All Outputs (16)

Pre-main-sequence isochrones - III: The Cluster Collaboration isochrone server (2014)
Journal Article
Jeffries. (2014). Pre-main-sequence isochrones - III: The Cluster Collaboration isochrone server. Monthly Notices of the Royal Astronomical Society, 3496 - 3511. https://doi.org/10.1093/mnras/stu1944

We present an isochrone server for semi-empirical pre-main-sequence model isochrones in the following systems: Johnson–Cousins, Sloan Digital Sky Survey, Two-Micron All-Sky Survey, Isaac Newton Telescope (INT) Wide-Field Camera and INT Photometric Ha... Read More about Pre-main-sequence isochrones - III: The Cluster Collaboration isochrone server.

Using rotation, magnetic activity and lithium to estimate the ages of low mass stars (2014)
Journal Article
Jeffries, R. (2014). Using rotation, magnetic activity and lithium to estimate the ages of low mass stars. EAS Publications Series, 65, 289-325. https://doi.org/10.1051/eas/1465008

The rotation rate, level of magnetic activity and surface lithium abundance are age-dependent quantities in stars of about a solar mass and below. The physical reasons for the evolution of these phenomena are qualitatively understood, but accurate qu... Read More about Using rotation, magnetic activity and lithium to estimate the ages of low mass stars.

The Gaia-ESO Survey: The analysis of high-resolution UVES spectra of FGK-type stars (2014)
Journal Article
Smiljanic, R., Korn, A., Bergemann, M., Frasca, A., Magrini, L., Masseron, T., …Zaggia, S. (2014). The Gaia-ESO Survey: The analysis of high-resolution UVES spectra of FGK-type stars. Astronomy and Astrophysics, 570, Article A122. https://doi.org/10.1051/0004-6361/201423937

Context. The ongoing Gaia-ESO Public Spectroscopic Survey is using FLAMES at the VLT to obtain high-quality medium-resolution Giraffe spectra for about 105 stars and high-resolution UVES spectra for about 5000 stars. With UVES, the Survey has already... Read More about The Gaia-ESO Survey: The analysis of high-resolution UVES spectra of FGK-type stars.

The Gaia-ESO Survey: Metallicity of the Chamaeleon I star-forming region (2014)
Journal Article
Spina, L., Randich, S., Palla, F., Biazzo, K., Sacco, G. G., Alfaro, E. J., …Worley, C. C. (2014). The Gaia-ESO Survey: Metallicity of the Chamaeleon I star-forming region. Astronomy & Astrophysics, 568, A2. https://doi.org/10.1051/0004-6361/201424135

Context. Recent metallicity determinations in young open clusters and star-forming regions suggest that the latter may be characterized by a slightly lower metallicity than the Sun and older clusters in the solar vicinity. However, these results are... Read More about The Gaia-ESO Survey: Metallicity of the Chamaeleon I star-forming region.

The Gaia-ESO Survey: the first abundance determination of the pre-main-sequence cluster gamma Velorum (2014)
Journal Article
Spina, L., Randich, S., Palla, F., Sacco, G. G., Magrini, L., Franciosini, E., …Worley, C. (2014). The Gaia-ESO Survey: the first abundance determination of the pre-main-sequence cluster gamma Velorum. Astronomy & Astrophysics, 567, Article A55. https://doi.org/10.1051/0004-6361/201423527

Context. Knowledge of the abundance distribution of star forming regions and young clusters is critical to investigate a variety of issues, from triggered star formation and chemical enrichment by nearby supernova explosions to the ability to form pl... Read More about The Gaia-ESO Survey: the first abundance determination of the pre-main-sequence cluster gamma Velorum.

The Gaia-ESO Survey: the Galactic thick to thin disc transition (2014)
Journal Article
Recio-Blanco, A., de Laverny, P., Kordopatis, G., Helmi, A., Hill, V., Gilmore, G., …Maiorca, E. (2014). The Gaia-ESO Survey: the Galactic thick to thin disc transition. Astronomy & Astrophysics, 567, Article A5. https://doi.org/10.1051/0004-6361/201322944

Aims. The nature of the thick disc and its relation to the thin disc is presently an important subject of debate. In fact, the structural and chemo-dynamical transition between disc populations can be used as a test of the proposed models of Galactic... Read More about The Gaia-ESO Survey: the Galactic thick to thin disc transition.

The effect of star-spots on the ages of low-mass stars determined from the lithium depletion boundary (2014)
Journal Article
Jackson, R. J., & Jeffries, R. D. (2014). The effect of star-spots on the ages of low-mass stars determined from the lithium depletion boundary. Monthly Notices of the Royal Astronomical Society, 445(4), 2111-2123. https://doi.org/10.1093/mnras/stu2076

In a coeval group of low-mass stars, the luminosity of the sharp transition between stars that retain their initial lithium and those at slightly higher masses in which Li has been depleted by nuclear reactions, the lithium depletion boundary (LDB),... Read More about The effect of star-spots on the ages of low-mass stars determined from the lithium depletion boundary.

Gaia-ESO Survey: Empirical classification of VLT/Giraffe stellar spectra in the wavelength range 6440–6810 Å in theγVelorum cluster, and calibration of spectral indices (2014)
Journal Article
Damiani, F., Prisinzano, L., Micela, G., Randich, S., Gilmore, G., Drew, J. E., …Maiorca, E. (2014). Gaia-ESO Survey: Empirical classification of VLT/Giraffe stellar spectra in the wavelength range 6440–6810 Å in theγVelorum cluster, and calibration of spectral indices. Astronomy and Astrophysics, 566, A50. https://doi.org/10.1051/0004-6361/201323306

We present a study of spectral diagnostics available from optical spectra with R = 17 000 obtained with the VLT/Giraffe HR15n setup, using observations from the Gaia-ESO Survey, on the γ Vel young cluster, with the purpose of classifying these stars... Read More about Gaia-ESO Survey: Empirical classification of VLT/Giraffe stellar spectra in the wavelength range 6440–6810 Å in theγVelorum cluster, and calibration of spectral indices.

The Gaia-ESO Survey: processing FLAMES-UVES spectra (2014)
Journal Article
Sacco, G. G., Morbidelli, L., Franciosini, E., Maiorca, E., Randich, S., Modigliani, A., …Worley, C. (2014). The Gaia-ESO Survey: processing FLAMES-UVES spectra. Astronomy & Astrophysics, 565, A113. https://doi.org/10.1051/0004-6361/201423619

The Gaia-ESO Survey is a large public spectroscopic survey that aims to derive radial velocities and fundamental parameters of about 105 Milky Way stars in the field and in clusters. Observations are carried out with the multi-object optical spectrog... Read More about The Gaia-ESO Survey: processing FLAMES-UVES spectra.

The effect of starspots on the radii of low-mass pre-main-sequence stars (2014)
Journal Article
Jackson, R. J., & Jeffries, R. D. (2014). The effect of starspots on the radii of low-mass pre-main-sequence stars. Monthly Notices of the Royal Astronomical Society, 441(3), 2111-2123. https://doi.org/10.1093/mnras/stu651

A polytropic model is used to investigate the effects of dark photospheric spots on the evolution and radii of magnetically active, low-mass (M < 0.5 M⊙), pre-main-sequence (PMS) stars. Spots slow the contraction along Hayashi tracks and inflate the... Read More about The effect of starspots on the radii of low-mass pre-main-sequence stars.

The Gaia-ESO Survey: radial metallicity gradients and age-metallicity relation of stars in the Milky Way disk (2014)
Journal Article
Bergemann, M., Ruchti, G. R., Serenelli, A., Feltzing, S., Alves-Brito, A., Asplund, M., …Tautvaišienė, G. (2014). The Gaia-ESO Survey: radial metallicity gradients and age-metallicity relation of stars in the Milky Way disk. Astronomy & Astrophysics, 565, Article A89. https://doi.org/10.1051/0004-6361/201423456

We study the relationship between age, metallicity, and α-enhancement of FGK stars in the Galactic disk. The results are based upon the analysis of high-resolution UVES spectra from the Gaia-ESO large stellar survey. We explore the limitations of the... Read More about The Gaia-ESO Survey: radial metallicity gradients and age-metallicity relation of stars in the Milky Way disk.

AN ANOMALOUS EXTINCTION LAW IN THE Cep OB3b YOUNG CLUSTER: EVIDENCE FOR DUST PROCESSING DURING GAS DISPERSAL (2014)
Journal Article
Allen, T. S., Prchlik, J. J., Megeath, S. T., Gutermuth, R. A., Pipher, J. L., Naylor, T., & Jeffries, R. D. (2014). AN ANOMALOUS EXTINCTION LAW IN THE Cep OB3b YOUNG CLUSTER: EVIDENCE FOR DUST PROCESSING DURING GAS DISPERSAL. Astrophysical Journal, 786(2), 113. https://doi.org/10.1088/0004-637x/786/2/113

We determine the extinction law through Cep OB3b, a young cluster of 3000 stars undergoing gas dispersal. The extinction is measured toward 76 background K giants identified with MMT/Hectospec spectra. Color excess ratios were determined toward each... Read More about AN ANOMALOUS EXTINCTION LAW IN THE Cep OB3b YOUNG CLUSTER: EVIDENCE FOR DUST PROCESSING DURING GAS DISPERSAL.

Gaia-ESO Survey: Properties of the intermediate age open cluster NGC 4815 (2014)
Journal Article
Friel, E. D., Donati, P., Bragaglia, A., Jacobson, H. R., Magrini, L., Prisinzano, L., …Lind, K. (2014). Gaia-ESO Survey: Properties of the intermediate age open cluster NGC 4815. Astronomy & Astrophysics, 563, 1-10. https://doi.org/10.1051/0004-6361/201323215

Context. NGC 4815 is a populous ~500 Myr open cluster at Rgc ~ 7 kpc observed in the first six months of the Gaia-ESO Survey. Located in the inner Galactic disk, NGC 4815 is an important potential tracer of the abundance gradient, where relatively fe... Read More about Gaia-ESO Survey: Properties of the intermediate age open cluster NGC 4815.

The Gaia-ESO Survey: Kinematic structure in the Gamma Velorum cluster (2014)
Journal Article
Jeffries, R. D., Jackson, R. J., Cottaar, M., Koposov, S. E., Lanzafame, A. C., Meyer, M. R., …Maiorca, E. (2014). The Gaia-ESO Survey: Kinematic structure in the Gamma Velorum cluster. Astronomy & Astrophysics, 563, A94. https://doi.org/10.1051/0004-6361/201323288

Context. A key science goal of the Gaia-ESO survey (GES) at the VLT is to use the kinematics of low-mass stars in young clusters and star forming regions to probe their dynamical histories and how they populate the field as they become unbound. The c... Read More about The Gaia-ESO Survey: Kinematic structure in the Gamma Velorum cluster.

Strong biases in estimating the time dependence of mass accretion rates in young stars (2014)
Journal Article
Da Rio, N., Jeffries, R. D., Manara, C. F., & Robberto, M. (2014). Strong biases in estimating the time dependence of mass accretion rates in young stars. Monthly Notices of the Royal Astronomical Society, 439(4), 3308-3328. https://doi.org/10.1093/mnras/stu149

The temporal decay of mass accretion in young stars is a fundamental tracer of the early evolution of circumstellar discs. Through population syntheses, we study how correlated uncertainties between the estimated parameters of young stars (luminosity... Read More about Strong biases in estimating the time dependence of mass accretion rates in young stars.

The Gaia-ESO Survey: Abundance ratios in the inner-disk open clusters Trumpler 20, NGC 4815, NGC 6705 (2014)
Journal Article
Magrini, L., Randich, S., Romano, D., Friel, E., Bragaglia, A., Smiljanic, R., …Worley, C. (2014). The Gaia-ESO Survey: Abundance ratios in the inner-disk open clusters Trumpler 20, NGC 4815, NGC 6705. Astronomy & Astrophysics, 563, A44. https://doi.org/10.1051/0004-6361/201322977

Context. Open clusters are key tools to study the spatialdistribution of abundances in the disk and their evolution with time. Aims. Using the first release of stellar parameters and abundances of the Gaia-ESO Survey, we analyse the chemical prope... Read More about The Gaia-ESO Survey: Abundance ratios in the inner-disk open clusters Trumpler 20, NGC 4815, NGC 6705.