 1 : Preparation
David Richards David Richards 2007-October2007-October
All pictures in this presentation All pictures in this presentation are are by the author (unless specifically by the author (unless specifically indicated)indicated)and were taken with 8” LX200 / and were taken with 8” LX200 / ST7eST7e
The AimThe Aim Position NowPosition Now
UT HoursUT HoursF
lux
(or
Mag
)F
lux
(or
Mag
)
IngressIngress EgressEgressMid TransitMid Transit
Light from Host StarLight from Host Star
Light from Control StarLight from Control Star
Exoplanet ChallengeExoplanet Challenge First exoplanet transit detection made in 1999 - HD 209458b First exoplanet transit detection made in 1999 - HD 209458b
HD 209458 (Osiris, 13 Pegasi ) HD 209458 (Osiris, 13 Pegasi ) Charbonneau et al 2000, Henry et al 2000 (from Hipparcos Images ?)Charbonneau et al 2000, Henry et al 2000 (from Hipparcos Images ?)
Castellano et al (NASA Ames) demonstrated HD 209458b transit Castellano et al (NASA Ames) demonstrated HD 209458b transit detection detection with an 8” LX200 telescope and ST7e CCD camerawith an 8” LX200 telescope and ST7e CCD camera
JAAVSO, Vol 33, No 1, 2004JAAVSO, Vol 33, No 1, 2004 Same equipment as me ! Same equipment as me ! Same journal volume as a paper by D.Mais and myself on Mira variables !Same journal volume as a paper by D.Mais and myself on Mira variables ! Led to a strong ambition to detect an Exoplanet for myselfLed to a strong ambition to detect an Exoplanet for myself
14 more transiting exoplanets discovered 2004-200714 more transiting exoplanets discovered 2004-2007 It’s both feasible and now regularly proven that amateurs with CCD It’s both feasible and now regularly proven that amateurs with CCD
cameras and just moderately sized telescopes can detect transit eventscameras and just moderately sized telescopes can detect transit events I’ve made my own exoplanet detection attempts in 2005 and 2006, I’ve made my own exoplanet detection attempts in 2005 and 2006,
but without firm successbut without firm success Requires ideal sky conditions and the highest possible precision (<0.005 Requires ideal sky conditions and the highest possible precision (<0.005
m)m) I’m currently optimising my imaging setup and (with luck) hope to I’m currently optimising my imaging setup and (with luck) hope to
make a firm transit detection during the 2007/8 season.make a firm transit detection during the 2007/8 season.
Table of Nearby Transiting Table of Nearby Transiting Exoplanets (Jul 2007)Exoplanets (Jul 2007)
Discovery Object Constellation V Depth Length PeriodDate Name Mag [mag] [hr] [day]
Note : Most known transiting exoplanet sols are visible Note : Most known transiting exoplanet sols are visible from N. Hemisphere )from N. Hemisphere )5 distant exoplanets (OGLE-TR-10,56,111,113,132) in Sagittarius and 5 distant exoplanets (OGLE-TR-10,56,111,113,132) in Sagittarius and
Carina are not listed, Carina are not listed, [OGLE - Optical Gravitional Lensing Experiment ][OGLE - Optical Gravitional Lensing Experiment ]
Planet HD 209458b around HD 209458 (Osiris) Planet HD 209458b around HD 209458 (Osiris) Discovered in 1999 (followed up 1999-2004)Discovered in 1999 (followed up 1999-2004)Parent Sol is a +7.6 magnitude star in PegasusParent Sol is a +7.6 magnitude star in PegasusOrbital period 3.52 days. Transit duration ~ 3 hours,Orbital period 3.52 days. Transit duration ~ 3 hours,Transit depth 0.0165 magTransit depth 0.0165 mag
Depth of magnitude Depth of magnitude dip being looked fordip being looked for
60s exp (C Filter)
Attempted Transit Observation in V Filters, 2005-08-08Attempted Transit Observation in V Filters, 2005-08-08
15s exposures
(V Filter)
2006 Attempt – TrES-12006 Attempt – TrES-1
End Transit(predicted)
Mid Transit(predicted)
Planet TrES-1 around GSC 2652:1324 Planet TrES-1 around GSC 2652:1324 Jupiter sized planet discovered in 2003-2004 (R.Alonso et al)Jupiter sized planet discovered in 2003-2004 (R.Alonso et al)Sol +11.8 magnitude star in Lyra (lying at ~ 500 ly distance)Sol +11.8 magnitude star in Lyra (lying at ~ 500 ly distance)Orbital period 3.03 days. Transit duration ~ 2.5 hours,Orbital period 3.03 days. Transit duration ~ 2.5 hours,Transit depth 0.023 magTransit depth 0.023 mag
Depth of magnitude Depth of magnitude dip being looked fordip being looked for
30s exposures
(C Filter)
Av 3 x 20s exp (C Filter)
Attempted Transit Observation in C Filters, 2006-08-08 / 09Attempted Transit Observation in C Filters, 2006-08-08 / 09
Improving my chancesImproving my chances Transit Opportunities - Dates/Times /AirmassTransit Opportunities - Dates/Times /Airmass
Screening worksheet/chartsScreening worksheet/charts Baseline Images for each candidateBaseline Images for each candidate
Central Image Positions, Reference Stars, Exposure TimesCentral Image Positions, Reference Stars, Exposure Times Better Flat fieldsBetter Flat fields
Not realistically feasible with current focuser, due to gravity droop on CCD cameraNot realistically feasible with current focuser, due to gravity droop on CCD camera(option to invest in new heavy duty focuser, but avoiding at this stage)(option to invest in new heavy duty focuser, but avoiding at this stage)
Anti-Dew SystemAnti-Dew System New power source installed in early 2007 has fixed previous problem with dew New power source installed in early 2007 has fixed previous problem with dew
heaterheater Reduction in star drift / keep stars fixed on same pixelsReduction in star drift / keep stars fixed on same pixels
Improved Polar Alignment (aiming for less than 1 arc min, current misalignment is Improved Polar Alignment (aiming for less than 1 arc min, current misalignment is 3.4 arc min )3.4 arc min )
Guiding between frames with new script that is robust to passing cloudGuiding between frames with new script that is robust to passing cloud Robust Software / ProceduresRobust Software / Procedures
Software that’s going to work on that one ideal night when conditions are perfectSoftware that’s going to work on that one ideal night when conditions are perfect Focus / FWHM monitoringFocus / FWHM monitoring
Script to monitor FWHM / sky brightness in realtimeScript to monitor FWHM / sky brightness in realtime Better prediction of Clear Weather & Good SeeingBetter prediction of Clear Weather & Good Seeing