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Title: CHEMICAL SIGNATURES OF THE FIRST SUPERNOVAE IN THE SCULPTOR DWARF SPHEROIDAL GALAXY

Abstract

We present a homogeneous chemical abundance analysis of five of the most metal-poor stars in the Sculptor dwarf spheroidal galaxy. We analyze new and archival high resolution spectroscopy from Magellan/MIKE and VLT/UVES and determine stellar parameters and abundances in a consistent way for each star. Two of the stars in our sample, at [Fe/H] = −3.5 and [Fe/H] = −3.8, are new discoveries from our Ca K survey of Sculptor, while the other three were known in the literature. We confirm that Scl 07-50 is the lowest metallicity star identified in an external galaxy, at [Fe/H] = −4.1. The two most metal-poor stars both have very unusual abundance patterns, with striking deficiencies of the α elements, while the other three stars resemble typical extremely metal-poor Milky Way halo stars. We show that the star-to-star scatter for several elements in Sculptor is larger than that for halo stars in the same metallicity range. This scatter and the uncommon abundance patterns of the lowest metallicity stars indicate that the oldest surviving Sculptor stars were enriched by a small number of earlier supernovae, perhaps weighted toward high-mass progenitors from the first generation of stars the galaxy formed.

Authors:
; ;  [1]; ;  [2];  [3]
  1. Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)
  2. Kavli Institute for Astrophysics and Space Research and Department of Physics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States)
  3. ASML US, 77 Danbury Road., Wilton, CT 06897 (United States)
Publication Date:
OSTI Identifier:
22522009
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 802; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION SPECTROSCOPY; ELEMENT ABUNDANCE; EMISSION SPECTROSCOPY; HYDROGEN; IRON; MASS; METALLICITY; MILKY WAY; RESOLUTION; SUPERNOVAE

Citation Formats

Simon, Joshua D., Thompson, Ian B., Shectman, Stephen A., Jacobson, Heather R., Frebel, Anna, and Adams, Joshua J., E-mail: jsimon@obs.carnegiescience.edu, E-mail: ian@obs.carnegiescience.edu, E-mail: shec@obs.carnegiescience.edu, E-mail: hjr@mit.edu, E-mail: afrebel@mit.edu, E-mail: jja439@gmail.com. CHEMICAL SIGNATURES OF THE FIRST SUPERNOVAE IN THE SCULPTOR DWARF SPHEROIDAL GALAXY. United States: N. p., 2015. Web. doi:10.1088/0004-637X/802/2/93.
Simon, Joshua D., Thompson, Ian B., Shectman, Stephen A., Jacobson, Heather R., Frebel, Anna, & Adams, Joshua J., E-mail: jsimon@obs.carnegiescience.edu, E-mail: ian@obs.carnegiescience.edu, E-mail: shec@obs.carnegiescience.edu, E-mail: hjr@mit.edu, E-mail: afrebel@mit.edu, E-mail: jja439@gmail.com. CHEMICAL SIGNATURES OF THE FIRST SUPERNOVAE IN THE SCULPTOR DWARF SPHEROIDAL GALAXY. United States. doi:10.1088/0004-637X/802/2/93.
Simon, Joshua D., Thompson, Ian B., Shectman, Stephen A., Jacobson, Heather R., Frebel, Anna, and Adams, Joshua J., E-mail: jsimon@obs.carnegiescience.edu, E-mail: ian@obs.carnegiescience.edu, E-mail: shec@obs.carnegiescience.edu, E-mail: hjr@mit.edu, E-mail: afrebel@mit.edu, E-mail: jja439@gmail.com. Wed . "CHEMICAL SIGNATURES OF THE FIRST SUPERNOVAE IN THE SCULPTOR DWARF SPHEROIDAL GALAXY". United States. doi:10.1088/0004-637X/802/2/93.
@article{osti_22522009,
title = {CHEMICAL SIGNATURES OF THE FIRST SUPERNOVAE IN THE SCULPTOR DWARF SPHEROIDAL GALAXY},
author = {Simon, Joshua D. and Thompson, Ian B. and Shectman, Stephen A. and Jacobson, Heather R. and Frebel, Anna and Adams, Joshua J., E-mail: jsimon@obs.carnegiescience.edu, E-mail: ian@obs.carnegiescience.edu, E-mail: shec@obs.carnegiescience.edu, E-mail: hjr@mit.edu, E-mail: afrebel@mit.edu, E-mail: jja439@gmail.com},
abstractNote = {We present a homogeneous chemical abundance analysis of five of the most metal-poor stars in the Sculptor dwarf spheroidal galaxy. We analyze new and archival high resolution spectroscopy from Magellan/MIKE and VLT/UVES and determine stellar parameters and abundances in a consistent way for each star. Two of the stars in our sample, at [Fe/H] = −3.5 and [Fe/H] = −3.8, are new discoveries from our Ca K survey of Sculptor, while the other three were known in the literature. We confirm that Scl 07-50 is the lowest metallicity star identified in an external galaxy, at [Fe/H] = −4.1. The two most metal-poor stars both have very unusual abundance patterns, with striking deficiencies of the α elements, while the other three stars resemble typical extremely metal-poor Milky Way halo stars. We show that the star-to-star scatter for several elements in Sculptor is larger than that for halo stars in the same metallicity range. This scatter and the uncommon abundance patterns of the lowest metallicity stars indicate that the oldest surviving Sculptor stars were enriched by a small number of earlier supernovae, perhaps weighted toward high-mass progenitors from the first generation of stars the galaxy formed.},
doi = {10.1088/0004-637X/802/2/93},
journal = {Astrophysical Journal},
number = 2,
volume = 802,
place = {United States},
year = {Wed Apr 01 00:00:00 EDT 2015},
month = {Wed Apr 01 00:00:00 EDT 2015}
}