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Related papers: On Infrared Excesses Associated With Li-Rich K Gia…

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We searched for a correlation between the two anomalous properties of K giants: Li enhancement and IR excess from an unbiased survey of a large sample of RGB stars. A sample of 2000 low-mass K giants with accurate astrometry from the…

Solar and Stellar Astrophysics · Physics 2015-04-29 Y. Bharat Kumar , B. E. Reddy , C. Muthumariappan , G. Zhao

We have performed a search among low mass red giants for finding evidence for merger scenario for triggering He-flash and subsequent Li enhancement. We chose a sample of red giants from GALAH survey with well-measured Li abundances, and…

Solar and Stellar Astrophysics · Physics 2023-01-27 Anohita Mallick , Bacham E. Reddy , C. Muthumariappan

The origin of the Li-rich K giants is still highly debated. Here, we investigate the incidence of binarity among this family from a nine-year radial-velocity monitoring of a sample of 11 Li-rich K giants using the HERMES spectrograph…

Solar and Stellar Astrophysics · Physics 2020-07-13 A. Jorissen , H. Van Winckel , L. Siess , A. Escorza , D. Pourbaix , S. Van Eck

The discovery of Li-rich giant has cast a new challenge for the standard stellar evolution models, and to resolve this issue, the number of this type object has been rapidly increased because of the development of worldwide surveys these…

Solar and Stellar Astrophysics · Physics 2019-06-05 Yutao Zhou , Hongliang Yan , Jianrong Shi , S. Blanco-Cuaresma , Qi Gao , K. Pan , Xiaodong Xu , Junbo Zhang , Gang Zhao

Using photometric data from the 2MASS and GLIMPSE catalogues, I investigate the incidence of mid-infrared excesses (~10 microns) of G and K stars of luminosity class III. In order to obtain a large sample size, stars are selected using a…

Astrophysics · Physics 2009-06-23 Mark H. Jones

A model scenario has recently been introduced to explain the presence of very strong Li lines in the spectra of some low mass K giant stars (de la Reza et al. 1996). In this scenario all ordinary, Li poor, K giants become Li rich during a…

Astrophysics · Physics 2009-10-30 R. de la Reza , N. A. Drake , L. da Silva , C. A. O. Torres , E. L. Martin

With an aim to shed light on the origin of Li anomaly observed in a small fraction of red giants, we carried out a spectroscopic study on the observational characteristics of selected 20 bright Li-rich giants, in comparison with a large…

Solar and Stellar Astrophysics · Physics 2017-09-20 Yoichi Takeda , Akito Tajitsu

We present results of the analysis of a sample of 22 stars of spectral types from O7 to B5 and luminosity classes I-V for which Spitzer/IRS spectra are available. The IRS spectra of these stars are examined for signs of excess infrared (IR)…

Solar and Stellar Astrophysics · Physics 2018-11-28 R. Siebenmorgen , P. Scicluna , J. Krelowski

This paper reports follow-up photometric and spectroscopic observations, including warm Spitzer IRAC photometry of seven white dwarfs from the SDSS with apparent excess flux in UKIDSS K-band observations. Six of the science targets were…

Solar and Stellar Astrophysics · Physics 2012-06-06 J. Farihi , B. T. Gänsicke , P. R. Steele , J. Girven , M. R. Burleigh , E. Breedt , D. Koester

We have searched for Extremely Red Objects (EROs) around faint mid-IR selected galaxies in ELAIS fields. We find a significant overdensity, by factors of 2 to 5, of these EROs compared to field EROs in the same region and literature random…

Astrophysics · Physics 2009-11-10 P. Vaisanen , P. H. Johansson

The existence of K giant stars with high Li abundance continues to challenge the standard theory of stellar evolution. All recent extensive surveys in the Galaxy show the same result: about 1 % of the mainly normal slow rotating K giants…

Solar and Stellar Astrophysics · Physics 2012-09-25 Ramiro de la Reza , Natalia A. Drake

An analysis of low resolution spectra and infared data of 29 ISOGAL-DENIS sources with mid-IR excess is presented. Eight ISOGAL sources from our sample with 7-15 micron excess are found to be B and A-type stars, some of them with emission…

Astrophysics · Physics 2009-11-07 M. Schultheis , M. Parthasarathy , A. Omont , M. Cohen , S. Ganesh , F. Sevre , G. Simon

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

We explore the nature of Infrared Excess sources (IRX), which are proposed as candidates for luminous L_X(2-10keV)>1e43erg/s Compton Thick (N_H>2e24cm^{-2}$) QSOs at z~2. Lower redshift, z~1, analogues of the distant IRX population are…

High Energy Astrophysical Phenomena · Physics 2019-08-15 A. Georgakakis , M. Rowan-Robinson , K. Nandra , J. Digby-North , P. G. Perez-Gonzalez , G. Barro

We report on photometry and high-resolution spectroscopy for IRAS 19285+0517. The spectral energy distribution based on visible and near-IR photometry and far-IR fluxes shows that the star is surrounded by dust at a temperature of $T_{\rm…

Astrophysics · Physics 2009-11-07 Bacham E. Reddy , David L. Lambert , Bruce J. Hrivnak , Eric J. Bakker

Circumstellar debris disks are important because of their connection to planetary systems. An efficient way to identify these systems is through their infrared excess. Most studies so far concentrated on early-type or solar-type stars, but…

Solar and Stellar Astrophysics · Physics 2015-06-11 Henning Avenhaus , Hans Martin Schmid , Michael R. Meyer

A set of six debris disk candidates identified with IRAS or WISE excesses were observed at either 350 um or 450 um with the CSO. Five of the targets - HIP 51658, HIP 68160, HIP 73512, HIP 76375, and HIP 112460 - have among the largest…

Solar and Stellar Astrophysics · Physics 2015-06-16 J. Bulger , T. Hufford , A. Schneider , J. Patience , I. Song , R. J. De Rosa , A. Rajan , C. D. Dowell , D. McCarthy , C. Kulesa

In this Letter, we report on a low-resolution spectroscopic survey for Li-rich K giants among 2000 low mass (M <= 3 Msun) giants spanning the luminosity range from below to above the luminosity of the clump. Fifteen new Li-rich giants…

Solar and Stellar Astrophysics · Physics 2015-05-27 Yerra Bharat Kumar , Bacham E. Reddy , David L. Lambert

There are a number of faint compact infrared excess sources in the central stellar cluster of the Milky Way. Their nature and origin is unclear. In addition to several isolated objects of this kind we find a small but dense cluster of…

Instrumentation and Methods for Astrophysics · Physics 2015-06-11 A. Eckart , K. Muzic , S. Yazici , B. Shahzamanian , G. Witzel , N. Sabha , L. Moser , M. Garcia-Marin , M. Valencia-S. , B. Jalali , M. Bremer , C. Straubmeier , D. Kunneriath , J. Moultaka

We present 7 mm, 1.3 cm and 3.6 cm continuum observations made with the Very Large Array toward a sample of ten luminous IRAS sources that are believed to be regions of massive star formation. We detect compact 7 mm emission in four of…

Astrophysics · Physics 2016-08-30 Luis Zapata , Luis Rodriguez , Paul Ho , Henrik Beuther , Qizhou Zhang
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