Results 1 to 10 of about 59,534 (217)

Spectroscopy of Southern Active Stars [PDF]

International Astronomical Union Colloquium, 1991
AbstractHα and HeI D3 lines were observed in five active cool stars over their relatively short rotation periods. Three of the stars (AB Dor, Rstl37B, HD82558) are in the pre main sequence phase (as deduced from their lithium abundances), while two are post main sequence FK Comae type stars (HD32918 and BD-223467) (Vilhu et al., 1991).
O. Vilhu, B. Gustafsson, F. M. Walter
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Metallicities and activities of southern stars [PDF]

Astronomy & Astrophysics, 2008
We present the results from high-resolution spectroscopic measurements to determine metallicities and activities of bright stars in the southern hemisphere. We have measured the iron abundances ([Fe/H]) and chromospheric emission indices (logR'HK) of 353 solar-type stars with V=7.5-9.5.
Jenkins, J. S., Jones, H. R. A., Pavlenko, Y., Pinfield, D. J., Barnes, J. R., Lyubchik, Y.   +5 more
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Flare Activity Among Nearby Stars [PDF]

International Astronomical Union Colloquium, 1995
I selected the common objects from our Data Base on 234 UV Cet Flare Stars and Related Objects and the Third Catalogue of Nearby Stars by Gliese & Jahreiss (CNS-3). It is found that manifestation of flare activity (FA) (flares in any spectral region or photometric variability caused by spots) is observed on 143 flare stars (FS) out of the 3803 CNS ...
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Seismology of active stars [PDF]

Astronomische Nachrichten, 2012
AbstractIn this review we will discuss the current standing and open questions of seismology in active stars. With the longer photometric time series data that are, and will become, available from space‐missions such asKeplerwe foresee significant progress in our understanding of stellar internal structures and processes, including interactions between
Hekker, S., García, R.A.
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Planets Around Active Stars

, 2008
4 pages, 5 figures, to appear in the Proceedings of the ESO Workshop "Precision Spectroscopy in Astrophysics", eds. L. Pasquini, M. Romaniello, N.C.
Setiwan, J., Weise, P., Henning, T., Hatzes, A., Pasquini, L., da Silva, L., Girardi, L., von der Lühe, O., Döllinger, M., Weiss, A., Biazzo, K.   +10 more
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An activity catalogue of southern stars [PDF]

Monthly Notices of the Royal Astronomical Society, 2006
We have acquired high-resolution echelle spectra of 225 F6-M5 type stars in the southern hemisphere. The stars are targets or candidates to be targets for the Anglo-Australian Planet Search. CaII HK line cores were used to derive activity indices for all of these objects. The indices were converted to the Mt.
Jenkins, J. S., Jones, H. R. A., Tinney, C. G., Butler, R. P., McCarthy, C., Marcy, G. W., Pinfield, D. J., Carter, B. D., Penny, A. J.   +8 more
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The glitch activity of neutron stars [PDF]

Astronomy & Astrophysics, 2017
We present a statistical study of the glitch population and the behaviour of the glitch activity across the known population of neutron stars. An unbiased glitch database was put together based on systematic searches of radio timing data of 898 rotation-powered pulsars obtained with the Jodrell Bank and Parkes observatories.
J. R. Fuentes, C. M. Espinoza, A. Reisenegger, B. Shaw, B. W. Stappers, A. G. Lyne   +5 more
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Activity in F stars

The Astrophysical Journal, 1986
Measurements of He I 5876 A and IUE measurements of chromospheric and transition region lines in a large sample of F-type stars are presented. The data show that activity is detectable in nearly all early F-type stars and differs in several of its characteristics from that typically seen in cooler stars with slow rotation and fully developed convective
Sidney C. Wolff, Theodore Simon, Ann M. Boesgaard   +2 more
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Magnetic activities on young stars [PDF]

Earth, Planets and Space, 2014
Almost all young stellar objects (YSOs) are now known to emit X-rays driven by the magnetic activity. The solar-type dynamo is the plausible mechanism to generate the magnetic fields, but it does not work properly on protostars or intermediate-mass YSOs due to the difference of their stellar inner structure.
Hamaguchi, Kenji, Tsuboi, Yohko, Imanishi, Kensuke, Koyama, Katsuji   +3 more
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Active OB Stars - an introduction [PDF]

Proceedings of the International Astronomical Union, 2010
AbstractIdentifying seven activities and activity-carrying properties and nine classes of Active OB Stars, the OB Star Activity Matrix is constructed to map the parameter space. On its basis, the occurrence and appearance of the main activities are described as a function of stellar class.
Dietrich Baade, Thomas Rivinius, Stanislas Štefl, Christophe Martayan   +3 more
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