1. Timothy C. Beers University of Notre Dame
Fingerprints of the First Stars: CEMP-no Stars in the Halo of the Milky Way
Timothy C. Beers
University of Notre Dame
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SDSS

2. Expected Signatures in the Early Universe
First-generation (high-mass) stars of primordial H/He formed, quickly evolved, and exploded
Distributed (pre or post explosion) their nucleosynthetic products
Next-generation stars formed from this polluted gas
Efficient cooling  low-mass stars with long lifetimes (13+ Billion Yrs)
A characteristic abundance pattern identified in halo of MW
High carbon, low other metals: the CEMP-no stars
Numerous CEMP-no stars now identified, likely originating in Ultra Faint Galaxies

3. CEMP-no Stars are Associated with UNIQUE Light-Element Abundance Patterns
HE [Fe/H] = -5.3, [C/Fe] = (Christlieb et al. 2002)
HE [Fe/H] = -5.5, [C/Fe] = (Frebel et al. 2005)
 CH G-band HE

4. Something You Don’t Often See
An Object of COSMOLOGICAL significance
with diffraction spikes !
Metallicity 1/10,000th solar ([Fe/H] = -3.8),
CEMP-no star
Bright – 9th magnitude – visible with binoculars,
600 light years from Earth
Observed with 8m Subaru telescope and
Hubble Space Telescope
BD+44: 493

5. Born Where ? In the First Galaxies – The Ultra Faint Dwarfs
Based on available spectroscopy
-- Numbers of CEMP-no stars
SEGUE-1: 3 of 7
Uma II: 2 of 3
Ret II: 3 of 9
Tuc II: 3 of 7
Boo I: ~20% (some CEMP-s)
CEMP-no
Dark Energy Survey
Frebel et al. (2016)

6. ALL (CEMP-no / CEMP-s) for the AEGIS Sample
Yoon et al. (submitted)
~2 times higher
Previous frequencies (SDSS)

7. The Story So Far …
The CEMP-no stars document the nucleosynthesis products of first generations of star formation in the early Universe
Evidence strongly suggests CEMP-no stars were born in low-mass Ultra Faint Dwarf galaxies, then accreted by the Milky Way’s halo
Some CEMP-no stars are quite bright – Enables high-resolution abundance analyses with ground and space-based telescopes
Understanding the chemistry of the First Stars can be done “locally” in the Milky Way – not just by study of faint objects more then billion light years away
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