The PRIMA facility phase-referenced imaging and micro-arcsecond astrometry

Delplancke, F.

doi:10.1016/j.newar.2008.04.016

Cited by 72 publications

(42 citation statements)

References 11 publications

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“…The astrometric signature α then directly corresponds to the semi-major axis of the apparent orbit, a app , converted to angular units with the help of the parallax : Astrometric measurements are sometimes only performed in one dimension at a time; examples are Hipparcos or PRIMA (Delplancke 2008). In the case of PRIMA the observing direction is given by the baseline orientation, which is flexible to a certain degree.…”

Section: Summary and Discussionmentioning

confidence: 99%

Mass constraints on substellar companion candidates from the re-reducedHipparcosintermediate astrometric data: nine confirmed planets and two confirmed brown dwarfs

Reffert¹,

Quirrenbach²

2011

A&A

107

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Context. The recently completed re-reduction of the Hipparcos data by van Leeuwen (2007a, Astrophysics and Space Science Library, 350) makes it possible to search for the astrometric signatures of planets and brown dwarfs known from radial velocity surveys in the improved Hipparcos intermediate astrometric data. Aims. Our aim is to put more significant constraints on the orbital parameters which cannot be derived from radial velocities alone, i.e. the inclination and the longitude of the ascending node, than was possible before. The determination of the inclination in particular allows to calculate an unambiguous companion mass, rather than the lower mass limit which can be obtained from radial velocity measurements. Methods. We fitted the astrometric orbits of 310 substellar companions around 258 stars, which were all discovered via the radial velocity method, to the Hipparcos intermediate astrometric data provided by van Leeuwen. Results. Even though the astrometric signatures of the companions cannot be detected in most cases, the Hipparcos data still provide lower limits on the inclination for all but 67 of the investigated companions, which translates into upper limits on the masses of the unseen companions. For nine companions the derived upper mass limit lies in the planetary and for 75 companions in the brown dwarf mass regime, proving the substellar nature of those objects. Two of those objects have minimum masses also in the brown dwarf regime and are thus proven to be brown dwarfs. . Of the others, many are either brown dwarfs or very low mass stars. For Eri, we derive a solution which is very similar to the one obtained using Hubble Space Telescope data.

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Section: Summary and Discussionmentioning

confidence: 99%

Mass constraints on substellar companion candidates from the re-reducedHipparcosintermediate astrometric data: nine confirmed planets and two confirmed brown dwarfs

Reffert¹,

Quirrenbach²

2011

A&A

107

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“…Thanks to their high photometric precision and continuous monitoring of rich stellar fields, the recently launched CoRoT 1 and Kepler 2 missions will initiate large-scale planet searches around eclipsing binaries (Doyle & Deeg 2004;Ofir et al 2009; see also the contribution by Sybilski). Alternatively, new interferometric facilities like PRIMA at the Very Large Telescope Interferometer (Delplancke 2008) or the AS-TRA upgrade of the Keck Interferometer (Pott et al 2008) will allow to extend astrometric planet searches to significantly wider and fainter binaries. The upcoming generation of high-contrast adaptive optics instruments such as HiCIAO at Subaru (Tamura et al 2006), GPI at Gemini South (Macintosh et al 2008), SPHERE at the Very Large Telescope (Beuzit et al 2008) and PALM-3000/Project-1640 at Palomar (Bouchez et al 2008) will also likely be used to carry out systematic searches for giant planets in some types of moderately close binaries.…”

Section: Discussionmentioning

confidence: 99%

Detection and Characterization of Planets in Binary and Multiple Systems

Eggenberger

2010

EAS Publications Series

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Abstract. Moderately close binaries are a special class of targets for planet searches. From a theoretical standpoint, their hospitality to giant planets is uncertain and debated. From an observational standpoint, many of these systems present technical difficulties for precise radial-velocity measurements and classical Doppler surveys avoid them accordingly. In spite of these adverse factors, present data support the idea that giant planets residing in binary and hierarchical systems provide unique observational constraints on the processes of planet formation and evolution. The interest and the importance of including various types of binary stars in extrasolar planet studies have thus grown over time and significant efforts have recently been put into: (i) searching for stellar companions to the known planet-host stars using direct imaging, and (ii) extending Doppler planet searches to spectroscopic and moderately close visual binaries. In this contribution we review the observational progresses made over the past years to detect and study extrasolar planets in binary systems, putting special emphasis on the two developments mentioned above.

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“…In the case of the VLT Interferometer (VLTI), longitudinal vibrations on the level of the baselines cause fringes to move onto the detector. Power spectra of sequences of OPD values estimated during a run on the VLTI/PRIMA instrument (Delplancke 2008) indicate the presence of a discrete number of vibration components during fringe observations (Sahlmann et al 2009). In an effort to reduce the vibration level of the VLTI A&A 541, A81 (2012) system, a campaign to identify the contribution of different VLT subsystems has been initiated Poupar et al 2010).…”

Section: Introductionmentioning

confidence: 99%

Kalman-filter control schemes for fringe tracking

Perrin

Choquet

et al. 2012

A&A

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Context. The implementation of fringe tracking for optical interferometers is inevitable when optimal exploitation of the instrumental capacities is desired. Fringe tracking allows continuous fringe observation, considerably increasing the sensitivity of the interferometric system. In addition to the correction of atmospheric path-length differences, a decent control algorithm should correct for disturbances introduced by instrumental vibrations, and deal with other errors propagating in the optical trains. Aims. In an effort to improve upon existing fringe-tracking control, especially with respect to vibrations, we attempt to construct control schemes based on Kalman filters. Kalman filtering is an optimal data processing algorithm for tracking and correcting a system on which observations are performed. As a direct application, control schemes are designed for GRAVITY, a future four-telescope near-infrared beam combiner for the Very Large Telescope Interferometer (VLTI). Methods. We base our study on recent work in adaptive-optics control. The technique is to describe perturbations of fringe phases in terms of an a priori model. The model allows us to optimize the tracking of fringes, in that it is adapted to the prevailing perturbations. Since the model is of a parametric nature, a parameter identification needs to be included. Different possibilities exist to generalize to the four-telescope fringe tracking that is useful for GRAVITY. Results. On the basis of a two-telescope Kalman-filtering control algorithm, a set of two properly working control algorithms for four-telescope fringe tracking is constructed. The control schemes are designed to take into account flux problems and low-signal baselines. First simulations of the fringe-tracking process indicate that the defined schemes meet the requirements for GRAVITY and allow us to distinguish in performance. In a future paper, we will compare the performances of classical fringe tracking to our Kalman-filter control. Conclusions. Kalman-filter based control schemes will likely become the next standard for fringe tracking, providing the possibility to maximize the tracking performance. The results of the present study are currently being incorporated into the final design of GRAVITY.

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The PRIMA facility phase-referenced imaging and micro-arcsecond astrometry

Cited by 72 publications

References 11 publications

Mass constraints on substellar companion candidates from the re-reducedHipparcosintermediate astrometric data: nine confirmed planets and two confirmed brown dwarfs

Mass constraints on substellar companion candidates from the re-reducedHipparcosintermediate astrometric data: nine confirmed planets and two confirmed brown dwarfs

Detection and Characterization of Planets in Binary and Multiple Systems

Kalman-filter control schemes for fringe tracking

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