1,374 research outputs found
Periodic points of latitudinal maps of the m-dimensional sphere
Let f be a smooth self-map of the m-dimensional sphere Sm. Under the assumption that f preserves latitudinal foliations with the fibres S1, we estimate from below the number of fixed points of the iterates of f. The paper generalizes the results obtained by Pugh and Shub and by Misiurewicz
The PSU/TCfA Search for Planets around Evolved Stars. Stellar parameters and activity indicators of targets
The main objective of the Penn State/Torun Centre for Astronomy Search for
Planets around Evolved Stars is the detection of planetary systems around
massive, evolved stars. We are also interested in the evolution of these
systems on stellar evolution timescales. In this paper we present our approach
to determine the basic physical parameters of our targets GK-giants. We also
discuss the stellar activity indicators used in our survey: line bisector and
curvature, and Halpha variability.Comment: 5 pages, to appear in ,,Exoplanets. Detection, Formation & Dynamics''
IAU Symposium 249, Cambridge University Press, 200
Precise radial velocities of giant stars IX. HD 59686 Ab: a massive circumstellar planet orbiting a giant star in a ~13.6 au eccentric binary system
Context: For over 12 yr, we have carried out a precise radial velocity survey
of a sample of 373 G and K giant stars using the Hamilton \'Echelle
Spectrograph at Lick Observatory. There are, among others, a number of multiple
planetary systems in our sample as well as several planetary candidates in
stellar binaries. Aims: We aim at detecting and characterizing
substellar+stellar companions to the giant star HD 59686 A (HR 2877, HIP
36616). Methods: We obtained high precision radial velocity (RV) measurements
of the star HD 59686 A. By fitting a Keplerian model to the periodic changes in
the RVs, we can assess the nature of companions in the system. In order to
discriminate between RV variations due to non-radial pulsation or stellar spots
we used infrared RVs taken with the CRIRES spectrograph at the Very Large
Telescope. Additionally, to further characterize the system, we obtain
high-resolution images with LMIRCam at the Large Binocular Telescope. Results:
We report the likely discovery of a giant planet with a mass of orbiting at
au from the giant star HD 59686 A. Besides the planetary signal, we discover an
eccentric () binary companion with a mass of
orbiting at a semi-major axis
of just au. Conclusions: The existence of the
planet HD 59686 Ab in a tight eccentric binary system severely challenges
standard giant planet formation theories and requires substantial improvements
to such theories in tight binaries. Otherwise, alternative planet formation
scenarios such as second generation planets or dynamical interactions in an
early phase of the system's lifetime should be seriously considered in order to
better understand the origin of this enigmatic planet.Comment: 14 pages, 11 figures, 2 tables. Accepted for publication in A&A.
Updated version to match the published pape
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