New
                    <i>Hipparcos</i>
                    ‐based Parallaxes for 424 Faint Stars

Gould, Andrew; Chanamé, Julio

doi:10.1086/381147

Cited by 91 publications

(70 citation statements)

References 15 publications

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“…The spectra of stars brighter than J = 9.0 mag were published by Lépine et al (2013), while most of the remaining fainter ones are published here. -M dwarf candidates in nearby young moving groups (e.g., Montes et al 2001;Zuckermann & Song 2004;da Silva et al 2009;Shkolnik et al 2012;Gagné et al 2014;Klutsch et al 2014), in multiple systems containing FGK-type primaries that are subjects of metallicity studies (Gliese & Jahreiss 1991;Poveda et al 1994;Gould & Chanamé 2004;Rojas-Ayala et al 2012;Terrien et al 2012;Mann et al 2013;Montes et al 2013), in fragile binary systems at the point of disruption by the Galactic gravitational field (Caballero 2012, and references therein), and resulting from new massive virtual-observatory searches (Jiménez-Esteban et al 2012;Aberasturi et al 2014). Such a broad diversity of sources allowed us to widen the investigated intervals of age, activity, multiplicity, metallicity, and dynamical evolution.…”

Section: Cafos Samplementioning

confidence: 99%

CARMENES input catalogue of M dwarfs

Alonso-Floriano¹,

Morales²,

Caballero³

et al. 2015

A&A

186

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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Section: Cafos Samplementioning

confidence: 99%

CARMENES input catalogue of M dwarfs

Alonso-Floriano¹,

Morales²,

Caballero³

et al. 2015

A&A

186

178

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“…Another small ζ parameter star is LSPM J2319+7900S. This star is a common proper motion companion to HD 220140 (Gould & Chanamé 2004), which is a mildly metal-poor G dwarf ([F e/H] = −0.52, [α/H] = 0.20, Casagrande et al 2011). Overall, 29 of 1399 objects have ζ 0.80, suggesting that only ∼2% of this sample could be high C/O ratio M dwarfs, but many (if not all) are metal-poor.…”

Section: Observational Constraintsmentioning

confidence: 99%

M dwarfs and the fraction of high carbon-to-oxygen stars in the solar neighbourhood

Gizis

Marks

Hauschildt³

2015

Mon. Not. R. Astron. Soc.

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We investigate the frequency of high carbon-to-oxygen (C/O = 0.9) M dwarf stars in the solar neighbourhood. Using synthetic spectra, we find that such M dwarfs would have weaker TiO bands relative to hydride features. Similar weakening has already been detected in M-subdwarf (sdM) stars. By comparing to existing spectroscopic surveys of nearby stars, we show that less than one percent of nearby stars have high carbon-to-oxygen ratios. This limit does not include stars with C/O= 0.9, [m/H]> 0.3, and [C/Fe]> 0.1, which we predict to have low-resolution optical spectra similar to solar metallicity M dwarfs.

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“…Using archived surveys along with state-of-the-art follow-up observations enables the combination of different data sources (Caballero et al 2010;Alonso-Floriano et al 2011), offers a way for accurate indirect determinations of quantities like parallax (Gould & Chanamé 2004) or the evolutionary status (Makarov et al 2008), and provides a starting point for extended surveys (like the Palomar/Keck survey of Metchev & Hillenbrand 2009), as well as extreme findings (like the wide ultra-cool binary by Caballero 2007).…”

Section: Multiplicitymentioning

confidence: 99%

The Hercules-Lyra association revisited

Eisenbeiss

Eiff

Roell

et al. 2013

A&A

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Context. The Hercules-Lyra association, a purported nearby young moving group, contains a few tens of zero age main sequence stars of spectral types F to M. The existence and the properties of the Her-Lyr association are controversial and have been discussed in the literature. Aims. The present work reassesses the properties and the member list of the Her-Lyr association based on kinematics and age indicators. Many objects form multiple systems or have low-mass companions and so we need to properly account for multiplicity. Methods. We use our own new imaging observations and archival data to identify multiple systems. The colors and magnitudes of kinematic candidates are compared to isochrones. We derive further information on the age based on Li depletion, rotation, and coronal and chromospheric activity. A set of canonical members is identified to infer mean properties. Membership criteria are derived from the mean properties and used to discard non-members. Results. The candidates selected from the literature belong to 35 stellar systems, 42.9% of which are multiple. Four multiple systems (V538 Aur, DX Leo, V382 Ser, and HH Leo) are confirmed in this work by common proper motion. An orbital solution is presented for the binary system which forms a hierarchical triple with HH Leo. Indeed, a group of candidates displays signatures of youth. Seven canonical members are identified The distribution of Li equivalent widths of canonical Her-Lyr members is spread widely and is similar to that of the Pleiades and the UMa group. Gyrochronology gives an age of 257 ± 46 Myr which is roughly in between the ages of the Pleiades and the Ursa Major group. The measures of chromospheric and coronal activity support the young age. Four membership criteria are presented based on kinematics, lithium equivalent width, chromospheric activity, and gyrochronological age. In total, eleven stars are identified as certain members including co-moving objects plus additional 23 possible members while 14 candidates are doubtful or can be rejected. A comparison to the mass function, however, indicates the presence of a large number of additional low-mass members, which remain unidentified.

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New Hipparcos ‐based Parallaxes for 424 Faint Stars

Cited by 91 publications

References 15 publications

CARMENES input catalogue of M dwarfs

CARMENES input catalogue of M dwarfs

M dwarfs and the fraction of high carbon-to-oxygen stars in the solar neighbourhood

The Hercules-Lyra association revisited

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