A spectroscopy study of nearby late-type stars, possible members of stellar kinematic groups

Maldonado, J.; Martínez-Arnáiz, R.; Eiroa, C.; Montes, D.; Montesinos, B.

doi:10.1051/0004-6361/201014948

Cited by 109 publications

(100 citation statements)

References 115 publications

(192 reference statements)

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“…In addition to this, we have one value of −13.3 ± 0.89 km s −1 , and there are ten values from the VizieR, of which six have associated uncertainties. There are two values from Maldonado et al (2010) that have a huge variation, which are much higher than the level of uncertainty at −13.1 ± 0.1 and −2.6 ± 0.1 km s −1 , and agrees with the work of Griffin (2010). Therefore, this target is classified as a multiple system in this work.…”

Section: B1 Archival Rv Valuessupporting

confidence: 81%

Search for associations containing young stars (SACY)

Elliott

Bayo

Melo

et al. 2014

A&A

129

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Context. Dynamically undisrupted, young populations of stars are crucial in studying the role of multiplicity in relation to star formation. Loose nearby associations provide us with a great sample of close (<150 pc) pre-main sequence (PMS) stars across the very important age range (≈5−70 Myr) to conduct such research. Aims. We characterize the short period multiplicity fraction of the search for associations containing young stars (SACY) sample, accounting for any identifiable bias in our techniques and present the role of multiplicity fractions of the SACY sample in the context of star formation. Methods. Using the cross-correlation technique we identified double-lined and triple-lined spectroscopic systems (SB2/SB3s), in addition to this we computed radial velocity (RV) values for our subsample of SACY targets using several epochs of Fiber-fed Extended Range Optical Spectrograph (FEROS) and Ultraviolet and Visual Echelle Spectrograph (UVES) data. These values were used to revise the membership of each association that was then combined with archival data to determine significant RV variations across different data epochs characteristic of multiplicity; single-lined multiple systems (SB1). Results. We identified seven new multiple systems (SB1s: 5, SB2s: 2). We find no significant difference between the short period multiplicity fraction (F m ) of the SACY sample and that of close star-forming regions (≈1−2 Myr) and the field (F m ≤ 10%). These are seen both as a function of age and as a function of primary mass, M 1 , in the ranges P [1:200 day] and M 2 [0.08 M -M 1 ], respectively. Conclusions. Our results are consistent with the picture of universal star formation, when compared to the field and close star-forming regions (SFRs). We comment on the implications of the relationship between increasing multiplicity fraction with the primary mass within the close companion range in relation to star formation.

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Section: B1 Archival Rv Valuessupporting

confidence: 81%

Search for associations containing young stars (SACY)

Elliott

Bayo

Melo

et al. 2014

A&A

129

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“…Despite the fact that kinematics provide only lower limits to stellar ages (Maldonado et al 2010, and references therein), with this classification we find evidence that the two populations of stars show significantly different distributions in terms of Ca ii H&K emission flux. The Kolmogorov-Smirnov test on the < F HK > we measure confirms this result (top panel in Fig.…”

Section: Variability Vs Activity Vs Agementioning

confidence: 56%

HADES RV Programme with HARPS-N at TNG

Scandariato

Maldonado

Affer

et al. 2017

A&A

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Context. M dwarfs are prime targets for current and future planet search programs, particularly of those focused on the detection and characterization of rocky planets in the habitable zone. In this context, understanding their magnetic activity is important for two main reasons: it affects our ability to detect small planets, and it plays a key role in the characterization of the stellar environment.Aims. We aim to analyze observations of the Ca ii H&K and Hα lines as diagnostics of chromospheric activity for low-activity early-type M dwarfs. Methods. We analyze the time series of spectra of 71 early-type M dwarfs collected in the framework of the HADES project for planet search purposes. The HARPS-N spectra provide simultaneously the Ca ii H&K doublet and the Hα line. We develop a reduction scheme able to correct the HARPS-N spectra for instrumental and atmospheric effects, and to provide also flux-calibrated spectra in units of flux at the stellar surface. The Ca ii H&K and Hα fluxes are then compared with each other, and their time variability is analyzed. Results. We find that the Ca ii H and K flux excesses are strongly correlated with each other, while the Hα flux excess is generally less correlated with the Ca ii H&K doublet. We also find that Hα emission does not increase monotonically with the Ca ii H&K line flux, showing some absorption before being filled in by chromospheric emission when Ca ii H&K activity increases. Analyzing the time variability of the emission fluxes, we derive a tentative estimate of the rotation period (of the order of a few tens of days) for some of the program stars, and the typical lifetime of chromospheric active regions (of the order of a few stellar rotations). Conclusions. Our results are in good agreement with similar previous studies. In particular, we find evidence that the chromospheres of early-type M dwarfs could be characterized by different filaments coverage, affecting the formation mechanism of the Hα line. We also show that chromospheric structure is likely related to spectral type.

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“…Some authors have reported features of low metallicity (e.g., Maldonado et al 2010), but none had classified it as a subdwarf (but see Sandage & Kowal 1986). Its low effective temperature has prevented spectral synthesis analyses on high-resolution spectra.…”

Section: Metallicitymentioning

confidence: 99%

CARMENES input catalogue of M dwarfs

Alonso-Floriano¹,

Morales²,

Caballero³

et al. 2015

A&A

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185

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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A spectroscopy study of nearby late-type stars, possible members of stellar kinematic groups

Cited by 109 publications

References 115 publications

Search for associations containing young stars (SACY)

Search for associations containing young stars (SACY)

HADES RV Programme with HARPS-N at TNG

CARMENES input catalogue of M dwarfs

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