THE 300 km s{sup -1} STELLAR STREAM NEAR SEGUE 1: INSIGHTS FROM HIGH-RESOLUTION SPECTROSCOPY OF ITS BRIGHTEST STAR

Journal Article · Mon Jul 01 00:00:00 EDT 2013 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/771/1/39· OSTI ID:22140203

Frebel, Anna; Casey, Andrew R. ^[1]; Lunnan, Ragnhild ^[2]; Norris, John E. ^[3]; Wyse, Rosemary F. G. ^[4]; Gilmore, Gerard ^[5]

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1. Massachusetts Institute of Technology, Kavli Institute for Astrophysics and Space Research, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States)
2. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
3. Research School of Astronomy and Astrophysics, Australian National University, Mount Stromlo Observatory, Cotter Road, Weston, ACT 2611 (Australia)
4. Department of Physics and Astronomy, Johns Hopkins University, 300 N. Charles Street, Baltimore, MD 21218 (United States)
5. Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom)

We present a chemical abundance analysis of 300S-1, the brightest likely member star of the 300 km s{sup -1} stream near the faint satellite galaxy Segue 1. From a high-resolution Magellan/MIKE spectrum, we determine a metallicity of [Fe/H] = -1.46 {+-} 0.05 {+-} 0.23 (random and systematic uncertainties) for star 300S-1, and find an abundance pattern similar to typical halo stars at this metallicity. Comparing our stellar parameters to theoretical isochrones, we estimate a distance of 18 {+-} 7 kpc. Both the metallicity and distance estimates are in good agreement with what can be inferred from comparing the Sloan Digital Sky Survey photometric data of the stream stars to globular cluster sequences. While several other structures overlap with the stream in this part of the sky, the combination of kinematic, chemical, and distance information makes it unlikely that these stars are associated with either the Segue 1 galaxy, the Sagittarius Stream, or the Orphan Stream. Streams with halo-like abundance signatures, such as the 300 km s{sup -1} stream, present another observational piece for understanding the accretion history of the Galactic halo.

• OSTI ID: 22140203
• Journal Information: Astrophysical Journal, Vol. 771, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ABUNDANCE
DISTANCE
GALAXIES
GALAXY NUCLEI
MAGELLANIC CLOUDS
RANDOMNESS
RESOLUTION
SATELLITES
SKY
SPECTRA
SPECTROSCOPY
STARS
STREAMS