Sentences with phrase «of isochrones»

With a metallicity around 1.12 Sol's and higher chromospheric activity than Sol the star appears to be 2.5 + / -1.8 billion years old — probably younger than Sol's 4.6 billion years (press release), and one analysis of isochrones suggests that the star may only be 2.0 billion years old (Crepp et al, 2012); and Guinan et al, 1999).

Moreover, based on one analysis of isochrones, the star may only be 1.7 billion years old (Guinan et al, 1999).

Not exact matches

Using this data, the researchers created an isochrone map — a map of lines connecting locations where a given spike arrived at the same time.

Examining each Kepler system individually considering multiple avenues (isochrone mapping, contrast curves, probability of being bound), we suggest two cases for which the techniques most likely agree in their companion detections (detect the same companion star).

Although our revised temperatures are generally consistent with those reported in the Ecliptic Plane Input Catalog (EPIC), our revised stellar radii are typically 0.13 solar radii (39 %) larger than the EPIC values, which were based on model isochrones that have been shown to underestimate the radii of cool dwarfs.

61 Virginis is a yellow - orange main sequence dwarf of spectral and luminosity type G5 - 6 V, with about 92 to 96 percent of Sol's mass (95 percent using the isochrone mass estimate of Valenti and Fischer, 2005; and NASA Star and Exoplanet Database, based on David F. Gray, 1992), 94 to 98 percent of its diameter (96 percent for Valenti and Fischer, 2005; Johnson and Wright, 1983, page 677; and NASA Star and Exoplanet Database, derived from the exponential formula of Kenneth R. Lang, 1980), and around 78 percent of its visual luminosity and nearly 81 percent of its theoretical bolometric luminosity, with infrared radiation (Sousa et al, 2008; Valenti and Fischer, 2005; NASA Star and Exoplanet Database, based on Kenneth R. Lang, 1980).

We prepared datasets that allowed us to study the improvement of distance and age estimates with the inclusion of TGAS and Gaia end - of - mission parallax precisions in isochrone fitting.

We use spectroscopic data from a variety of large surveys combined with infra - red photometry from 2MASS and AllWISE and compare these in a Bayesian manner with PARSEC isochrones to derive probability density functions (PDFs) for stellar masses, ages and distances.

Considering two different cluster ages (100 and 150 Myr), we selected cluster member candidates on the basis of their location in the (I,I - z) CMD relative to the isochrones, and estimated the contamination by foreground late - type field dwarfs using statistical arguments, infrared photometry and low - resolution optical spectroscopy.

The catalog is based on a compilation of literature values for atmospheric properties (temperature, surface gravity, and metallicity) derived from different observational techniques (photometry, spectroscopy, asteroseismology, and exoplanet transits), which were then homogeneously fitted to a grid of Dartmouth stellar isochrones.

We demonstrate that we will be able to improve our distance estimates for about one third of stars in spectroscopic surveys and to decrease log (age) uncertainties by about a factor of two for over 80 % of stars as compared to the uncertainties obtained without parallax priors using Gaia end - of - mission parallaxes consistently with spectrophotometry in isochrone fitting.