Chromospheric Activity and Orbital Solution of Six New Late-type Spectroscopic Binary Systems

Gálvez, M. C.; Montes, D.; Fernández-Figueroa, M. J.; López‐Santiago, J.

doi:10.1007/s10509-006-9074-3

Cited by 22 publications

(28 citation statements)

References 6 publications

(7 reference statements)

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“…No selection cut was applied on projected rotational velocities; all stars in this sample have measured v i sin values in the literature ranging from 2 to 70 km s −1 . All <2″ binaries were rejected from the sample, except for GJ3305AB (0 093; Kasper et al 2007) and HD160934AB (0 12; Gálvez et al 2006), which were not known to be binary stars at the time when the young sample was assembled. A total of 15 targets were selected and are listed in Table 1, with spectral types ranging from K2 to M4.…”

Section: The Young Samplementioning

confidence: 99%

A High-Precision Near-Infrared Survey for Radial Velocity Variable Low-Mass Stars Using Cshell and a Methane Gas Cell

Gagné

Plavchan

Gao

et al. 2016

ApJ

232

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We present the results of a precise near-infrared (NIR) radial velocity (RV) survey of 32 low-mass stars with spectral types K2-M4 using CSHELL at the NASA InfraRed Telescope Facility in the K band with an isotopologue methane gas cell to achieve wavelength calibration and a novel, iterative RV extraction method. We surveyed 14 members of young (≈25-150 Myr) moving groups, the young field star εEridani, and 18 nearby (<25 pc) low-mass stars and achieved typical single-measurement precisions of 8-15 m s −1 with a long-term stability of 15-50 m s −1 over longer baselines. We obtain the best NIR RV constraints to date on 27 targets in our sample, 19 of which were never followed by high-precision RV surveys. Our results indicate that very active stars can display long-term RV variations as low as ∼25-50 m s −1 at ≈2.3125 μm, thus constraining the effect of jitter at these wavelengths. We provide the first multiwavelength confirmation of GJ876bc and independently retrieve orbital parameters consistent with previous studies. We recovered RV variabilities for HD160934AB and GJ725AB that are consistent with their known binary orbits, and nine other targets are candidate RV variables with a statistical significance of 3σ-5σ. Our method, combined with the new iSHELL spectrograph, will yield long-term RV precisions of 5 m s −1 in the NIR, which will allow the detection of super-Earths near the habitable zone of mid-M dwarfs.

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Section: The Young Samplementioning

confidence: 99%

A High-Precision Near-Infrared Survey for Radial Velocity Variable Low-Mass Stars Using Cshell and a Methane Gas Cell

Gagné

Plavchan

Gao

et al. 2016

ApJ

232

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“…In addition, the different age estimates agree very well and confirm that it is a young star; furthermore, the star is known to have IR-excess at 70 μm, see (Reid et al 1995;). This object is a flare star identified as a spectroscopic binary by Gálvez et al (2006). A close companion was detected using lucky imaging techniques by Hormuth et al (2007).…”

Section: Membership and Properties Of The Local Association Candidatesmentioning

confidence: 99%

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

Maldonado¹,

Martínez-Arnáiz

Eiroa³

et al. 2010

A&A

Self Cite

109

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Context. Nearby late-type stars are excellent targets for seeking young objects in stellar associations and moving groups. The origin of these structures is still misunderstood, and lists of moving group members often change with time and also from author to author. Most members of these groups have been identified by means of kinematic criteria, leading to an important contamination of previous lists by old field stars. Aims. We attempt to identify unambiguous moving group members among a sample of nearby-late type stars by studying their kinematics, lithium abundance, chromospheric activity, and other age-related properties. Methods. High-resolution echelle spectra (R ∼ 57 000) of a sample of nearby late-type stars are used to derive accurate radial velocities that are combined with the precise Hipparcos parallaxes and proper motions to compute galactic-spatial velocity components. Stars are classified as possible members of the classical moving groups according to their kinematics. The spectra are also used to study several age-related properties for young late-type stars, i.e., the equivalent width of the lithium Li i 6707.8 Å line or the R HK index. Additional information like X-ray fluxes from the ROSAT All-Sky Survey or the presence of debris discs is also taken into account. The different age estimators are compared and the moving group membership of the kinematically selected candidates are discussed. Results. From a total list of 405 nearby stars, 102 have been classified as moving group candidates according to their kinematics. i.e., only ∼25.2% of the sample. The number reduces when age estimates are considered, and only 26 moving group candidates (25.5% of the 102 candidates) have ages in agreement with the star having the same age as an MG member.

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“…Despite this intense activity, no radio emission has been reported so far. The existence of a close companion (HD 160934 c) around the main star (HD 160934 A) was first reported by Gálvez et al (2006) from radial velocity measurements; in addition, relative astrometry was provided by Hormuth et al (2007) and Lafrenière et al (2007). A combined analysis of all previous data, including new precise relative astrometry from aperture-masking interferometry, has been undertaken by Evans et al (2012) to derive a period of ∼3764 days, semimajor axis of ∼152.5 mas (5.05 AU), and a total mass for both stars of 1.21±0.27 M ⊙ .…”

Section: Introductionmentioning

confidence: 88%

“…Regarding the effective temperatures, we derived a value for component A from its spectral type (K7−K8, McCarthy & White 2012) using the empirical color-temperature transformation reported by Hartigan et al (1994). For component c, we proceed in a similar way by assuming a M2−3 spectral type (Gálvez et al 2006), estimated from the unresolved H−K color and flux ratios in Table 6.2. Final values for the effective temperature were 3940±60 K and 3425±80 K for component A and c, respectively.…”

Section: Observations and Data Reduction 621 Astralux Observationsmentioning

confidence: 99%

Radio Emission from Binary Stars in the AB Doradus Moving Group

et al. 2015

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Que la presente memoria, titulada Radio emission of binary stars in the AB Doradus moving group, ha sido realizada en el Departamento de Astronomía y Astrofísica de la Universidad de Valencia por Rebecca Azulay Romero bajo su dirección y constituye su Tesis Doctoral para optar al grado de Doctor en Ciencias Físicas. Valencia, 7 de abril de 2016Fdo. José Carlos Guirado Puerta Acknowledgements En enero de 2013 empecé el doctorado pocos días después del peor momento de mi vida: el fallecimiento de mi padre. No ha sido un camino fácil, pero la inestimable ayuda de un montón de grandes personas, tanto dentro del ámbito científico como fuera de él, han hecho que esta experiencia haya valido mucho la pena.En primer lugar, agradecer al grupo de Radioastronomía de la Universidad de Valencia el haberme dado la posibilidad de hacer con ellos esta tesis doctoral. Somos un grupo pequeño, pero muy competente a nivel científico.Mil gracias a mi director de tesis, José Carlos Guirado, por todo lo que ha hecho por mí, profesionalmente y personalmente, ¡que sé que convivir conmigo día a día no es algo sencillo! Gracias por confiar en mí en todo momento, por guiarme y orientarme cada vez que lo he necesitado, por tu experiencia, por tus consejos y por tu paciencia. Nada de esto hubiese sido posible sin todo lo que me has enseñado y apoyado.Gracias también a Jon Marcaide, investigador principal del grupo de Radioastronomía, por haberme proporcionado la posibilidad de haber hecho la tesis, así como por sus comentarios y consejos para que las cosas siempre fueran a mejor. Gracias también a aquéllos que estaban cuando yo empecé pero que ya se fueron. Gracias a Eduardo Ros por haberme enseñado tanto sobre Radioastronomía y sobre la vida en general, por haberme abierto las puertas en el Max Planck Institute für Radioastronomie en Bonn, por su eficiencia, por su disponibilidad y por haberme transmitido la idea de que nuestro trabajo puede ser realmente una tarea apasionante. Gracias a Belén Arroyo, por tantas y tantas horas de conversaciones en el despacho, por todas las risas y por haber tenido siempre un momento para escucharme cuando lo he necesitado. Gracias a Iván Martí-Vidal por haberme acogido en el Onsala Space Observatory y por toda su ayuda y colaboración, tanto científica como personal. Y gracias también a Miguel Ángel Pérez-Torres, por su eficacia a la hora de trabajar, por sus consejos y por haberme transmitido una pequeña parte de todo lo que sabe. Fuera del grupo de Radioastronomía, pero dentro del Departamento de Astronomía y Astrofísica, también quiero agradecer el trabajo y apoyo de muchos compañeros. Aunque viii más que compañeros, son amigos. Gracias a Álex, Nico Sanchis, Nico De Brie, Jose, Vassili, Tomek, Neus, Héctor y Jesús. Gracias por todas las horas de vuestro tiempo que me habéis dedicado cuando os he buscado toda estresada. Gracias por todas las comidas, las cenas, los cafés, los juegos competitivos y las risas. Todo eso me ha dado fuerzas día tras día para poder continuar. Y gracias también a todos los miemb...

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Chromospheric Activity and Orbital Solution of Six New Late-type Spectroscopic Binary Systems

Cited by 22 publications

References 6 publications

A High-Precision Near-Infrared Survey for Radial Velocity Variable Low-Mass Stars Using Cshell and a Methane Gas Cell

A High-Precision Near-Infrared Survey for Radial Velocity Variable Low-Mass Stars Using Cshell and a Methane Gas Cell

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

Radio Emission from Binary Stars in the AB Doradus Moving Group

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