Related papers: The very lithium rich post-AGB SB2 binary HD172481

Lithium rich giant stars are rare objects. For some of them, Li enrichment exceeds abundance of this element found in solar system meteorites, suggesting that these stars have gone through a Li enhancement process. We identified a Li rich…

The connection between helium-rich hot subdwarfs of spectral types O and B (He-sdB) has been relatively unexplored since the latter were found in significant numbers in the 1980's. In order to explore this connection further, we have…

HD 176465 is a binary system whose both components are solar-like pulsators and whose oscillation frequencies were observed by the \kepler\ mission. In this paper we have modeled the asteroseismic and spectroscopic data of the stars, and…

Observations at various wavelengths of late B-type stars exhibiting strong overabundances of the chemical elements Hg and Mn in their atmospheres indicate that these stars are frequently found in binary and multiple systems. We intend to…

We report new observations of SL2SJ021737-051329, a lens system consisting of a bright arc at z=1.84435, magnified ~17x by a massive galaxy at z=0.65. SL2SJ0217 is a low-mass (M <10^9 M*), low-metallicity (Z~1/20 Z*) galaxy, with extreme…

Second order optical nonlinear processes involve the coherent mixing of two electromagnetic waves to generate a new optical frequency, which plays a central role in a variety of applications, such as ultrafast laser systems, rectifiers,…

Abridged: We report the discovery of two, new, rare, wide, double-degenerate binaries that each contain a magnetic and a non-magnetic star. The components of SDSSJ092646.88+132134.5 + J092647.00+132138.4 and SDSSJ150746.48+521002.1 +…

New spectroscopic observations of the LBV/WR multiple system HD5980 in the Small Magellanic Cloud are used to address the question of the masses and evolutionary status of the two very luminous stars in the 19.3d eclipsing binary system.…

Weak G-band (WGB) stars are a rare class of cool luminous stars that present a strong depletion in carbon, but also lithium abundance anomalies that have been little explored in the literature since the first discovery of these peculiar…

The emission-line binary ALS 8814 was recently proposed as a Be star + black hole (BH) binary based on large-amplitude radial velocity (RV) variations of a Be star and non-detection of spectroscopic features from a luminous companion. We…

Similar to some other two-Higgs doublet models (2HDM), the flipped 2HDM admits of a light pseudoscalar physical state whose mass can be well below 50 GeV. The fact that the pseudoscalar decays dominantly into a $b{\bar b}$ pair makes its…

We present a high S/N spectrum for the quasar PG 1138+222. We detect a very broad HeII$\lambda$4686 emission line component with twice the FWHM of the conventional broad line region (BLR) as evidenced by the Balmer lines. The profile shape…

We report the detection of the Pb I 4057.8A line in the very metal-poor ([Fe/H]=-2.7), carbon-rich star, LP625-44. We determine the abundance of Pb ([Pb/Fe] = 2.65) and 15 other neutron-capture elements. The abundance pattern between Ba and…

Observations show that the 12.4 d binary system descending from the recent supernova SN 2022jli closely fits hypotheses of how low-mass X-ray binaries form, but requires an apparently super-Eddington accretion luminosity from the accreting…

We present an analysis of nine bright spectroscopic binaries (HD 1585, HD 6613, HD 12390, HD 39923, HD 55201, HD 147430, HD 195543, HD 202699, HD 221643), which have orbital periods of P > 500 days. These well-separated binaries are the…

We present the discovery of 2MASS J21321145+1341584AB as a closely separated (0.066") very low-mass field dwarf binary resolved in the near-infrared by the Keck II Telescope using laser guide star adaptive optics. Physical association is…

We present a study of the lithium abundances of a sample of evolved components of Chromospherically Active Binary Systems. We show that a significant part of them have lithium excesses, independently of their mass and evolutionary stage.…

We report on our search for spectroscopic binaries among a sample of AGB stars. Observations were carried out in the framework of the monitoring of radial velocities of (candidate) binary stars performed at the Mercator 1.2m telescope,…

We report on the discovery of a super-Li rich turn-off star in the old (12 Gyr), metal poor ([Fe/H]=-2.1 dex) globular cluster (GC) NGC 6397, based on high-resolution MIKE/Magellan spectra. This star shows an unusually high lithium…

A near-infrared excess is detected at the white dwarf PHL5038 in UKIDSS photometry, consistent with the presence of a cool, substellar companion. We have obtained H- and K-grism spectra and images of PHL5038 using NIRI on Gemini North. The…