A Search for Hot Massive Extrasolar Planets around Nearby Young Stars with the Adaptive Optics System NACO

Context. The new planet finder for the Very Large Telescope (VLT), the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE), just had its first light in Paranal. A dedicated instrument for the direct detection of planets, SPHERE, is composed of a polametric camera in visible light, the Zurich IMager POLarimeter (ZIMPOL), and two near-infrared sub-systems: the Infra-Red Dual-beam Imager and Spectrograph (IRDIS), a multi-purpose camera for imaging, polarimetry, and long-slit spectroscopy, and the integral field spectrograph (IFS), an integral field spectrograph. Aims. We present the results obtained from the analysis of data taken during the laboratory integration and validation phase, after the injection of synthetic planets. Since no continuous field rotation could be performed in the laboratory, this analysis presents results obtained using reduction techniques that do not use the angular differential imaging (ADI) technique. Methods. To perform the simulations, we used the instrumental point spread function (PSF) and model spectra of L and T-type objects scaled in contrast with respect to the host star. We evaluated the expected error in astrometry and photometry as a function of the signal to noise of companions, after spectral differential imaging (SDI) reduction for IRDIS and spectral deconvolution (SD) or principal component analysis (PCA) data reductions for IFS. Results. We deduced from our analysis, for example, that β Picb, a 12 Myr old planet of ∼10 M Jup and semi-major axis of 9-10 AU, would be detected with IRDIS with a photometric error of 0.16 mag and with a relative astrometric position error of 1.1 mas. With IFS, we could retrieve a spectrum with error bars of about 0.15 mag on each channel and astrometric relative position error of 0.6 mas. For a fainter object such as HR 8799d, a 13 M Jup planet at a distance of 27 AU, IRDIS could obtain a relative astrometric error of 3 mas.

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“…The procedure (following Masciadri et al 2005) that we have used to calculate the contrast is the following:…”

Section: Data Reduction and Detection Limitsmentioning

confidence: 99%

Performance of the VLT Planet Finder SPHERE

Zurlo

Vigan

Mesa

et al. 2014

A&A

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“…Overall, our binary frequencies of a few percents are in agreement with the number of wide substellar companions to young solar analogues (0.5-6.3% for separations in the 28-1590 au range; Metchev & Hillenbrand 2009), M dwarfs (0.1-2.2% for separations larger than ∼120 au ; Radigan et al 2008), the frequency of 1 ± 1% of brown dwarf companions to GKM stars in the 75-300 au range (McCarthy & Zuckerman 2004) or the lack of planetary-mass objects more massive than 5-10 M Jup around young nearby stars beyond 36-65 au (Masciadri et al 2005). Similarly, Raghavan et al (2010) derived a stellar multiplicity of 7.3% and 2.2% among solar-type stars within 25 pc for projected separations in the 1000-10 000 au and 10 000-50 000 au ranges, respectively (their Fig.…”

Section: Multiplicity Of Planet-host Starsmentioning

confidence: 99%

Binary frequency of planet-host stars at wide separations

Lodieu

Pérez‐Garrido

Béjar

et al. 2014

A&A

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Aims. The aim of the project is to improve our knowledge on the multiplicity of planet-host stars at wide physical separations. Methods. We cross-matched approximately 6200 square degree area of the southern sky imaged by the Visible Infrared Survey Telescope for Astronomy (VISTA) Hemisphere Survey (VHS) with the Two Micron All Sky Survey (2MASS) to look for wide common proper motion companions to known planet-host stars. We complemented our astrometric search with photometric criteria. Results. We confirmed spectroscopically the co-moving nature of seven sources out of 16 companion candidates and discarded eight, while the remaining one stays as a candidate. Among these new wide companions to planet-host stars, we discovered a T4.5 dwarf companion at 6.3 arcmin (∼9000 au) from HIP 70849, a K7V star which hosts a 9 Jupiter mass planet with an eccentric orbit. We also report two new stellar M dwarf companions to one G and one metal-rich K star. We infer stellar and substellar binary frequencies for our complete sample of 37 targets of 5.4 ± 3.8% and 2.7 ± 2.7% (1σ confidence level), respectively, for projected physical separations larger than ∼60-160 au assuming the range of distances of planet-host stars (24-75 pc). These values are comparable to the frequencies of non planet-host stars. We find that the period-eccentricity trend holds with a lack of multiple systems with planets at large eccentricities (e > 0.2) for periods less than 40 days. However, the lack of planets more massive than 2.5 Jupiter masses and short periods (<40 days) orbiting single stars is not so obvious due to recent discoveries by ground-based transit surveys and space missions.

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“…Several surveys were also carried out with published detection limits for hundreds of objects (e.g., Masciadri et al 2005;Lafrenière et al 2007;Chauvin et al 2010). These observations allowed a first estimate of the frequency of giant planets in wide orbits (Nielsen & Close 2010).…”

Section: Introductionmentioning

confidence: 99%

The VLT/NaCo large program to probe the occurrence of exoplanets and brown dwarfs in wide orbits

Desidera

Covino

Messina

et al. 2015

A&A

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Context. Young, close stars are ideal targets for searching planets using the direct imaging technique. The determination of stellar parameters is crucial for the interpretation of imaging survey results, particularly since the luminosity of substellar objects has a strong dependence on system age. Aims. We have conducted a large program with NaCo at the VLT to search for planets and brown dwarfs in wide orbits around 86 stars. A large fraction of the targets observed with NaCo were poorly investigated in the literature. We performed a study to characterize the fundamental properties (age, distance, and mass) of the stars in our sample. To improve target age determinations, we compiled and analyzed a complete set of age diagnostics. Methods. We measured spectroscopic parameters and age diagnostics using dedicated observations acquired with FEROS and CORALIE spectrographs at La Silla Observatory. We also made extensive use of archival spectroscopic data and the results that are available in the literature. Additionally, we exploited photometric time-series, which are available in ASAS and Super-WASP archives, to derive a rotational period for a large fraction of our program stars. Results. We provided updated characterization of all the targets observed in the VLT NaCo Large program, a survey designed to probe the occurrence of exoplanets and brown dwarfs in wide orbits. The median distance and age of our program stars are 64 pc and 100 Myr, respectively. Nearly all the stars have masses between 0.70 and 1.50 M , with a median value of 1.01 M . The typical metallicity is close to solar with a dispersion that is smaller than that of samples usually observed in radial velocity surveys. Several stars are confirmed or proposed here to be members of close young moving groups. Eight spectroscopic binaries are identified.

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A Search for Hot Massive Extrasolar Planets around Nearby Young Stars with the Adaptive Optics System NACO

Cited by 167 publications

References 51 publications

Performance of the VLT Planet Finder SPHERE

Performance of the VLT Planet Finder SPHERE

Binary frequency of planet-host stars at wide separations

The VLT/NaCo large program to probe the occurrence of exoplanets and brown dwarfs in wide orbits

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