Reaching the boundary between stellar kinematic groups and very wide binaries

Alonso-Floriano, F. J.; Caballero, J. A.; Cortés-Contreras, M.; Solano, E.; Montes, D.

doi:10.1051/0004-6361/201526795

Cited by 45 publications

(43 citation statements)

References 144 publications

(150 reference statements)

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“…Our DuPont/BC832 spectroscopy supports the classification of TYC 9114-1267-1 as K7 (Torres et al 2006). The (∼40 Myr) age we estimate for TYC 9114-1267-1 and our Li absorption line upper limit (<60 mÅ) are consistent with Tuc-Hor membership for the V390 Pav plus TYC 9114-1267-1 system (WDS 21214-6655) and appears to rule out βPMG membership for this system (see also Schlieder et al 2010;Alonso-Floriano et al 2015). On the other hand, while the TGAS parallaxes of V390 Pav (π =31.24±0.26 mas) and TYC 9114-1267-1 (π =31.1±0.…”

Section: Components (And Potential Components) Of Wide Binariessupporting

confidence: 81%

Nearby Young, Active, Late-type Dwarfs in Gaia's First Data Release

Kastner

Sacco

Rodríguez

et al. 2017

ApJ

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The Galex Nearby Young Star Survey (GALNYSS) has yielded a sample of ∼2000 UV-selected objects that are candidate nearby (D < ∼150 pc), young (age ∼10-100 Myr), late-type stars. Here, we evaluate the distances and ages of the subsample of (19) GALNYSS stars with Gaia Data Release 1 (DR1) parallax distances D ≤ 120 pc. The overall youth of these 19 mid-K to early-M stars is readily apparent from their positions relative to the loci of main sequence stars and giants in Gaia-based color-magnitude and color-color diagrams constructed for all stars detected by Galex and the Wide-field Infrared Space Explorer for which parallax measurements are included in DR1. The isochronal ages of all 19 stars lie in the range ∼10-100 Myr. Comparison with Li-based age estimates indicates a handful of these stars may be young main-sequence binaries rather than pre-main sequence stars. Nine of the 19 objects have not previously been considered as nearby, young stars, and all but one of these are found at declinations north of +30• . The Gaia DR1 results presented here indicate that the GALNYSS sample includes several hundred nearby, young stars, a substantial fraction of which have not been previously recognized as having ages < ∼100 Myr.

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Section: Components (And Potential Components) Of Wide Binariessupporting

confidence: 81%

Nearby Young, Active, Late-type Dwarfs in Gaia's First Data Release

Kastner

Sacco

Rodríguez

et al. 2017

ApJ

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“…The targets identified in this work are candidate wide companions to these previously identified highprobability members. In that respect this work differs from the majority of previous works aimed at identifying new members and is more similar to works related to wide binaries (Caballero 2009(Caballero , 2010Alonso-Floriano et al 2015). The formation mechanism and implications of such wide (1000−100 000 au) companions will be discussed in further work.…”

Section: Introductionmentioning

confidence: 73%

“…We also compared our results to other works that have focussed on very wide companions to stars in the moving groups ( Kastner et al 2011Kastner et al , 2012Scholz et al 2005;Looper et al 2010;Feigelson et al 2006;Alonso-Floriano et al 2015). A detailed comparison of these targets can be found in Appendix B. Additionally we queried Simbad (Wenger et al 2000) for each object to collate any noteworthy features, analysis, and further parameters available.…”

Section: Further Information From Catalogues and Literaturementioning

confidence: 99%

Search for associations containing young stars (SACY)

Elliott

Bayo

Melo

et al. 2016

A&A

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Context. The young associations offer us one of the best opportunities to study the properties of young stellar and substellar objects and to directly image planets thanks to their proximity (<200 pc) and age (≈5−150 Myr). However, many previous works have been limited to identifying the brighter, more active members (≈1 M ) owing to photometric survey sensitivities limiting the detections of lower mass objects. Aims. We search the field of view of 542 previously identified members of the young associations to identify wide or extremely wide (1000−100 000 au in physical separation) companions. Methods. We combined 2MASS near-infrared photometry (J, H, K) with proper motion values (from UCAC4, PPMXL, NOMAD) to identify companions in the field of view of known members. We collated further photometry and spectroscopy from the literature and conducted our own high-resolution spectroscopic observations for a subsample of candidate members. This complementary information allowed us to assess the efficiency of our method. Results. We identified 84 targets (45: 0.2−1.3 M , 17: 0.08−0.2 M , 22: <0.08 M ) in our analysis, ten of which have been identified from spectroscopic analysis in previous young association works. For 33 of these 84, we were able to further assess their membership using a variety of properties (X-ray emission, UV excess, H α , lithium and K I equivalent widths, radial velocities, and CaH indices). We derive a success rate of 76-88% for this technique based on the consistency of these properties. Conclusions. Once confirmed, the targets identified in this work would significantly improve our knowledge of the lower mass end of the young associations. Additionally, these targets would make an ideal new sample for the identification and study of planets around nearby young stars. Given the predicted substellar mass of the majority of these new candidate members and their proximity, high-contrast imaging techniques would facilitate the search for new low-mass planets.

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“…Spectral types from V * − J colours are not suitable for our purposes (Alonso-Floriano et al 2013a;Mundt et al 2013;Lépine et al 2013 -V * is an average of photographic magnitudes B J and R F from the Digital Sky Survey; cf. Lépine & Gaidos 2011).…”

Section: Cafos Samplementioning

confidence: 99%

“…The present publication on low-resolution spectroscopy is the first paper of a series aimed at describing the selection and characterisation of the CARMENES sample. We have shown some preliminary results at conferences before that described the input catalogue description and selection Morales et al 2013), low-resolution spectroscopy (Klutsch et al 2012;Alonso-Floriano et al 2013a), high-resolution spectroscopy (Alonso-Floriano et al 2013b;Passegger et al 2014), resolved multiplicity (Béjar et al 2012;Cortés-Contreras et al 2013), X-rays (Lalitha et al 2012), exploitation of public databases , or synergies with Kepler K2 (Rodríguez-López et al 2014). This first item of the CARMENES science-preparation series details the low-resolution optical spectroscopy of M dwarfs with the CAFOS spectrograph at the Zeiss 2.2 m Calar Alto telescope.…”

Section: Introductionmentioning

confidence: 96%

CARMENES input catalogue of M dwarfs

Alonso-Floriano¹,

Morales²,

Caballero³

et al. 2015

A&A

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195

178

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Context. CARMENES is a stabilised, high-resolution, double-channel spectrograph at the 3.5 m Calar Alto telescope. It is optimally designed for radial-velocity surveys of M dwarfs with potentially habitable Earth-mass planets. Aims. We prepare a list of the brightest, single M dwarfs in each spectral subtype observable from the northern hemisphere, from which we will select the best planet-hunting targets for CARMENES. Methods. In this first paper on the preparation of our input catalogue, we compiled a large amount of public data and collected lowresolution optical spectroscopy with CAFOS at the 2.2 m Calar Alto telescope for 753 stars. We derived accurate spectral types using a dense grid of standard stars, a double least-squares minimisation technique, and 31 spectral indices previously defined by other authors. Additionally, we quantified surface gravity, metallicity, and chromospheric activity for all the stars in our sample. Results. We calculated spectral types for all 753 stars, of which 305 are new and 448 are revised. We measured pseudo-equivalent widths of Hα for all the stars in our sample, concluded that chromospheric activity does not affect spectral typing from our indices, and tabulated 49 stars that had been reported to be young stars in open clusters, moving groups, and stellar associations. Of the 753 stars, two are new subdwarf candidates, three are T Tauri stars, 25 are giants, 44 are K dwarfs, and 679 are M dwarfs. Many of the 261 investigated dwarfs in the range M4.0-8.0 V are among the brightest stars known in their spectral subtype. Conclusions. This collection of low-resolution spectroscopic data serves as a candidate target list for the CARMENES survey and can be highly valuable for other radial-velocity surveys of M dwarfs and for studies of cool dwarfs in the solar neighbourhood.

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Reaching the boundary between stellar kinematic groups and very wide binaries

Cited by 45 publications

References 144 publications

Nearby Young, Active, Late-type Dwarfs in Gaia's First Data Release

Nearby Young, Active, Late-type Dwarfs in Gaia's First Data Release

Search for associations containing young stars (SACY)

CARMENES input catalogue of M dwarfs

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