Photometric Transits from the MACHO Project Database

Drake, A. J.; Cook, K. H.

doi:10.1086/381868

Cited by 40 publications

(24 citation statements)

References 34 publications

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“…Blending, grazing Based on observations collected at the European Southern Observatory, La Silla, Chile, within the Observing Programme 70.B-0547(B). eclipses, and contamination by giant stars, among other problems, make some detections somewhat ambiguous (Dreizler et al 2002;Brown et al 2001;Drake 2003;Drake & Cook 2004). Clearly transit surveys have the ability to discover many interesting exoplanet candidates, but non-planetary events must be filtered out.…”

Section: Introductionmentioning

confidence: 99%

Characterisation of extrasolar planetary transit candidates

Minniti¹,

Valls–Gabaud

Rejkuba

2005

A&A

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Abstract. The detection of transits is an efficient technique to uncover faint companions around stars. The full characterisation of the companions (M-type stars, brown dwarfs or exoplanets) requires high-resolution spectroscopy to measure properly masses and radii. With the advent of massive variability surveys over wide fields, the large number of possible candidates makes such a full characterisation for all of them impractical. We explore here a fast technique to pre-select the most promising candidates using either near-IR photometry or low resolution spectroscopy. We develop a new method based on the well-calibrated surface brightness relation along with the correlation between mass and luminosity for main sequence stars, so that not only can giant stars be excluded but also accurate effective temperatures and radii measured. The main source of uncertainty arises from the unknown dispersion of extinction at a given distance. We apply this technique to our observations of a sample of 34 stars extracted from the 62 low-depth transits identified by OGLE during their survey of some 10 5 stars in the Carina fields of the Galactic disc. We infer that at least 78% of the companions of the stars which are well characterised in this sample are not exoplanets. Stars OGLE-TR-105, OGLE-TR-109 and OGLE-TR-111 are the likeliest to host exoplanets and deserve high-resolution follow-up studies. Most recently, OGLE-TR-111 was confirmed as an exoplanet with M planet 0.53 ± 0.11 M Jup , confirming the efficiency of our method in pre-selecting reliable planetary transit candidates.

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Section: Introductionmentioning

confidence: 99%

Characterisation of extrasolar planetary transit candidates

Minniti¹,

Valls–Gabaud

Rejkuba

2005

A&A

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“…The inclination of the orbital plane and the third light contribution (bottom three plots) and the radius R 2 (top two plots) of the potential transiting objects were treated to vary. A list of the orbital parameters P MACHO (period given by Drake & Cook 2004), the derived period P in our analyses, the RV amplitude K, the system velocity V 0 , the orbital inclination i, and in cases of systems with elliptical orbits, e the eccentricity and ω the longitude of the periastron as well as the mass, effective temperature, and radius is shown in Table 1.…”

Section: Resultsmentioning

confidence: 99%

“…4. Drake & Cook (2004) and P denotes the period derived using the light-curves and RV measurements. K is the semi-amplitude of the RV variations, V 0 the system velocity, and i the orbital inclination.…”

Section: Introductionmentioning

confidence: 99%

Investigation of transit-selected exoplanet candidates from the MACHO survey

Hügelmeyer

Homeier

Reiners

2007

A&A

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Context. Planets outside our solar system transiting their host star, i.e. those with an orbital inclination near 90• , are of special interest to derive physical properties of extrasolar planets. With the knowledge of the host star's physical parameters, the planetary radius can be determined. Combined with spectroscopic observations the mass and therefore the density can be derived from Dopplermeasurements. Depending on the brightness of the host star, additional information, e.g. about the spin-orbit alignment between the host star and planetary orbit, can be obtained. Aims. The last few years have witnessed a growing success of transit surveys. Among other surveys, the MACHO project provided nine potential transiting planets, several of them with relatively bright parent stars. The photometric signature of a transit event is, however, insufficient to confirm the planetary nature of the faint companion. The aim of this paper therefore is a determination of the spectroscopic parameters of the host stars as well as a dynamical mass determination through Doppler-measurements. Methods. We obtained follow-up high-resolution spectra for five stars selected from the MACHO sample, which are consistent with transits of low-luminosity objects. Radial velocities were determined by means of cross-correlation with model spectra. The MACHO light-curves were compared to simulations based on the physical parameters of the system derived from the radial velocities and spectral analyses. Results. We show that all transit light-curves of the exoplanet candidates analysed in this work can be explained by eclipses of stellar objects, hence none of the five transiting objects is a planet.

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“…undiluted) transit depth measured. Secondly, the host star's colours yield estimates of its size and mass, and thus constrain models of the transiting system (Drake & Cook 2004). Many binary systems can be identified by the colour dependence of the eclipse shape, even when diluted (Tingley 2004).…”

Section: Imaging and Photometric Follow-up Of Transiting Planet Candimentioning

confidence: 99%

Science Programs for a 2-m Class Telescope at Dome C, Antarctica: PILOT, the Pathfinder for an International Large Optical Telescope

Burton

Lawrence

Ashley

et al. 2005

Publ. – Astron. Soc. Aust

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Abstract:The cold, dry, and stable air above the summits of the Antarctic plateau provides the best groundbased observing conditions from optical to sub-millimetre wavelengths to be found on the Earth. Pathfinder for an International Large Optical Telescope (PILOT) is a proposed 2 m telescope, to be built at Dome C in Antarctica, able to exploit these conditions for conducting astronomy at optical and infrared wavelengths. While PILOT is intended as a pathfinder towards the construction of future grand-design facilities, it will also be able to undertake a range of fundamental science investigations in its own right. This paper provides the performance specifications for PILOT, including its instrumentation. It then describes the kinds of projects that it could best conduct. These range from planetary science to the search for other solar systems, from star formation within the Galaxy to the star formation history of the Universe, and from gravitational lensing caused by exo-planets to that produced by the cosmic web of dark matter. PILOT would be particularly powerful for wide-field imaging at infrared wavelengths, achieving near diffraction-limited performance with simple tip-tilt wavefront correction. PILOT would also be capable of near diffraction-limited performance in the optical wavebands, as well be able to open new wavebands for regular ground-based observation, in the mid-IR from 17 to 40 µm and in the sub-millimetre at 200 µm.

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Photometric Transits from the MACHO Project Database

Cited by 40 publications

References 34 publications

Characterisation of extrasolar planetary transit candidates

Characterisation of extrasolar planetary transit candidates

Investigation of transit-selected exoplanet candidates from the MACHO survey

Science Programs for a 2-m Class Telescope at Dome C, Antarctica: PILOT, the Pathfinder for an International Large Optical Telescope

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