title: Massive stars. A chemical signature of first-generation very massive stars.
abstract: Numerical simulations of structure formation in the early universe predict the formation of some fraction of stars with several hundred solar masses. No clear evidence of supernovae from such very massive stars has, however, yet been found in the chemical compositions of Milky Way stars. We report on an analysis of a very metal-poor star SDSS J001820.5-093939.2, which possesses elemental-abundance ratios that differ significantly from any previously known star. This star exhibits low [α-element Fe] ratios and large contrasts between the abundances of odd and even element pairs, such as scandium/titanium and cobalt/nickel. Such features have been predicted by nucleosynthesis models for supernovae of stars more than 140 times as massive as the Sun, suggesting that the mass distribution of first-generation stars might extend to 100 solar masses or larger.
authors.affiliation: National Astronomical Observatory of Japan (NAOJ), 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan. Department of Astronomical Science, School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI), 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan. aoki.wako@nao.ac.jp.
authors.forename: W
authors.initials: W
authors.lastname: Aoki
authors.affiliation: Department of Physics, Faculty of Science and Engineering, Konan University, 8-9-1 Okamoto, Kobe, Hyogo 658-8501, Japan. Kavli Institute for the Physics and Mathematics of the Universe (WPI), the University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8569, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Tominaga
authors.affiliation: Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46656, USA. JINA, Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, IN 46556, USA.
authors.forename: T C
authors.initials: TC
authors.lastname: Beers
authors.affiliation: Center for Astronomy, University of Hyogo, 407-2, Nishigaichi, Sayo-cho, Sayo, Hyogo 679-5313, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Honda
authors.affiliation: Department of Astronomy, New Mexico State University, Las Cruces, NM 88003, USA.
authors.forename: Y S
authors.initials: YS
authors.lastname: Lee