TY - JOUR
T1 - Tracking Advanced Planetary Systems (TAPAS) with HARPS-N
T2 - II. Super Li-rich giant HD 107028
AU - Adamów, M.
AU - Niedzielski, A.
AU - Villaver, E.
AU - Wolszczan, A.
AU - Kowalik, K.
AU - Nowak, G.
AU - Adamczyk, M.
AU - Deka-Szymankiewicz, B.
N1 - Funding Information:
We thank the HET and IAC resident astronomers and telescope operators for their support. We would like to thank Dr. Sergio Simon Diaz from IAC for obtaining the Mercator/Hermes spectrum used in this work. We also thank Dr. Christopher Sneden for comments that greatly improved the manuscript. M.A. acknowledges the Mobility+III fellowship from the Polish Ministry of Science and Higher Education. M.A., A.N., B.D. and MiA were supported by the Polish National Science Centre grant No. UMO-2012/07/B/ST9/04415. E.V. acknowledges support from the Spanish Ministerio de Economía y Competitividad under grant AYA2013-45347P. K.K. was funded in part by the Gordon and Betty Moore Foundation’s Data-Driven Discovery Initiative through Grant GBMF4561. This research was supported in part by PL-Grid Infrastructure. The HET is a joint project of the University of Texas at Austin, the Pennsylvania State University, Stanford University, Ludwig- Maximilians-Universität München, and Georg-August-Universität Göttingen. The HET is named in honor of its principal benefactors, William P. Hobby and Robert E. Eberly. The Center for Exoplanets and Habitable Worlds is supported by the Pennsylvania State University, the Eberly College of Science, and the Pennsylvania Space Grant Consortium. This work is based on observations obtained with the HERMES spectrograph, which is supported by the Fund for Scientific Research of Flanders (FWO), Belgium, the Research Council of K.U.Leuven, Belgium, the Fonds National de la Recherche Scientifique (F.R.S.-FNRS), Belgium, the Royal Observatory of Belgium, the Observatoire de Genève, Switzerland and the Thüringer Landessternwarte Tautenburg, Germany. This work makes use of Astropy, a community-developed core Python package for Astronomy, as well as SciPy and NumPy.
Publisher Copyright:
© ESO, 2015.
PY - 2015/9/1
Y1 - 2015/9/1
N2 - Context. Lithium-rich giant stars are rare objects. For some of them, Li enrichment exceeds the abundance of this element found in solar system meteorites, suggesting that these stars have gone through a Li enhancement process. Aims. We identified a Li-rich giant HD 107028 with A(Li) > 3.3 in a sample of evolved stars observed within the PennState Toruń Planet Search. In this work we study different enhancement scenarios and we try to identify the one responsible for Li enrichment in HD 107028. Methods. We collected high-resolution spectra with three different instruments, covering different spectral ranges. We determined stellar parameters and abundances of selected elements with both equivalent width measurements and analysis, and spectral synthesis. We also collected multi-epoch high-precision radial velocities in an attempt to detect a companion. Results. Collected data show that HD 107028 is a star at the base of the red giant branch (RGB). Except for high Li abundance, we have not identified any other anomalies in its chemical composition, and there is no indication of a low-mass or stellar companion. We exclude Li production at the luminosity function bump on the RGB as the effective temperature and luminosity suggest that the evolutionary state is much earlier than the RGB bump. We also cannot confirm the Li enhancement by contamination as we do not observe any anomalies that are associated with this scenario. Conclusions. After evaluating various scenarios of Li enhancement we conclude that the Li-overabundance of HD 107028 originates from main-sequence evolution, and may be caused by diffusion processes.
AB - Context. Lithium-rich giant stars are rare objects. For some of them, Li enrichment exceeds the abundance of this element found in solar system meteorites, suggesting that these stars have gone through a Li enhancement process. Aims. We identified a Li-rich giant HD 107028 with A(Li) > 3.3 in a sample of evolved stars observed within the PennState Toruń Planet Search. In this work we study different enhancement scenarios and we try to identify the one responsible for Li enrichment in HD 107028. Methods. We collected high-resolution spectra with three different instruments, covering different spectral ranges. We determined stellar parameters and abundances of selected elements with both equivalent width measurements and analysis, and spectral synthesis. We also collected multi-epoch high-precision radial velocities in an attempt to detect a companion. Results. Collected data show that HD 107028 is a star at the base of the red giant branch (RGB). Except for high Li abundance, we have not identified any other anomalies in its chemical composition, and there is no indication of a low-mass or stellar companion. We exclude Li production at the luminosity function bump on the RGB as the effective temperature and luminosity suggest that the evolutionary state is much earlier than the RGB bump. We also cannot confirm the Li enhancement by contamination as we do not observe any anomalies that are associated with this scenario. Conclusions. After evaluating various scenarios of Li enhancement we conclude that the Li-overabundance of HD 107028 originates from main-sequence evolution, and may be caused by diffusion processes.
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U2 - 10.1051/0004-6361/201526582
DO - 10.1051/0004-6361/201526582
M3 - Article
AN - SCOPUS:84941365070
VL - 581
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
SN - 0004-6361
M1 - A94
ER -