中文
相关论文

相关论文: A very reduced upper limit on the interstellar abu…

200 篇论文

We present observations of the Be II 313.0 nm resonance doublet in 14 halo and old disk stars with metallicities ranging from [Fe/H]=-0.4 to about -3.0 obtained with the CASPEC spectrograph of the ESO 3.6m telescope at a FWHM about 8.6 km/s…

天体物理学 · 物理学 2007-05-23 P. Molaro , P. Bonifacio , F. Castelli , L. Pasquini

The study of Be in stars of differing metal content can elucidate the formation mechanisms and the Galactic chemical evolution of Be. We have obtained high-resolution, high signal-to-noise spectra of the resonance lines of Be II in eight…

天体物理学 · 物理学 2009-11-13 Ann Merchant Boesgaard , Megan C. Novicki

We report new observations of molecular oxygen in absorption at z=0.685 in front of the radio source B0218+357. The lines at 56.3 and 118.7 GHz have been observed, redshifted to 33.4 and 70.5 GHz respectively, with the 12m at Kitt Peak, 43m…

天体物理学 · 物理学 2007-05-23 F. Combes , T. Wiklind , N. Nakai , Paris Observatory , Onsala Observatory , Nobeyama Observatory

The present-day abundance of beryllium in the solar atmosphere provides clues about mixing mechanisms within stellar interiors. However, abundance determinations based on the Be II 313.107 nm line are prone to systematic errors due to…

太阳与恒星天体物理 · 物理学 2024-09-09 A. M. Amarsi , D. Ogneva , G. Buldgen , N. Grevesse , Y. Zhou , P. S. Barklem

An extensive beryllium abundance analysis was conducted for 118 solar analogs (along with 87 FGK standard stars) by applying the spectrum synthesis technique to the near-UV region comprising the Be II line at 3131.066 A, in an attempt to…

太阳与恒星天体物理 · 物理学 2015-05-27 Yoichi Takeda , Akito Tajitsu , Satoshi Honda , Satoshi Kawanomoto , Hiroyasu Ando , Takashi Sakurai

We have determined beryllium abundances for 25 metal-poor stars based on the high resolution and high signal-to-noise ratio spectra from the VLT/UVES database. Our results confirm that Be abundances increase with Fe, supporting the global…

天体物理学 · 物理学 2009-11-13 K. F. Tan , J. R. Shi , G. Zhao

Beryllium is not destroyed as easily as Li, so the abundances of Li and Be together can tell us more about the internal physical processes in stars than either element can alone. We have obtained high-resolution (45,000) and high…

天体物理学 · 物理学 2009-11-07 Ann Merchant Boesgaard , Jeremy R. King

An extensive spectroscopic study was carried out for the beryllium abundances of 200 red giants (mostly of late G and early K type), which were determined from the near-UV Be II 3131.066 line based on high-dispersion spectra obtained by…

太阳与恒星天体物理 · 物理学 2015-06-22 Yoichi Takeda , Akito Tajitsu

We have determined Be abundances in 50 F and G dwarfs in the mass range of 0.9 $\leq$ M$_\odot$ $\leq$ 1.1 as determined by Lambert & Reddy. The effective temperatures are 5600 to 6400 K and metallicities from $-$0.65 to +0.11. The spectra…

天体物理学 · 物理学 2015-05-13 Ann Merchant Boesgaard , Julie A. Krugler

We have detected a broad interstellar absorption band centred close to 7700 \r{A} and with a FWHM of 176.6$\pm$3.9 \r{A}. This is the first such absorption band detected in the optical range and is significantly wider than the numerous…

星系天体物理 · 物理学 2021-01-13 J. Maíz Apellániz , R. H. Barbá , J. A. Caballero , R. C. Bohlin , C. Fariña

We report on a new spectroscopic analysis of the very metal deficient star G 64-12 ([Fe/H]=-3.3), aimed at determining, for the first time, its Be content. The spectra were observed during the Science Verification of UVES, the ESO VLT…

天体物理学 · 物理学 2007-05-23 F. Primas , M. Asplund , P. E. Nissen , V. Hill

We use new Space Telescope Imaging Spectrograph (STIS) and archival Goddard High Resolution Spectrograph (GHRS) observations to study interstellar B II 1362 and O I 1355 absorption along seven sightlines. Our new column density…

天体物理学 · 物理学 2009-10-31 J. Christopher Howk , Kenneth R. Sembach , Blair D. Savage

We report on new FUSE far-UV spectroscopy of the most metal-poor blue compact dwarf galaxy I Zw 18. The new data represent an improvement over previous FUSE spectra by a factor of 1.7 in the signal-to-noise. Together with a larger spectral…

天体物理学 · 物理学 2009-11-07 A. Aloisi , S. Savaglio , T. M. Heckman , C. G. Hoopes , C. Leitherer , K. R. Sembach

The light elements, Li, Be, and B, provide tracers for many aspects of astronomy including stellar structure, Galactic evolution, and cosmology. We have taken spectra of Be in 117 metal-poor stars ranging in metallicity from [Fe/H] = -0.5…

太阳与恒星天体物理 · 物理学 2015-05-30 Ann Merchant Boesgaard , Jeffrey A. Rich , Emily M. Levesque , Brendan P. Bowler

We present new observations of the binary Sirius A / Sirius B performed with HST-GHRS. Two interstellar clouds are detected on this sightline, one of them being identified as the Local Interstellar Cloud (LIC). The interstellar structure of…

天体物理学 · 物理学 2007-05-23 G. Hebrard , C. Mallouris , R. Ferlet , D. Koester , M. Lemoine , A. Vidal-Madjar , D. York

Beryllium is a light element with one single stable isotope, 9Be, which is a pure product of cosmic-ray spallation in the interstellar medium. Beryllium abundances in late-type stars can be used in studies about evolutionary mixing,…

太阳与恒星天体物理 · 物理学 2022-03-31 Rodolfo Smiljanic , Andre Rodrigo da Silva , Riano E. Giribaldi

There are nine metal-deficient stars that have Li abundances well below the Li plateau that is defined by over 100 unevolved stars with temperatures above 5800 K and values of [Fe/H] $<$ $-$1.0. Abundances of Be have been determined for…

天体物理学 · 物理学 2009-11-13 Ann Merchant Boesgaard

The abundance of beryllium in the oldest, most metal-poor stars acts as a probe of early star formation and Galactic chemical evolution. We have analyzed high-resolution, high signal-to-noise Keck/HIRES spectra of 24 stars with [Fe/H] from…

星系天体物理 · 物理学 2011-02-11 Jeffrey A. Rich , Ann Merchant Boesgaard

Aims: To measure the beryllium abundance in two TO stars of the Globular Cluster NGC 6752, one oxygen rich and sodium poor, the other presumably oxygen poor and sodium rich. Be abundances in these stars are used to put on firmer grounds the…

天体物理学 · 物理学 2015-06-24 Luca Pasquini , Piercarlo Bonifacio , Sofia Randich , Daniele Galli , Raffaele G. Gratton , B. Wolff

Abundances of beryllium in metal-poor stars scale linearly with metallicity down to [Fe/H] ~ -3.0. In the stars where Be has been detected at this extremely metal-poor regime, an increased abundance scatter has been previously reported.…

太阳与恒星天体物理 · 物理学 2021-02-10 Rodolfo Smiljanic , Mateusz G. Zych , Luca Pasquini
‹ 上一页 1 2 3 10 下一页 ›