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]

1999 HD 209458 PEG 7.65 0.017 2.98 3.522004 TrES-1 LYR 11.79 0.026 2.45 3.032005 HD 149026 HER 8.15 0.003 3.20 2.882005 HD 189733 VUL 7.67 0.025 1.74 2.222006 HAT-P-1 LAC 10.4? 0.016 2.70 4.472006 TrES-2 DRA 11.41 0.017 1.70 2.472006 WASP-1 AND 11.79 0.011 1.40 2.522006 WASP-2 AND 11.98 0.020 1.78 2.152006 XO-1 CrB 11.19 0.023 2.96 3.942007 GJ486 10.68 0.008 0.80 2.642007 HAT-P-2 HER 8.71 0.006 3.46 5.632007 HAT-P-3 UMa 11.86 0.014 2.10 2.902007 TrES-3 HER 12.4? 0.026 1.34 1.312007 XO-2 LYN 11.18 0.015 2.70 2.622007 XO-3 9.80 0.009 2.70 3.19

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 ]

My Own Equipment & SetupMy Own Equipment & Setup

Meade 8” LX200 Meade 8” LX200

Goto TelescopeGoto Telescope

ST-7e ST-7e

CCD CameraCCD CameraEquatorial Equatorial WedgeWedge

PermanentPermanentPier Pier

2005 Attempt – HD 2005 Attempt – HD 209458 209458

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

Weather forecasts / Jet Stream monitoringWeather forecasts / Jet Stream monitoring

Screening Transit Screening Transit OpportunitiesOpportunities

Screening Transit Screening Transit OpportunitiesOpportunities

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00

Time (UT)

Air

ma

ss

Sunset/Sunrise

Civil Dusk/Dawn

Astron. Dusk/Dawn

Naut Dusk/Dawn

HD 209458

Egress

Transit

Ingress

2007-09-26 HD 209458

HD 189733 – good HD 189733 – good candidatecandidate

in Vulpecula in Vulpecula mag +7.67, transit depth 0.025 magmag +7.67, transit depth 0.025 magref star mag +8.1ref star mag +8.1

Results from guiding Results from guiding between framesbetween frames

Practice Photometry Practice Photometry (non exoplanet star)(non exoplanet star)

WeatherWeatherTotal Cloud Cover on Total Cloud Cover on

Sun Sept 2Sun Sept 2ndnd, 23:00 , 23:00 (on the day forecast)(on the day forecast)

Total Cloud Cover ForecastTotal Cloud Cover Forecast

for Sun Sept 2for Sun Sept 2ndnd, 23:00, 23:00

(2 ½ days prior)(2 ½ days prior)

Latest Attempt : WASP-1Latest Attempt : WASP-1

Transit Depth of magnitude Transit Depth of magnitude dip being looked for (0.011 m)dip being looked for (0.011 m)

Pointing Accuracy during Pointing Accuracy during WASP-1 Transit Attempt, WASP-1 Transit Attempt,

2007-09-142007-09-14

How close ?How close ?

Star Mag Transit Depth

Precision needed

SN needed

Attempt Exposure SN achieved

Potential Min RMS

RMS in Practice

(mag) (assume min 50% of transit depth)

(assuming error=1/SNR)

(sec, filter) (min of Var & Comp Star)

HD 209458 7.65 0.017 0.009 120 2005-08-08 15s, V 220 0.005 0.01-0.02

TrES-1 11.79 0.026 0.013 80 2006-08-08 60s, V 80 0.013 ~ 0.01 - 0.02

WASP-1 11.79 0.011 0.006 180 2007-09-14 60s, R 90 0.011 0.009-0.014

HD 189733 7.67 0.025 0.013 80 10s, V 160 0.006 no data

HD 209458 opportunity, 2007-HD 209458 opportunity, 2007-11-1811-18

HD 189733 opportunity, 2007-HD 189733 opportunity, 2007-10-1610-16