Differential Simultaneous Imaging and Faint Companions: TRIDENT First Results from CFHT

We present the first results obtained at CFHT with the TRIDENT infrared camera, dedicated to the detection of faint companions close to bright nearby stars. Its main feature is the acquisition of three simultaneous images in three wavelengths (simultaneous differential imaging) across the methane absorption bandhead at 1.6μm, that enables a precise subtraction of the primary star PSF while keeping the companion signal. Thirty-five stars have been observed in two observing missions, with no detection so far. It is shown that a faint companion with a ΔH of 10 magnitudes would be detected at 0.5″ from the primary.

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LIStEN: L′ band Imaging Survey for Exoplanets in the North

Astronomy and Astrophysics ◽

10.1051/0004-6361/202039541 ◽

2021 ◽

Vol 645 ◽

pp. A88

Author(s):

Arianna Musso Barcucci ◽

Ralf Launhardt ◽

André Müller ◽

Grant M. Kennedy ◽

Roy van Boekel ◽

...

Keyword(s):

Proper Motion ◽

Major Axis ◽

Mass Detection ◽

Semi Major Axis ◽

Simultaneous Imaging ◽

The North ◽

Nearby Stars ◽

Low Mass ◽

Differential Imaging ◽

By Products

Context. Planetary systems and debris discs are natural by-products of the star formation process, and they affect each other. The direct imaging technique allows simultaneous imaging of both a companion and the circumstellar disc it resides in, and is thus a valuable tool to study companion-disc interactions. However, the number of systems in which a companion and a disc have been detected at the same time remains low. Aims. Our aim is to increase this sample, and to continue detecting and studying the population of giant planets in wide orbits. Methods. We carry out the L′ band Imaging Survey for Exoplanets in the North (LIStEN), which targeted 28 nearby stars: 24 are known to harbour a debris disc (DD) and the remaining 4 are protoplanetary disc-hosting stars. We aim to detect possible new companions, and study the interactions between the companion and their discs. Angular differential imaging observations were carried out in the L′ band at 3.8 μm using the LMIRCam instrument at the LBT, between October 2017 and April 2019. Results. No new companions were detected. We combined the derived mass detection limits with information on the disc, and on the proper motion of the host star, to constrain the presence of unseen planetary and low-mass stellar companion around the 24 disc-hosting stars in our survey. We find that 2 have an uncertain DD status and the remaining 22 have disc sizes compatible with self-stirring. Three targets show a proper motion anomaly (PMa) compatible with the presence of an unseen companion. Conclusions. Our achieved mass limits combined with the PMa analysis for HD 113337 support the presence of a second companion around the star, as suggested in previous RV studies. Our mass limits also help to tighten the constraints on the mass and semi-major axis of the unseen companions around HD 161868 and HD 8907.

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Detectability of Planets in Wide Binaries by Ground-Based Relative Astrometry with AO

Proceedings of the International Astronomical Union ◽

10.1017/s1743921307004139 ◽

2006 ◽

Vol 2 (S240) ◽

pp. 261-263 ◽

Cited By ~ 2

Author(s):

R. Neuhäuser ◽

A. Seifahrt ◽

T. Röll ◽

A. Bedalov ◽

M. Mugrauer

Keyword(s):

Standard Deviation ◽

Radial Velocity ◽

Adaptive Optics ◽

Periodic Variation ◽

Square Root ◽

Primary Star ◽

First Results ◽

Orbit Inclination ◽

Pixel Scale ◽

True Mass

AbstractMany planet candidates have been detected by radial-velocity variations of the primary star; they are planet candidates, because of the unknown orbit inclination. Detection of the wobble in the two other dimensions, to be measured by astrometry, would yield the inclination and, hence, true mass of the companions. We aim to show that planets can be confirmed or discovered in a close visual stellar binary system by measuring the astrometric wobble of the exoplanet host star as a periodic variation of the separation, even from the ground. We test the feasibility with HD 19994, a visual binary with one radial velocity planet candidate. We use the adaptive optics camera NACO at the VLT with its smallest pixel scale (∼ 13 mas) for high-precision astrometric measurements. The separations measured in 120 single images taken within one night are shown to follow white noise, so that the standard deviation can be divided by the square root of the number of images to obtain the precision. In this paper we present the first results and investigate the achievable precision in relative astrometry with adaptive optics. With careful data reduction it is possible to achieve a relative astrometric precision as low as 50 μ as for a 0″.6 binary with VLT/NACO observations in one hour, the best relative astrometric precision ever achieved with a single telescope from the ground. The relative astrometric precision demonstrated here with AO at an 8-m mirror is sufficient to detect the astrometric signal of the planet HD 19994 Ab as periodic variation of the separation between HD 19994 A and B.

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TRIDENT: an infrared camera optimized for the detection of methanated substellar companions of nearby stars

10.1117/12.457844 ◽

2003 ◽

Cited By ~ 3

Author(s):

Christian Marois ◽

Rene Doyon ◽

Daniel Nadeau ◽

Rene Racine ◽

Martin Riopel ◽

...

Keyword(s):

Infrared Camera ◽

Nearby Stars ◽

Substellar Companions

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Status and first results of the Canarias infrared camera experiment (CIRCE) for the Gran Telescopio Canarias

10.1117/12.2057019 ◽

2014 ◽

Author(s):

Alan Garner ◽

Richard D. Stelter ◽

Stephen S. Eikenberry ◽

Nestor Lasso-Cabrera ◽

Steven N. Raines ◽

...

Keyword(s):

Infrared Camera ◽

First Results

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The Spitzer search for the transits of HARPS low-mass planets

Proceedings of the International Astronomical Union ◽

10.1017/s1743921311020138 ◽

2010 ◽

Vol 6 (S276) ◽

pp. 167-170

Author(s):

Michaël Gillon ◽

Brice-Olivier Demory ◽

Drake Deming ◽

Sara Seager ◽

Christophe Lovis ◽

...

Keyword(s):

Large Population ◽

High Signal ◽

Signal To Noise ◽

Close Orbit ◽

Short Period ◽

First Results ◽

Nearby Stars ◽

Low Mass ◽

Set Up

AbstractRadial velocity, microlensing and transit surveys have revealed the existence of a large population of low-mass planets in our Galaxy, the so-called ‘Super-Earths’ and ‘Neptunes’. The understanding of these objects would greatly benefit from the detection of a few of them transiting bright nearby stars, making possible their thorough characterization with high signal-to-noise follow-up measurements. Our HARPS Doppler survey has now detected dozens of low-mass planets in close orbit around bright nearby stars, and it is highly probable that a few of them do transit their host star. In this context, we have set up an ambitious Spitzer program devoted to the search for the transits of the short period low-mass planets detected by HARPS. We present here this program and some of its first results.

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Convective Boiling Between 2D Plates: Shear Flow Influence on Bubble Growth, Detachment and Evolution

Heat Transfer: Volume 2 ◽

10.1115/ht2008-56176 ◽

2008 ◽

Author(s):

D. Serret ◽

D. Brutin ◽

O. Rahli ◽

C. Le Niliot ◽

L. Tadrist

Keyword(s):

Shear Flow ◽

Normal Gravity ◽

Infrared Camera ◽

Video Camera ◽

Nucleation Site ◽

Bubble Nucleation ◽

Vapor Bubbles ◽

Convective Boiling ◽

Infrared Video ◽

First Results

The experiment detailed in this paper presents results obtained on the nucleation, growth and detachment of HFE-7100 vapor bubbles confined in a two-dimensional plane created on an artificial nucleation site. The experiments were performed by varying the shear flow and the bubble nucleation rate through the heat flux supplied under normal gravity and microgravity. The distance between the plates was kept constant at 1 mm. The first results of these experiments are mainly related to the formation of a bubble on an isolated site with or without convection and to the associated heat transfer when confinement is imposed on a bubble. To this effect, we implemented an experimental device allowing the observation of the flow by means of both a visible video camera and an infrared video camera. Here, we present the first results obtained from the campaign performed in December 2007 concerning the influence of gravity on the bubble detachment diameter and the first images of 2D bubbles obtained in microgravity by means of an infrared camera.

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High-resolution survey for planetary companions to young stars in the Taurus molecular cloud

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa2434 ◽

2020 ◽

Vol 498 (1) ◽

pp. 1382-1396

Author(s):

A L Wallace ◽

J Kammerer ◽

M J Ireland ◽

C Federrath ◽

A L Kraus ◽

...

Keyword(s):

Adaptive Optics ◽

Near Infrared ◽

Semimajor Axis ◽

Infrared Camera ◽

Single Class ◽

Hot Start ◽

Guide Star ◽

Laser Guide ◽

Large Telescopes ◽

Differential Imaging

ABSTRACT Direct imaging in the infrared at the diffraction limit of large telescopes is a unique probe of the properties of young planetary systems. We survey 55 single class I and class II stars in Taurus in the L’ filter using natural and laser guide star adaptive optics and the near-infrared camera (NIRC2) of the Keck II telescope, in order to search for planetary-mass companions. We use both reference star differential imaging and kernel phase techniques, achieving typical 5σ contrasts of ∼6 mag at separations of 0.2 arcsec and ∼8 mag beyond 0.5 arcsec. Although, we do not detect any new faint companions, we constrain the frequency of wide separation massive planets, such as HR 8799 analogues. We find that, assuming hot-start models and a planet distribution with power-law mass and semimajor axis indices of −0.5 and −1, respectively, less than 20 per cent of our target stars host planets with masses >2 MJ at separations >10 au.

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Search for cool extrasolar giant planets combining coronagraphy, spectral and angular differential imaging

Proceedings of the International Astronomical Union ◽

10.1017/s1743921313007692 ◽

2013 ◽

Vol 8 (S299) ◽

pp. 21-25

Author(s):

Anne-Lise Maire ◽

Anthony Boccaletti ◽

Julien Rameau ◽

Gaël Chauvin ◽

Anne-Marie Lagrange ◽

...

Keyword(s):

Spectral Properties ◽

Point Sources ◽

Giant Planets ◽

Phase Mask ◽

Evolutionary Models ◽

High Contrast ◽

Contrast Imaging ◽

High Contrast Imaging ◽

Nearby Stars ◽

Differential Imaging

AbstractSpectral differential imaging (SDI) is part of the observing strategy of current and on-going high-contrast imaging instruments on ground-based telescopes. Although it improves the star light rejection, SDI attenuates the signature of off-axis companions to the star, just like angular differential imaging (ADI). However, the attenuation due to SDI has the peculiarity of being dependent on the spectral properties of the companions. To date, no study has investigated these effects. Our team is addressing this problem based on data from a direct imaging survey of 16 stars combining the phase-mask coronagraph, the SDI and the ADI modes of VLT/NaCo. The objective of the survey is to search for cool (Teff<1000-1300 K) giant planets at separations of 5-10 AU orbiting young, nearby stars (<200 Myr, <25 pc). The data analysis did not yield any detections. As for the estimation of the sensivity limits of SDI-processed images, we show that it requires a different analysis than that used in ADI-based surveys. Based on a method using the flux predictions of evolutionary models and avoiding the estimation of contrast, we determine directly the mass sensivity limits of the survey for the ADI processing alone and with the combination of SDI and ADI. We show that SDI does not systematically improve the sensitivity due to the spectral properties and self-subtraction of point sources.

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