EChO spectra and stellar activity II. The case of dM stars

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• 作者：Gaetano Scandariato ; Giuseppina Micela
• 关键词：Exoplanets ; Stellar Atmosphere ; Stellar activity ; EChO
• 刊名：Experimental Astronomy
• 出版年：2015
• 出版时间：December 2015
• 年：2015
• 卷：40
• 期：2-3
• 页码：711-722
• 全文大小：1,223 KB
• 参考文献：1.Allard, F., Homeier, D., Freytag, B.: Model atmospheres from very low mass stars to brown Dwarfs. In: 16th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun, vol. 448, pp. 91 (2011)
  2.Ballerini, P., Micela, G., Lanza, A. F., Pagano, I.: Multiwavelength flux variations induced by stellar magnetic activity: effects on planetary transits. Astron. Astrophys. 539, A140 (2012)CrossRef ADS
  3.Berdyugina, S. V.: Starspots: A key to the Stellar dynamo. Living Rev. Solar Phys. 2, 8 (2005)CrossRef ADS
  4.Bochanski, J. J., West, A. A., Hawley, S. L., Covey, K. R.: Low-mass Dwarf template spectra from the sloan digital sky survey. Astron. J. 133, 531 (2007)CrossRef ADS
  5.Cincunegui, C., Díaz, R. F., Mauas, P. J. D.: H α and the Ca II H and K lines as activity proxies for late-type stars. Astron Astrophys. 469, 309 (2007)CrossRef ADS
  6.Gomes da Silva, J., Santos, N. C., Bonfils, X., et al.: Long-term magnetic activity of a sample of M-dwarf stars from the HARPS program. I. Comparison of activity indices. Astron. Astrophys. 534, A30 (2011)CrossRef ADS
  7.Jackson, R. J., Jeffries, R. D.: On the relationship between the size and surface coverage of starspots on magnetically active low-mass stars. Monthly Not. Royal Astron. Soc. 431, 1883 (2013)CrossRef ADS
  8.Martínez-Arnáiz, R., López-Santiago, J., Crespo-Chacón, I., Montes, D.: Effect of magnetic activity saturation in chromospheric flux-flux relationships. Monthly Not. Royal Astron. Soc. 414, 2629 (2011)CrossRef ADS
  9.Micela, G.: This Volume of Experimental Astronomy
  10.Reid, I. N., Hawley, S. L.: New light on dark stars red Dwarfs, low-mass stars, brown stars. Praxis Publishing Ltd (2005)
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  12.Stelzer, B., Frasca, A., Alcalá, J. M., et al.: X-shooter spectroscopy of young stellar objects. III. Photospheric and chromospheric properties of class III objects. Astron. Astrophys. 558, A141 (2013)CrossRef ADS
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  14.Tinetti, G.: This volume of experimental astronomy
  15.West, A. A., Morgan, D. P., Bochanski, J. J., et al.: The Sloan digital sky survey data release 7 spectroscopic M Dwarf catalog I. Data. Astron. J. 141, 97 (2011)CrossRef ADS
  16.York, D. G., Adelman, J., Anderson, J. E. Jr, et al.: The sloan digital sky survey: Technical summary. Astron. J. 120, 1579 (2000)CrossRef ADS
  
• 作者单位：Gaetano Scandariato (1) (2)
  Giuseppina Micela (1)
  
  1. INAF - Osservatorio Astronomico di Palermo “G. Vaiana”, P.za del Parlamento 1, Palermo, Italy
  2. INAF - Osservatorio Astrofisico di Catania, 95123, via S. Sofia, 78, Catania, Italy
  
• 刊物类别：Physics and Astronomy
• 刊物主题：Physics
  Astronomy
  Statistics for Engineering, Physics, Computer Science, Chemistry and Geosciences
  
• 出版者：Springer Netherlands
• ISSN：1572-9508

文摘

EChO is a dedicated mission to investigate exoplanetary atmospheres. When extracting the planetary signal, one has to take care of the variability of the hosting star, which introduces spectral distortion that can be mistaken as planetary signal. Magneticvariability has to be taken into account in particular for M stars. To this purpose, assuming a one spot dominant model for the stellar photosphere, we develop a mixed observational-theoretical tool to extract the spot’s parameters from the observed optical spectrum. This method relies on a robust library of spectral M templates, which we derive using the observed spectra of quiet M dwarfs in the SDSS database. Our procedure allows to correct the observed spectra for photospheric activity in most of the analyzed cases, reducing the spectral distortion down to the noise levels. Ongoing refinements of the template library and the algorithm will improve the efficiency of our algorithm. Keywords Exoplanets Stellar Atmosphere Stellar activity EChO