Astrometric and spectroscopic confirmation  of a brown dwarf companion to GSC 08047-00232

Chauvin, G.; Lagrange, A.-M.; Lacombe, F.; Dumas, Christophe; Mouillet, D.; Zuckerman, B.; Gendron, É.; Song, Inseok; Beuzit, J. L.; Lowrance, P.; Fusco, Thierry

doi:10.1051/0004-6361:20041353

Cited by 38 publications

(31 citation statements)

References 33 publications

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“…Our strategy has been sucessful with the confirmation of a brown dwarf companion to GSC 08047-00232 (Chauvin et al 2003(Chauvin et al , 2005a and discoveries of a planetary mass companion to the young brown dwarf 2MASSW J1207334-393254 (hereafter 2M1207; Chauvin et al 2004;2005c) and a companion at the planet/brown dwarf boundary to the young star AB Pic (Chauvin et al 2005b).…”

Section: Resultsmentioning

confidence: 99%

“…Many such stars reside in several coeval moving groups (e.g., TWA, β Pictoris, Tucana-Horologium, η Cha, AB Dor, Columba and Carinae), sharing common kinematics, photometric and spectroscopic properties (see Zuckerman & Song 2004, hereafter ZS04;Torres et al 2008, T08). A few young brown dwarf companions have been detected from space, HR 7329 B and TWA5 B (Lowrance et al 2000(Lowrance et al , 1999, and from the ground, GSC 08047-00232 B (Chauvin et al 2005a). Companions down to the planetary mass regime were discovered around the star AB Pic (Chauvin et al 2005c) and the young brown dwarf 2M1207 (Chauvin et al 2004(Chauvin et al , 2005b.…”

Section: Introductionmentioning

confidence: 99%

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Deep imaging survey of young, nearby austral stars

Chauvin¹,

Lagrange²,

Bonavita

et al. 2010

A&A

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Context. High contrast and high angular resolution imaging is the optimal search technique for substellar companions to nearby stars at physical separations larger than typically 10 AU. Two distinct populations of substellar companions, brown dwarfs and planets, can be probed and characterized. As a result, fossile traces of processes of formation and evolution can be revealed by physical and orbital properties, both for individual systems and as an ensemble. Aims. Since November 2002, we have conducted a large, deep imaging, survey of young, nearby associations of the southern hemisphere. Our goal is detection and characterization of substellar companions with projected separations in the range 10-500 AU. We have observed a sample of 88 stars, primarily G to M dwarfs, younger than 100 Myr, and within 100 pc of Earth. Methods. The VLT/NACO adaptive optics instrument of the ESO Paranal Observatory was used to explore the faint circumstellar environment between typically 0.1 and 10 . Diffraction-limited observations in H and K s -band combined with Lyot-coronagraphy enabled us to reach primary star-companion brightness ratios as small as 10 −6 . The existence of planetary mass companions could therefore be probed. We used a standardized observing sequence to precisely measure the position and flux of all detected sources relative to their visual primary star. Repeated observations at several epochs enabled us to discriminate comoving companions from background objects. Results. We report the discovery of 17 new close (0.1-5.0 ) multiple systems. HIP 108195 AB and C (F1 III-M6), HIP 84642 AB (a ∼ 14 AU, K0-M5) and TWA22 AB (a ∼ 1.8 AU; M6-M6) are confirmed comoving systems. TWA22 AB is likely to be a rare astrometric calibrator that can be used to test evolutionary model predictions. Among our complete sample, a total of 65 targets were observed with deep coronagraphic imaging. About 240 faint companion candidates were detected around 36 stars. Follow-up observations with VLT or HST for 83% of these stars enabled us to identify a large fraction of background contaminants. Our latest results that pertain to the substellar companions to GSC 08047-00232, AB Pic and 2M1207 (confirmed during this survey and published earlier), are reviewed. Finally, a statistical analysis of our complete set of coronagraphic detection limits enables us to place constraints on the physical and orbital properties of giant planets between typically 20 and 150 AU.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Deep imaging survey of young, nearby austral stars

Chauvin¹,

Lagrange²,

Bonavita

et al. 2010

A&A

Self Cite

180

225

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“…However, its near-IR gravity status is uncertain, as Allers & Liu (2013a) type this object as L6 int-g but Gagné et al (2015a) typed it as L6p with no clear sign of low gravity. TVLM831-154910 has a parallax from Tinney et al (1995) and has recently been typed as M7:β vl-g and identified 5 Four well-known young ultracool companions are not included in our compilation as their primary stars lack parallaxes: GSC 08047−00232 B (M9.5±1, Tuc-Hor member; Chauvin et al 2003;Neuhäuser & Guenther 2004;Chauvin et al 2005a), 1RXS J235133.3+312720 (L0 +2 −1 , probable AB Dor member; Bowler et al 2012), 2MASS J01225093−2439505 B (L3.7±1.0, probable AB Dor member; Bowler et al 2013;Hinkley et al 2015), and GU Psc b (T3.5±1, probable AB Dor member; Naud et al 2014).…”

Section: Objects Not Included In Our Analysismentioning

confidence: 99%

The Hawaii Infrared Parallax Program. Ii. Young Ultracool Field Dwarfs* †

Liu

Dupuy

Allers

2016

ApJ

233

320

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We present a large, uniform analysis of young (≈10-150 Myr) ultracool dwarfs, based on new high-precision infrared (IR) parallaxes for 68 objects. We find that low-gravity (vl-g) late-M and L dwarfs form a continuous sequence in IR color-magnitude diagrams, separate from the field population and from current theoretical models. These vl-g objects also appear distinct from young substellar (brown dwarf and exoplanet) companions, suggesting the two populations may have a different range of physical properties. In contrast, at the L/T transition, young, old, and spectrally peculiar objects all span a relatively narrow range in near-IR absolute magnitudes. At a given spectral type, the IR absolute magnitudes of young objects can be offset from ordinary field dwarfs, with the largest offsets occurring in the Y and J bands for late-M dwarfs (brighter than the field) and mid/late-L dwarfs (fainter than the field). Overall, low-gravity (vl-g) objects have the most uniform photometric behavior while intermediate-gravity (int-g) objects are more diverse, suggesting a third governing parameter beyond spectral type 1 This work is largely based on observations obtained with WIRCam, a joint project of CFHT, Taiwan, Korea, Canada, France, and the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique of France, and the University of Hawaii.2 Some of the data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation. -2 -and gravity class. We examine the moving group membership for all young ultracool dwarfs with parallaxes, changing the status of 23 objects (including 8 previously identified planetary-mass candidates) and fortifying the status of another 28 objects. We use our resulting age-calibrated sample to establish empirical young isochrones and show a declining frequency of vl-g objects relative to int-g objects with increasing age. Notable individual objects in our sample include high-velocity ( 100 km s −1 ) int-g objects; very red late-L dwarfs with high surface gravities; candidate disk-bearing members of the MBM20 cloud and β Pic moving group; and very young distant interlopers. Finally, we provide a comprehensive summary of the absolute magnitudes and spectral classifications of young ultracool dwarfs, using a combined sample of 102 objects found in the field and as substellar companions to young stars.Subject headings: brown dwarfs -proper motions -parallaxes -solar neighborhood IntroductionObservational studies of brown dwarfs have been inspired by two complementary perspectives. One has been the desire to expand the parameter space of classical stellar astrophysics. Brown dwarfs are t...

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“…It is sensitive to intrinsically bright objects (low-mass stars, brown dwarfs, and young giant planets), and it brings essential insight to the possible origins of these objects . Direct near-infrared imaging allowed observers to detect several kinds of substellar companions, such as brown dwarfs (e.g., Nakajima et al 1995;Lowrance et al 1999Lowrance et al , 2000Chauvin et al 2005a), objects at the transition between brown dwarfs and planets (e.g., Chauvin et al 2005b), or planetary-mass objects such as 2M1207b in orbit around a brown dwarf (Chauvin et al 2004(Chauvin et al , 2005c, all of which are probably not formed through core-accretion like planets detected by velocimetry, but rather as multiple stars via a cloud fragmentation process or as brown dwarfs through disc fragmentation (see, e.g., Lodato et al 2005). These detections nevertheless show that star-forming mechanisms can be efficient down to planetary masses.…”

Section: Introductionmentioning

confidence: 99%

Deep infrared imaging of close companions to austral A- and F-type stars

Ehrenreich

Lagrange

Montagnier

et al. 2010

A&A

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The search for substellar companions around stars with different masses along the main sequence is critical to understanding the different processes leading to the formation of low-mass stars, brown dwarfs, and planets. In particular, the existence of a large population of low-mass stars and brown dwarfs physically bound to early-type main-sequence stars could imply that the massive planets recently imaged at wide separations (10-100 AU) around A-type stars are disc-born objects in the low-mass tail of the binary distribution and are thus formed via gravitational instability rather than by core accretion. Our aim is to characterize the environment of early-type main-sequence stars by detecting substellar companions between 10 and 500 AU. The sample stars are also surveyed with radial velocimetry, providing a way to determine the impact of the imaged companions on planets at < ∼ 10 AU. High-contrast and high angular resolution near-infrared images of a sample of 38 southern A-and F-type stars were obtained between 2005 and 2009 with the instruments NaCo on the Very Large Telescope and PUEO on the Canada-France-Hawaii Telescope. Direct and saturated imaging were used in the J to K s bands to probe the faint circumstellar environments with contrasts of ∼5 × 10 −2 to 10 −4 at separations of 0. 2 and 1 , respectively. Using coronagraphic imaging, we achieved contrasts between 10 −5 and 10 −6 at separations >5 . Multiepoch observations were performed to distinguish comoving companions from background contaminants. This survey is sensitive to companions of A and F stars in the brown dwarf to low-mass star mass regime. About 41 companion candidates were imaged around 23 stars. Follow-up observations for 83% of these stars allowed us to identify a large number of background contaminants. We report detection of 7 low-mass stars with masses between 0.1 and 0.8 M in 6 multiple systems: the discovery of an M2 companion around the A5V star HD 14943 and detection of HD 41742B around the F4V star HD 41742 in a quadruple system. We resolve the known companion of the F6.5V star HD 49095 as a short-period binary system composed of 2 M/L dwarfs. We also resolve the companions to the astrometric binaries ι Crt (F6.5V) and 26 Oph (F3V), and identify an M3/M4 companion to the F4V star o Gru, associated with an X-ray source. The global multiplicity fraction measured in our sample of A and F stars is ≥16%. This has a probable impact on the radial velocity measurements performed on the sample stars.

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Astrometric and spectroscopic confirmation of a brown dwarf companion to GSC 08047-00232

Cited by 38 publications

References 33 publications

Deep imaging survey of young, nearby austral stars

Deep imaging survey of young, nearby austral stars

The Hawaii Infrared Parallax Program. Ii. Young Ultracool Field Dwarfs* †

Deep infrared imaging of close companions to austral A- and F-type stars

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