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We present Spitzer/IRAC 4.5-micron transit photometry of GJ3470b, a Neptune-size planet orbiting a M1.5 dwarf star with a 3.3-day period recently discovered in the course of the HARPS M-dwarf survey. We refine the stellar parameters by…

We present stellar parameters and abundances of 13 elements for 18 very metal-poor (VMP; [Fe/H] $<$ -2.0) stars, selected as extremely metal-poor (EMP; [Fe/H] $<$ -3.0) candidates from SDSS and LAMOST survey. High-resolution spectroscopic…

Ancient, very metal-poor stars offer a window into the earliest epochs of galaxy formation and assembly. We combine data from the H3 Spectroscopic Survey and Gaia to measure metallicities, abundances of $\alpha$ elements, stellar ages, and…

(Abbreviated) We present a detailed analysis of the space motions of 1203 solar-neighborhood stars with metal abundances [Fe/H] <= -0.6, on the basis of a recently revised and supplemented catalog of metal-poor stars selected without…

Astrophysics · Physics 2009-05-29 M. Chiba , T. C. Beers

We report on the observations of two ultra metal-poor (UMP) stars with [Fe/H]~-4.0 including one new discovery. The two stars are studied in the on-going and quite efficient project to search for extremely metal-poor (EMP) stars with LAMOST…

Solar and Stellar Astrophysics · Physics 2015-08-06 Haining Li , Wako Aoki , Gang Zhao , Satoshi Honda , Norbert Christlieb , Takuma Suda

The halos of disk galaxies form a crucial connection between the galaxy disk and the intergalactic medium. Massive stars, HII regions, or dwarf galaxies located in the halos of galaxies are potential tracers of recent accretion and/or…

Astrophysics of Galaxies · Physics 2018-11-28 Y. Stein , D. J. Bomans , P. Kamphuis , E. Jütte , M. Langener , R. -J. Dettmar

Helium-burning hot subdwarf stars of spectral types O and B (sdO/B) are thought to be produced through various types of binary interaction. The helium-rich hot subdwarf star EC22536-5304 was recently found to be extremely enriched in lead.…

Solar and Stellar Astrophysics · Physics 2021-09-22 M. Dorsch , C. S. Jeffery , A. Irrgang , V. Woolf , U. Heber

X-ray and near-IR surveys of the central 2x0.8 degrees of the Galactic Centre have revealed a population of X-ray bright massive stars. However, the nature of the emission, originating in a wind collision zone or via accretion onto a…

Solar and Stellar Astrophysics · Physics 2015-05-14 J. S. Clark , P. A. Crowther , V. J. Mikles

Fast jets are thought to be a crucial ingredient of star formation because they might extract angular momentum from the disk and thus allow mass accretion onto the star. However, it is unclear whether jets are ubiquitous, and likewise,…

We present chemical abundances of the very bright metal-poor star HD~1936 based on high-resolution and high SNR spectra from AUKR. We obtain the abundances of 29 atomic species with atomic numbers between 3 and 63. In this context, the…

Solar and Stellar Astrophysics · Physics 2024-02-16 Şeyma Çalışkan , Jannat Mushreq Kamil Alazzawi , Yahya Nasolo

The enigma source, RX J1856.5-3754, is one of the so-called dim thermal neutron stars. Two puzzles of RXJ1856.5-3754 exist: (1) the observational X-ray spectrum is completely featureless; (2) the UV-optical intensity is about seven times…

Astrophysics · Physics 2007-05-23 Y. L. Yue , X. H. Cui , R. X. Xu

In this poster we present a detailed chemical analysis of the RV Tauri star of low intrinsic metallicity, V453 Oph ([Fe/H]=-2.2), which shows a mild but clear s-process surface overabundance. This result is strengthened by a relative…

Astrophysics · Physics 2009-11-10 Pieter Deroo , Stephane Goriely , Lionel Siess , Maarten Reyniers , Hans Van Winckel

Recent studies of chemical abundances in metal-poor Halo stars show the existence of different populations, which is important for studies of Galaxy formation and evolution. Here we revisit the twin pair of chemically anomalous stars HD…

Solar and Stellar Astrophysics · Physics 2018-02-22 Henrique Reggiani , Jorge Meléndez

Direct observations of low-mass, low-metallicity galaxies at $z\gtrsim4$ provide an indispensable opportunity for detailed inspection of the ionization radiation, gas flow, and metal enrichment in sources similar to those that reionized the…

The most metal-poor stars in the Milky Way witnessed the early phases of formation of the Galaxy, and have chemical compositions that are close to the pristine mixture from Big Bang nucleosynthesis, polluted by one or few supernovae. Only…

We present rest-frame optical images and spectra of the gravitationally lensed, star-forming galaxy J0900+2234 (z=2.03). The observations were performed with the newly commissioned LUCIFER1 near-infrared instrument mounted on the Large…

With the progressive release of data from numerous sky surveys, humanity has entered the era of astronomical big data. Multi-wavelength, multi-method research is playing an increasingly crucial role. Binaries account for a substantial…

Solar and Stellar Astrophysics · Physics 2025-10-14 Yanhui Chen , Chaomi Duan , Baokun Sun

We have discovered a new X-ray emitting compact binary that is the likely counterpart to the unassociated Fermi-LAT GeV $\gamma$-ray source 4FGL J1120.0-2204, the second brightest Fermi source that still remains formally unidentified. Using…

High Energy Astrophysical Phenomena · Physics 2022-03-02 Samuel J. Swihart , Jay Strader , Elias Aydi , Laura Chomiuk , Kristen C. Dage , Adam Kawash , Kirill V. Sokolovsky , Elizabeth C. Ferrara

We report the chemical abundance pattern of GS\_3073, a galaxy at $z=5.55$ which was previously confirmed to host an overmassive active black hole, by leveraging the detection of about 40 emission lines, combining JWST/NIRSpec observations…

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