Nitrogen Abundances and the Distance Moduli of the Pleiades and Hyades
| Autor: | Yu Chen, Blake Miller, Ann Merchant Boesgaard, Jeremy R. King |
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| Rok vydání: | 2013 |
| Předmět: |
Physics
chemistry.chemical_element FOS: Physical sciences Astronomy and Astrophysics Astrophysics Nitrogen Moduli Stars Distance modulus Astrophysics - Solar and Stellar Astrophysics chemistry Space and Planetary Science Disc Parallax Spectroscopy Pleiades Solar and Stellar Astrophysics (astro-ph.SR) |
| DOI: | 10.48550/arxiv.1309.1540 |
| Popis: | Recent reanalyses of HIPPARCOS parallax data confirm a previously noted discrepancy with the Pleiades distance modulus estimated from main-sequence fitting in the color-magnitude diagram. One proposed explanation of this distance modulus discrepancy is a Pleiades He abundance that is significantly larger than the Hyades value. We suggest that, based on our theoretical and observational understanding of Galactic chemical evolution, nitrogen abundances may serve as a proxy for helium abundances of disk stars. Utilizing high-resolution near-UV Keck/HIRES spectroscopy, we determine N abundances in the Pleiades and Hyades dwarfs from NH features in the 3330 Ang region. While our Hyades N abundances show a modest 0.2 dex trend over a 800 K Teff range, we find the Pleiades N abundance (by number) is 0.13+/-0.05 dex lower than in the Hyades for stars in a smaller overlapping Teff range around 6000 K; possible systematic errors in the lower Pleiades N abundance result are estimated to be at the Accepted for publication in the Publications of the Astronomical Society of the Pacific |
| Databáze: | OpenAIRE |
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