49,124 research outputs found
Radial Velocities and Pulsation Ephemerides of 11 Field RR Lyrae Stars
We present new radial velocities, improved pulsation periods and reference
epoch s of 11 field RR Lyrae ab-type variables: AS Vir, BS Aps, CD Vel, DT Hya,
RV Oct, TY Gru, UV Oct, V1645 Sgr, WY Ant, XZ Aps and Z Mic. This study is
based on high resolution spectra obtained with the echelle spectro graph of the
2.5-m du Pont telescope at Las Campanas Observatory. We obtained ~200 spectra
per star (i.e, total of ~2300 spectra) distributed more or less uniformly
throughout their pulsation cycles. Radial velocity curves and photometric
lightcurves phased to our new ephemerides are presented for all program stars.
In a subsequent paper, we will use these spectra to derive stellar atmospheric
parameters and chemical compositions throughout the pulsational cycles, based
purely on spectroscopic constraints.Comment: 28 pages, 14 figures, 5 tables. Accepted for publication in ApJ
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Initial Coin Offerings: Innovation, Democratization and the SEC
Initial coin offerings are a source of controversy in the world of startup fundraising, and their legality is, at best, an open question. Amid soaring valuations and rumors of looming SEC action, investors and issuers alike are scrambling to forge a path forward for the token-based startups of tomorrow. While issuers may soon be forced to comply with United States securities laws, the existing regime is inadequate because it does not allow startups to capture the unique benefits of coin sales and, more importantly, it does not allow eager American investors to take part in funding the world’s next generation of technology companies
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