Zobrazeno 1 - 10
of 146
pro vyhledávání: '"Koesterke, L."'
The use of 3D hydrodynamical simulations of stellar surface convection for model atmospheres is computationally expensive. Although these models have been available for quite some time, their use is limited because of the lack of extensive grids of s
Externí odkaz:
http://arxiv.org/abs/2202.12086
Autor:
Zamora, O., Garcia-Hernandez, D. A., Prieto, C. Allende, Carrera, R., Koesterke, L., Edvardsson, B., Castelli, F., Plez, B., Bizyaev, D., Cunha, K., Perez, A. E. Garcia, Gustafsson, B., Holtzman, J. A., Lawler, J. E., Majewski, S. R., Manchado, A., Meszaros, Sz., Shane, N., Shetrone, M., Smith, V. V., Zasowski, G.
The Sloan Digital Sky Survey--III (SDSS--III) Apache Point Observatory Galactic Evolution Experiment (APOGEE) has obtained high resolution (R $\sim$ 22,500), high signal-to-noise ratio ($>$ 100) spectra in the H$-$band ($\sim$1.5$-$1.7 $\mu$m) for ab
Externí odkaz:
http://arxiv.org/abs/1502.05237
Autor:
Mészáros, Sz., Holtzman, J., Pérez, A. E. García, Prieto, C. Allende, Schiavon, R. P., Basu, S., Bizyaev, D., Chaplin, W. J., Chojnowski, S. D., Cunha, K., Elsworth, Y., Epstein, C., Frinchaboy, P. M., García, R. A., Hearty, F. R., Hekker, S., Johnson, J. A., Kallinger, T., Koesterke, L., Majewski, S. R., Martell, S. L., Nidever, D., Pinsonneault, M. H., O'Connell, J., Shetrone, M., Smith, V. V., Wilson, J. C., Zasowski, G.
The SDSS-III Apache Point Observatory Galactic Evolution Experiment (APOGEE) is a three year survey that is collecting 100,000 high-resolution spectra in the near-IR across multiple Galactic populations. To derive stellar parameters and chemical comp
Externí odkaz:
http://arxiv.org/abs/1308.6617
To derive space velocities of stars along the line of sight from wavelength shifts in stellar spectra requires accounting for a number of second-order effects. For most stars, gravitational redshifts, convective blueshifts, and transverse stellar mot
Externí odkaz:
http://arxiv.org/abs/1301.3703
For late-type non-active stars, gravitational redshifts and convective blueshifts are the main source of biases in the determination of radial velocities. If ignored, these effects can introduce systematic errors of the order of ~ 0.5 km/s. We demons
Externí odkaz:
http://arxiv.org/abs/0909.0470
We have obtained ultra-high quality spectra (R=180,000; S/N>300) with unprecedented wavelength coverage (4400 to 7400 A) for a number of stars covering most of the HR diagram in order to test the predictions of models of stellar surface convection. L
Externí odkaz:
http://arxiv.org/abs/0908.4571
We construct a 3D radiative-hydrodynamic model atmosphere of parameters Teff = 4820 K, log g = 4.5, and solar chemical composition. The theoretical line profiles computed with this model are asymmetric, with their bisectors having a characteristic C-
Externí odkaz:
http://arxiv.org/abs/0905.3101
A possible origin of the iron-deficiency in PG1159 stars could be neutron captures on Fe nuclei. A nickel overabundance would corroborate this idea. Consequently we are looking for nickel lines in PG1159 stars. Prime targets are relatively cool objec
Externí odkaz:
http://arxiv.org/abs/0803.0066
We examine closely the solar Center-to-Limb variation of continua and lines and compare observations with predictions from both a 3-D hydrodynamic simulation of the solar surface (provided by M. Asplund and collaborators) and 1-D model atmospheres. I
Externí odkaz:
http://arxiv.org/abs/0802.2177
Autor:
Lee, Y. S., Beers, T. C., Sivarani, T., Johnson, J. A., An, D., Wilhelm, R., Prieto, C. Allende, Koesterke, L., Fiorentin, P. Re, Bailer-Jones, C. A. L., Norris, J. E., Yanny, B., Rockosi, C. M., Newberg, H. J., Cudworth, K. M., Pan, K.
Publikováno v:
Astron.J.136:2050-2069,2008
We validate the performance and accuracy of the current SEGUE (Sloan Extension for Galactic Understanding and Exploration) Stellar Parameter Pipeline (SSPP), which determines stellar atmospheric parameters (effective temperature, surface gravity, and
Externí odkaz:
http://arxiv.org/abs/0710.5778