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Full-Text Articles in Physical Sciences and Mathematics
Photospheric Temperature Measurements In Young Main Sequence Stars, Katia Biazzo, Antonio Frasca, Gregory W. Henry, S. Catalano, Ettore Marilli
Photospheric Temperature Measurements In Young Main Sequence Stars, Katia Biazzo, Antonio Frasca, Gregory W. Henry, S. Catalano, Ettore Marilli
Information Systems and Engineering Management Research Publications
As part of our program to study stellar photospheric and chromospheric activity, we have examined several young solar type stars with activity levels intermediate between the Sun and the very active RS CVn binaries. We have analysed contemporaneous spectroscopic data obtained at Catania Observatory (Serra La Nave station, Mt. Etna) and photometric data acquired in the Stromgren bands with an automatic photometric telescope (APT) at Fairborn Observatory (Arizona, USA). Surface inhomogeneities have been detected from the rotational modulation of stellar brightness as well as from the modulation of several photospheric line-depth ratios (LDRs). The presence of chromospheric plage-like regions has …
Why Do Some Spotted Stars Become Bluer As They Become Fainter?, Vidar Aarum-Ulvås, Gregory W. Henry
Why Do Some Spotted Stars Become Bluer As They Become Fainter?, Vidar Aarum-Ulvås, Gregory W. Henry
Information Systems and Engineering Management Research Publications
Chromospherically active, spotted stars generally become redder as well as fainter when large starspots rotate into view on the stellar disc. However, the RS CVn system UX Ari (a triple-lined system), becomes bluer as it gets fainter. One possible explanation is that hot, bright facular regions accompany the cool, dark photospheric spots of the active component. The bluer flux of the hotter, inactive component does not appear to be sufficient to explain the observed behaviour. We have begun a search for additional chromospherically active stars with a similar relation between colour and brightness, to investigate whether these relations can be …
Searching For Planets In The Hyades. Iii. The Quest For Short-Period Planets, Diane B. Paulson, Steven H. Saar, William D. Cochran, Gregory W. Henry
Searching For Planets In The Hyades. Iii. The Quest For Short-Period Planets, Diane B. Paulson, Steven H. Saar, William D. Cochran, Gregory W. Henry
Information Systems and Engineering Management Research Publications
We have been using the Keck I High Resolution Spectrograph to search for planetary companions in the Hyades cluster. We selected four stars from this sample that showed significant radial velocity variability on short timescales to search for short-period planetary companions. The radial velocities of these four stars were monitored regularly with the Hobby-Eberly Telescope for approximately 2 months, while sparse data were also taken over ∼4 months: we also obtained near-simultaneous photometric observations with one of the automatic photoelectric telescopes at Fairborn Observatory. For three of the stars, we detect photometric variability with the same period present in the …