Evolution of the chromospheric and coronal activity of intermediate mass stars |
| |
| Institution: | 1. European Southern Observatory, Karl Schwarzschild Straße 2, Garching 85748, Germany;2. Department of Physics, University of Warwick, Coventry CV4 7AL, UK;3. Departamento de Astronomia, Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo (IAG/USP), Rua do Matão 1226, 05508-900 São Paulo, Brazil;4. European Southern Observatory, Alonso de Córdova 3107, Casilla 19001, Santiago, Chile;5. Centro de Estudios de Física del Cosmos de Aragón (CEFCA), Unidad Asociada al CSIC, Plaza San Juan 1, Planta-3, E-44001 Teruel, Spain;6. Departament de Física, Universitat Politécnica de Catalunya, c/Esteve Terrades 5, E-08860 Castelldefels, Spain;1. Key Laboratory of Space Astronomy and Technology, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China;2. School of Astronomy and Space Sciences, University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, China |
| |
| Abstract: | Recent ultraviolet and X-ray observations pertaining to the outer atmospheric structure of intermediate mass (4–6 M0) stars and the evolution of their structure are presented. A distance-limited (d ≤ 200 pc) IUE ultraviolet survey of early K bright giants shows that C IV emission commonly is present. These stars are almost evenly split between stars showing hybrid-chromospheric and coronal outer atmospheric structures. EXOSAT observations have been obtained for three hybrid stars, of which only α TrA, the nearest, is detected. The temperature of the emitting plasma is likely to be ∼106K. Observations of six K II stars made with the Einstein satellite show no detections. The general conclusion from the available X-ray data is that early K bright giants are not strong X-ray sources. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
