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©Hans Deeg, Nice 05/2004 PASS – a Permanent All Sky Survey for the Detection of Transiting Planets an instrument capable to perform a permanent photometric.

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Presentation on theme: "©Hans Deeg, Nice 05/2004 PASS – a Permanent All Sky Survey for the Detection of Transiting Planets an instrument capable to perform a permanent photometric."— Presentation transcript:

1 ©Hans Deeg, Nice 05/2004 PASS – a Permanent All Sky Survey for the Detection of Transiting Planets an instrument capable to perform a permanent photometric survey of the entire (visible) sky principal objective: detection of all giant planets that are transiting bright stars many additional objectives can be realized -Detection/study of variable phenomena of all kinds prototype of PASS at Obs. Teide, Tenerife possiblities for collaborations - placement on Dome C ? Hans J. Deeg 1, Roi Alonso 1, Juan Antonio Belmonte 1, Khalid Alsubai 2, Laurance Doyle 3 1 Instituto de Astrofísica de Canarias, Spain, 2 Univ of St Andrews, Great Britain, 3 SETI Institute, USA

2 ©Hans Deeg, Nice 05/2004 Limitations of radial velocity detection: mass unknown by sin i ; i = inclination, beyond orbital parameters, no further info can be gained from planet mass limit > 10 M Earth at 1 AU (1m/s) Transit method is the only technique in use to detect Planets on which ‘deeper’ investigations can be made Earth-size planets in near future First success in 1999: (Charbonneau et al., Henry et al.), HD209458b transit. From many follow-up studies, it is today by far best known planet : Several transit candidates from OGLE project, 3 confirmed Current status of exoplanet searches: >100 Planets (and several planetary systems) discovered, most by radial velocities.

3 ©Hans Deeg, Nice 05/2004 Giant planet transits (gif anim) Data: Deeg&Garrido, 26 Jul m Sierra Nevada Telescope Example: transit of planet of HD typical requirements for ground based searches: detect brightness variation: 0.5-2%, lasting a few hours at least 3 transits should be observed for planetary periods of days to weeks.

4 ©Hans Deeg, Nice 05/2004 a Probability of Transit being observable  The fraction of sky where a transit can be observed from. P tr = (R * +R pl )/a Earth-Sun: 0.5% Venus-Sun: 0.7% Jupiter-Sun: 0.1% Hot Giant planet: 5-10% a Zone where transit can be seen from Solutions: Observe 1000´s of stars simultaneously (wide field CCD cameras) or stars with preferential alignement: Eclipsing Binaries TEP project (M4.5 eclipsing binary) Nearly all transit projects

5 ©Hans Deeg, Nice 05/2004 Detection of giant planet transits of all stars, with a magnitude limit of V ~ Surveying about stars in one hemisphere, in entire sky ~60 planets may be detected in one hemisphere, 100 in total. This will give the best sample of planets for follow-up studies: detects star-planet systems with highest brightness (=signal), typically nearby ones. follow-up measurements need highest possible S/N for scientific advances (i.e. spectroscopy of atmosphere, multi-color photometry). transiting planets detected by PASS will provide an optimum sample for a variety of research (using larger ground based or space based instruments) to gain a deeper insight into the formation and current physical status of giant planets and their atmospheres. Main-Objective of PASS:

6 ©Hans Deeg, Nice 05/2004 EW S N Local Sky view 28.5°N current working hypothesis: 15 cameras on fixed mount f=50mm, 1k x 1k or 2k x 2k CCDs 28°x28° field of view (50 or 100”/pix) complete coverage for altitudes > 34° coverage  > –17.5° from Tenerife full sky coverage with 2nd instrument in South horizon dashed line: 30°alt The Instrument

7 ©Hans Deeg, Nice 05/2004 PASS would perform real-time all-sky observations for transit detection. planet transit detection experiments real-time all-sky-observations PASS telescopes with guiding: surveying small zones in sky fish-eye lenses: for meterological surveys, observing site quality, meteorite detection The context of other experiments:

8 ©Hans Deeg, Nice 05/2004 Transit detection experiments Horne 2003 the idea for PASS doesn’t come out of the air but from: ‘Treasure’ a proposal to ESA for all-sky transit search with 36 small telescopes in fly-eye configuration, by Jean Schneider Doug Caldwell’s (NASA-Ames) camera at the S-Pole (scanning small zone around celestial S-Pole with fixed f=180mm lens)

9 ©Hans Deeg, Nice 05/2004 Fish eye Cameras (CONCAM, TASCA, and many individual expermients) Intention: survey sky- brightness and extinction, meteorites relative measure of star- brightness, range mag, is precise to 1-2% not suitable for transit detection; too few sample stars Federico de la Paz, OPC-IAC

10 ©Hans Deeg, Nice 05/2004 Anxilliary Objectives of PASS: Detection of any temporal astronomical phenomena: Detection and follow-up of stellar variabilities with low amplitudes (up to 0.1%, depending on stellar brightness and frequency) -variable stars of any kind -flares Detection of supernovae Recording of frequency and direction of meteorites Detection of optical counterparts to gamma ray bursts and ‘optical flashes’ Detection of asteroids, comets, stellar occultations (e.g. by Kuiper-belt objects) Sky-quality and meteorological statistics: Recording of sky brightness and extinction in all directions Percentage of clear sky, clouds Detection of satellites and airplanes (intrusions into protected sky area over observatory) long-term follow-up of eclipsing binary minimum times is another method to detect planets

11 ©Hans Deeg, Nice 05/2004 The PASS Instrument Features : permanent survey of entire visible sky is only possible with a fixed instrumment mechanical simplicity, low maintenance Stars will trail over exactly the same pixels every night at the same sidereal time: no guiding or flatfielding errors, high stability and repeatability. brightness-behaviour of each star can be compared across many nights and against many other stars. Long duration of observations allows calibration for different meteorological conditions (eg. extinction, temperature). Seeing is not important. N 1m Working hypothesis: 15 Cameras on a common fixed mount. f=50mm lenses, 28°x28°f.o.v. CCD detectors with about 25x25mm size (1k x 1k CCD: scale of 100”/pix.) drawn with 10 cameras only

12 ©Hans Deeg, Nice 05/2004 Yearly observational coverage (instruments in N and S) Assumptions: -one site at 30ºN -one site at 35ºS - complete sky above 30º altitude is observed hrs/yr of clear sky blue line: coverage from N violet line: coverage from S green line: summed coverage (night-hours may not overlap in N and S) with sites in Europe and (Chile or Australia, Antarctica): -> fairly uniform coverage over entire declination range Expected number of hours that a star at a given declination can be observed in one year

13 ©Hans Deeg, Nice 05/2004 Dome C yearly observational coverage Assumptions: -one site at 30ºN -Dome C at 75ºS - complete sky above 15º in Dome C hrs/yr in Dome C hrs/yr in N blue line: coverage from N violet line: coverage from S green line: summed coverage Expected number of hours that a star at a given declination can be observed in one year

14 ©Hans Deeg, Nice 05/2004 Probability to observe multiple transits To confirm a transit-like feature as potential planet, it needs to be observed at least 3 times. What is the probability P obs to observe so many transits, if the transits are detectable with the instrument? Depends on planet period and T obs 1 season: T obs = 400h for 1 array, 650h for 2 arr. 3 seasons: T obs = 1200 h for 1 array, 2050h for 2 arr 1-2 seasons give access to ‘hot-giant’ planets several seasons, preferably multiple locations, for moderate-temperature planets (there are several experiments under way intending to detect transits with T obs ~O(100hrs). It won’t work.) 650h 400h 2050h 1200h Note: for circumpolar stars on Dome C, coverage in 1 season corresponds to 4-5 seasons observing non-cicumpolar stars at moderate-latitude site (~2000 hrs)

15 ©Hans Deeg, Nice 05/2004 Approach of feasability study 1. Theoretical S/N calculations 2. Photometry on artificial images with all known noise characteristics 3. Photometry on real images under controlled conditions agrees well TBD financed by Span. Plan Nacional Astronomía y Astrofísica

16 ©Hans Deeg, Nice 05/2004 S/N calculations S/N from photometry on simulated images, t exp =20s 90 x90 pix, 2.5° x 2.5° 10° gal. lat. Curve is Total S/N in 20 sec from left gaph Limit for transit detc: rms ~3.5mmag in 900sec PASS - Baseline : CCD KAF1001 (1k x1k) 50mm, f/2.0, t exp =20sec, obsv. site: alt=2400m, no moon, 1.4 airmass

17 ©Hans Deeg, Nice 05/2004 Simulated observations Left: simulated PASS star field for an exposure of 60 seconds. The size of the field is about 2 x 2 degree. The brightest star is of 4th mag, several have 6-7 mag, and the faintest ones are mag. The red boxes over the brightest stars shows how the aperture mask is being build up, starting with the brightest stars. Right: final aperture mask, where the maximum number of non-overlapping traces have been fitted in. typ star density at b=10°  =0°, t exp =60sec, 20sec phot. noise for stars and backgrd (moon) psf expected for 50mm lens simulation of CCD-QE with inter-pixel resolution

18 ©Hans Deeg, Nice 05/2004 performance variations against baseline variations to mag-limit: dec=45°: +0.1 dec=75°: +0.6 quarter moon: /4 moon: -0.8 full moon: -1.3 airmass 1.0: +0.1 airmass 1.7: -0.1 airmass 2.0: +0.3 CCD with double res (2k x2k): +0.2 back-illum (high-QE) CCD: +0.2 PASS - Baseline : CCD KAF1001 (1k x1k), with max. QE of mm, f/2.0, t exp =20sec, obsv. site: alt=2400m, no moon 1.4 airmasses -> limit for transit detection ~10.5 mag (0.0 with Thx 7899, lower QE)

19 ©Hans Deeg, Nice 05/2004 Baseline vs Dome-C Baseline: (typ. good observing site) seeing for 2400m altitude, sky-brightness mag scintillation dominates < 10mag photon noise dominates ~10mag sky noise dominates >10.5 mag The instrument is optimized near the faint end of sample range. Dome C: scintillation assumed as 1/4 of BL sky-brightness 22 mag scintillation dominates < 7mag photon noise dominates mag The instrument is optimized over the entire sample range Also a small gain of 0.3mag in transit detc. limit from darker sky Baseline Dome C

20 ©Hans Deeg, Nice 05/2004 The PASS prototype Started this year with funding by Span. Science Ministry. (Pl. Nac. AYA ) cameras; currently a loaned AP10, 2k x 2k Thomson CCD, further one will be obtained soon. - lenses Nikon 50mm/1.2, 50/1.4 - fixed mount with adjustable tripode head. -Sequences of a few hours have been taken, analysis in progress -Construction of dome in progress -Potential placement at DomeC no moving part with Kodak KAI series interline CCD ‘First light’ 16 Jan 04 with AP10 (2k x2k) camera loaned by Univ. St.Andrews (K. Horne)

21 ©Hans Deeg, Nice 05/2004 Objectives of PASS prototype get observational data for feasibility study of PASS concept detailed characterization of instrument in its capability to detect planets (’discovery space’) development of photometry software comparison with simulated data study about possible additional objectives define specifications for a final instrument start of planet survey with 2– camera system

22 ©Hans Deeg, Nice 05/2004 PASS0 image texp=60sec, f/2.0 (f=50mm) stars to ~11 mag can be identified visually seq. of 20 sec exposures taken in first night

23 ©Hans Deeg, Nice 05/2004 Data analysis organization CCD(s) first-order image-processing extract raw photometry make ‘superimages’ (each h, d, week) or depending on params like temp., extinction search for uncatalogized, new, temporary objects (compare super-ims to indiv. ones) calibrated photometry search transits, stellar variability follow-up known variables meteo- rology... asteroids comets meteorites  -ray burst SN save images? TBD yellow: ‘science analysis’ pipelines white: ‘data-product’ pipelines CCD(s)

24 ©Hans Deeg, Nice 05/2004 Collaborations are seeked... real time pipeline processing among several computers everything related with databases definition of stellar sample (all-sky study on MS fraction; stellar types) classification / interpretation of variables’ lightcurves any kind of study towards definition of auxiliary objectives follow-up/verification observations of candidates (transits and variables/aux. objectives)

25 ©Hans Deeg, Nice 05/2004 Conclusions An instrument with a novel design for planetary transit detection is being developed Primary goal is detection of ALL giant-planet transits around bright (nearby) stars Ample range of auxilliary objectives Realization of these objectives needs a variety of expertise and development of analysis modules, opportunities for participation Observations with prototypes : -detailed characterization of instrument capabilities -verification of achievability of objectives (‘detection-space’) will result Interested in collaborations more info in paper accepted for PASPwww.iac.es/proyectos/pass

26 ©Hans Deeg, Nice 05/2004 Conclusions for Concordia Placement Significantly enhanced photometric performance Most (=circumpolar) stars will receive coverage in 12 season that corresponds to 4-5 years of observing in moderate-latitude sites instrument design should be well adaptable to setting in extreme cold and requiring little maintenance: -no moving parts beyond camera-shutter -camera shutter might be avoided employing frame-transfer CCD chips (needs study)

27 ©Hans Deeg, Nice 05/2004 There is always the potential for unexpected discoveries! Fish-eye image from TASCA experiment (Chile)

28 ©Hans Deeg, Nice 05/2004 fin de la presentación

29 ©Hans Deeg, Nice 05/2004 XVI Canary Islands Winterschool ‘Extrasolar Planets’ Teachers: Stephane Udry (Obsv. Genève)Properties of extrasolar planets Tim Brown (HAO)Characterizing extrasolar planets Laurance Doyle (SETI)Planet detection projects and methods Rafael Rebolo (IAC) From planets to brown dwarfs to stars Günther Wuchterl (MPE)From clouds to planet systems (formation and evolution) Agustín Sánchez Lavega (UPV)The solar system in perspective Jim Kasting (Penn St. U.) The potential for life (habitability) Franck SelsisCan life be detected? (biomarkers) Puerto de la Cruz, 22 Nov - 3 Dec 2004 Sci. Organizers: H.J. Deeg, J.A. Belmonte Application deadline: 30 June 2004 more info in (link on meetings)www.iac.es

30 ©Hans Deeg, Nice 05/2004 Giant planet transits (no anim) Data: Deeg&Garrido, 26 Jul m Sierra Nevada Telescope Example: transit of planet of HD typical parameters: brightness variation: 0.5-2% period: days to weeks


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