Ref Arxiv: 1111.5515
DOI: 10.1088/1742-6596/328/1/012012
Ref. & Cit.: NASA ADS
12 citations
Abstract:

Convection plays an essential role in the emerging intensity for many stars that will be observed by Gaia. Convective-related surface structures affect the shape, shift, and asymmetry of absorption lines, the phocentric and photometric variability causing bias in Gaia measurements. Regarding the importance of Gaia mission and its goals, it is mandatory to have the best models of the observed stars. 3D time-dependent hydrodynamical simulations of surface convection are crucial to model the photosphere of late type stars in a very realistic way. These simulations are an important tool to correct the radial velocities and better estimates the parallaxes and photometric variability.

Comments: Accepted for publication in the Journal of Physics, Conference Series. Proceedings of the GREAT-ESF Workshop on "Stellar Atmospheres in the Gaia Era."

Ref HAL: hal-00722124_v1
DOI: 10.1051/0004-6361/201117450
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24 citations

DOI: 10.1016/j.jqsrt.2010.10.012
14 citations
Abstract:

Recently, a high temperature source has been used to produce high temperature emission spectra of acetylene in the 3 μm spectral range, under Doppler limited resolution, and the complete spectral assignment has been performed using a global rovibrational Hamiltonian [Amyay B, Robert S, Herman M, Fayt A, Raghavendra B, Moudens A et al. Vibration–rotation pattern in acetylene (II): Introduction to Coriolis coupling in the global model and analysis of emission spectra of hot acetylene around 3 μm. J Chem Phys 2009;131:114301]. The present investigation focuses on the relative emission line intensities which are observed to be affected. The strongest lines intensity may be considerably reduced for high column density acetylene samples, hence affecting the 3:1 ortho:para intensity ratio. A radiative model is developed to take into account the effects generated by the strong opacity of the acetylene samples including self-absorption and absorption of the radiation emitted by the hot environment. The model is used to extract the absolute concentration of the high temperature acetylene samples from the observed relative spectral intensities. The relevance of the procedure for infrared remote sensing in high temperature astrophysical environments, such as circumstellar envelopes of cool carbon rich evolved stars, is discussed.

Ref HAL: hal-00727306_v1
Ref Arxiv: 1204.5193
DOI: 10.1051/0004-6361/201118331
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
153 citations

DOI: 10.1139/p10-122
Abstract:

The abundance of heavy r-elements may provide a better understanding of the r-process, and the determination of several reference r-elements should allow a better determination of a star's age. The space UV region (λ < 3000 Å) presents a large number of lines of the heavy elements, and in the case of some elements, such as Bi, Pt, Au, detectable lines are not available elsewhere. The extreme “r-process star” CS 31082–001 ([Fe/H] = –2.9) was observed in the space UV to determine abundances of the heaviest stable elements, using STIS on board Hubble Space Telescope.

Ref HAL: hal-00672051_v1
DOI: 10.1051/epjconf/20111802002
Exporter : BibTex | endNote

Ref HAL: hal-00671949_v1
Ref Arxiv: 1102.1969
DOI: 10.1051/0004-6361/201015997
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
50 citations