English
Related papers

Related papers: The Cool Giant HD 77361 - A Super Li-Rich Star

200 papers

Results from high resolution spectroscopic analysis of HD 77361 are reported. The LTE analysis shows that HD 77361 is a K giant of atmospheric parameters: Teff = 4580 +/- 75 K, log$g$ = 2.5 +/- 0.1, and \xi_{t} = 1.40 +/-0.5 km/s. We found…

Solar and Stellar Astrophysics · Physics 2009-08-20 Bharat Kumar Yerra , Bacham Eswar Reddy

In this work, the helium-enhancement (He-enhancement) in the lithium-rich (Li-rich) K-giant HD 77361 is investigated using the strengths of the MgH band and the MgI lines. The detailed abundance analysis and also the synthesis of the MgH…

Solar and Stellar Astrophysics · Physics 2020-12-23 B. P. Hema , Gajendra Pandey

The discovery of the Spite plateau in the abundances of 7Li for metal-poor stars led to the determination of an observationally deduced primordial lithium abundance. However, after the success of the Wilkinson Microwave Anisotropy Probe…

Astrophysics · Physics 2009-11-13 A. Hosford , S. G. Ryan , A. E. Garcia Perez , J. E. Norris , K. A. Olive

The lithium abundances in a few percent of giants exceed the value predicted by the standard stellar evolution models, and the mechanisms of Li enhancement are still under debate. The Large Sky Area Multi-Object Fiber Spectroscopic…

Solar and Stellar Astrophysics · Physics 2018-07-18 Y. T. Zhou , J. R. Shi , H. L. Yan , Q. Gao , J. B. Zhang , G. Zhao , K. Pan , Y. B. Kumar

The aim of the present study is to determine the Li abundances for a large set of the FGK dwarfs and to analyse the connections between the Li content, stellar parameters, and activity. Atmospheric parameters, rotational velocities and Li…

Solar and Stellar Astrophysics · Physics 2015-06-11 T. V. Mishenina , C. Soubiran , V. V. Kovtyukh , M. M. Katsova , M. A. Livshits

We present a survey of lithium abundances in 185 main- sequence field stars with Teff between 5600 and 6600 K and [Fe/H] from -1.4 to +0.2 based on high-resolution spectra of 130 stars and a reanalysis of data from Lambert et al. (1991).…

Astrophysics · Physics 2009-11-06 Y. Q. Chen , P. E. Nissen , T. Benoni , G. Zhao

Context: Lithium is a fragile element, which is easily destroyed in the stellar interior. The existence of lithium-rich giants still represents a challenge for stellar evolution models. Aims: We have collected a large database of…

Solar and Stellar Astrophysics · Physics 2015-05-27 L. Monaco , S. Villanova , C. Moni Bidin , G. Carraro , D. Geisler , P. Bonifacio , O. A. Gonzalez , M. Zoccali , L. Jilkova

We report the discovery of eight lithium-rich field giants found in a high resolution spectroscopic sample of over 700 metal-poor stars ([Fe/H]<-0.5) selected from the RAVE survey. The majority of the Li-rich giants in our sample are very…

A method for determining the effective temperature Teff of G- and K-type giants and supergiants is proposed. The method is based on the use of two photometric indices free from the interstellar absorption influence: the Q index in the UBV…

Solar and Stellar Astrophysics · Physics 2014-12-23 L. S. Lyubimkov , D. B. Poklad

We present data for four ultra-Li-deficient, warm, halo stars. The Li deficiency of two of these is a new discovery. Three of the four stars have effective temperatures Teff ~ 6300 K, in contrast to previously known Li-deficient halo stars…

Astrophysics · Physics 2009-10-31 Sean G. Ryan , Timothy C. Beers , Toshitaka Kajino , Katarina Rosolankova

With the existing and upcoming large multi-fibre low-resolution spectrographs, the question arises how precise stellar parameters such as Teff and [Fe/H] can be obtained from low-resolution K-band spectra with respect to traditional…

Solar and Stellar Astrophysics · Physics 2016-05-04 M. Schultheis , N. Ryde , G. Nandakumar

We report on spectroscopic analyses of three K giants previously suggested to be Li-rich: IRAS 12327-6523, IRAS 13539-4153, and IRAS 17596-3952. High-resolution optical spectra and the LTE model atmospheres are used to derive the stellar…

Astrophysics · Physics 2009-11-10 Bacham E. Reddy , David L. Lambert

In this paper, we report the discovery of two new super Li-rich K giants: HD~24960 and TYC~1751-1713-1. Based on high resolution ($R\approx 60,000$) spectroscopy, we have derived Li abundance of A(Li)$\approx$4.0~dex for both stars. Other…

Solar and Stellar Astrophysics · Physics 2018-11-07 Raghubar Singh , Bacham E. Reddy , Yerra Bharat Kumar

Helium-rich subdwarf B (He-sdB) stars represent a small group of low-mass hot stars with luminosities greater than those of conventional subdwarf B stars, and effective temperatures lower than those of subdwarf O stars. By measuring their…

Solar and Stellar Astrophysics · Physics 2015-05-20 Naslim N. , C. S. Jeffery , N. T. Behara , A. Hibbert

The lithium abundances for 378 G/K giants are derived with non-LTE correction considered. Among these, there are 23 stars that host planetary systems. The lithium abundance is investigated, as a function of metallicity, effective…

Solar and Stellar Astrophysics · Physics 2015-06-19 Y. J. Liu , K. F. Tan , L. Wang , G. Zhao , Bun'ei Sato , Y. Takeda , H. N. Li

Context: Recent attention has been directed to abundance variations among very young stars. Aims: To perform a detailed abundance study of the Herbig Ae star HD 101412, taking advantage of its unusually sharp spectral lines. Methods:…

Solar and Stellar Astrophysics · Physics 2016-08-14 C. R. Cowley , S. Hubrig , J. F. González , I. Savanov

Cool stars, such as M giants, can only be analysed in the near-infrared (NIR) regime due to the ubiquitous TiO features in optical spectra of stars with Teff < 4000 K. In dust obscured regions, like the inner bulge and Galactic Center, the…

Solar and Stellar Astrophysics · Physics 2023-07-05 G. Nandakumar , N. Ryde , L. Casagrande , G. Mace

We provide *lambda*6708 Li 1 measurements in 37 metal-poor stars, most of which are poorly-studied or have no previous measurements, from high-resolution and high-S/N spectroscopy obtained with the McDonald Observatory 2.1m and 2.7m…

Solar and Stellar Astrophysics · Physics 2015-06-03 Marc Schaeuble , Jeremy R. King

PDS365 is a newly detected rapidly rotating (vsin i = 20 km/s) single low mass giant star which with HD233517 and HD219025 forms a remarkable ensemble of single K giants with the unique properties of rapid rotation, very strong Li lines, an…

Astrophysics · Physics 2009-11-07 Natalia A. Drake , Ramiro de la Reza , Licio da Silva , David L. Lambert

One of the most important factors in determining the stellar lithium abundance is the effective temperature. In a previous study by the authors, new effective temperatures Teff for sixteen metal-poor halo dwarfs were derived using a local…

Solar and Stellar Astrophysics · Physics 2015-05-18 A. Hosford , A. E. Garcia Perez , R. Collet , S. G. Ryan , J. E. Norris , K. A. Olive
‹ Prev 1 2 3 10 Next ›