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http://inaoe.repositorioinstitucional.mx/jspui/handle/1009/2244| α Centauri A in the far infrared*: First measurement of the temperature minimum of a star other than the Sun | |
| Carlos del Burgo Díaz | |
| Acceso Abierto | |
| Atribución-NoComercial-SinDerivadas | |
| Stars: individual: αCen Stars: atmospheres Stars: chromospheres Circumstellar matter Infrared: stars Submillimeter: stars | |
| Context. Chromospheres and coronae are common phenomena on solar-type stars. Understanding the energy transfer to these heatedatmospheric layers requires direct access to the relevant empirical data. Study of these structures has, by and large, been limited to theSun thus far. Aims. The region of the temperature reversal can be directly observed only in the far infrared and submillimetre spectral regime. Weaim at determining the characteristics of the atmosphere in the region of the temperature minimum of the solar sister star α Cen A. Asa bonus this will also provide a detailed mapping of the spectral energy distribution, i.e. knowledge that is crucial when searching forfaint, Kuiper belt-like dust emission around other stars. Methods. For the nearby binary system α Cen, stellar parameters are known with high accuracy from measurements. For the basicmodel parameters Teff, log g and [Fe/H], we interpolate stellar model atmospheres in the grid of Gaia/PHOENIX and compute the corresponding model for the G2V star α Cen A. Comparison with photometric measurements shows excellent agreement between observed photospheric data in the optical and infrared. For longer wavelengths, the modelled spectral energy distribution is compared to Spitzer-MIPS, Herschel-PACS, Herschel-SPIRE, and APEX-LABOCA photometry. A specifically tailored Uppsala model based on the MARCS code and extending further in wavelength is used to gauge the emission characteristics of α CenA in the far infared. Results. Similar to the Sun, the far infrared (FIR) emission of α CenA originates in the minimum temperature region above the stellar photosphere in the visible. However, in comparison with the solar case, the FIR photosphere of α CenA appears marginally cooler, Tmin~T160μm = 3920±375 K. Beyond the minimum near 160 μm, the brightness temperatures increase, and this radiation very likely originates in warmer regions of the chromosphere of α Cen A. Conclusions. To the best of our knowledge, this is the first time a temperature minimum has been directly measured on a main-sequencestar other than the Sun. | |
| Astronomy & Astrophysics | |
| 2013 | |
| Artículo | |
| Inglés | |
| Estudiantes Investigadores Público en general | |
| Liseau, R., et al., (2013), α Centauri A in the far infrared*: First measurement of the temperature minimum of a star other than the Sun, Astronomy & Astrophysics, Vol. 549(L7):1-5 | |
| ASTRONOMÍA Y ASTROFÍSICA | |
| Versión aceptada | |
| acceptedVersion - Versión aceptada | |
| Aparece en las colecciones: | Artículos de Astrofísica |
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