321 citations · 2.2k across the 67 of their papers we have counts for
24 papers · 1 filter
Highly He-Rich Matter Dredged Up by Extra Mixing through Stellar Encounters in Globular Clusters
Takuma Suda, Takuji Tsujimoto, Toshikazu Shigeyama +1
The unveiled main-sequence splitting in omega Centauri as well as NGC 2808 suggests that matter highly-enriched in He (in terms of its mass fraction Y~0.4) was produced and made th…
Surface pollution of main-sequence stars through encounters with AGB ejecta in omega Centauri
Takuji Tsujimoto, Toshikazu Shigeyama, Takuma Suda
The origin of a double main-sequence (MS) in omega Centauri is explored. We have shown from theoretical calculations on the stellar evolution that the colors of MS stars are shifte…
First Detection of NaI D lines in High-Redshift Damped Lyman-alpha Systems
Sohei Kondo, Naoto Kobayashi, Yosuke Minowa +15
A Near-infrared (1.18-1.35 micron) high-resolution spectrum of the gravitationally-lensed QSO APM 08279+5255 was obtained with the IRCS mounted on the Subaru Telescope using the AO…
Implications of Elemental Abundances in Dwarf Spheroidal Galaxies
Takuji Tsujimoto
Unusual elemental abundance patterns observed for stars belonging to nearby dwarf spheroidal (dSph) galaxies are discussed. Analysis of the [alpha/H] vs. [Fe/H] diagrams where alph…
Accretion of dust grains as a possible origin of metal-poor stars with low alpha/Fe ratios
Toshikazu Shigeyama, Takuji Tsujimoto
The origin of low alpha/Fe ratios in some metal-poor stars, so called low-alpha stars, is discussed. It is found that most of low-alpha stars in the Galaxy are on the main-sequence…
Excavation of the first stars
Toshikazu Shigeyama, Takuji Tsujimoto, Yuzuru Yoshii
The external pollution of the first stars in the Galaxy is investigated. The first stars were born in clouds composed of the pristine gas without heavy elements. These stars accret…