Bibcode
Drake, A. J.; Graham, M. J.; Djorgovski, S. G.; Catelan, M.; Mahabal, A. A.; Torrealba, G.; García-Álvarez, D.; Donalek, C.; Prieto, J. L.; Williams, R.; Larson, S.; Christen sen, E.; Belokurov, V.; Koposov, S. E.; Beshore, E.; Boattini, A.; Gibbs, A.; Hill, R.; Kowalski, R.; Johnson, J.; Shelly, F.
Bibliographical reference
The Astrophysical Journal Supplement, Volume 213, Issue 1, article id. 9, 29 pp. (2014).
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7
2014
Citations
417
Refereed citations
380
Description
We present ~47,000 periodic variables found during the analysis of 5.4
million variable star candidates within a 20,000 deg2 region
covered by the Catalina Surveys Data Release-1 (CSDR1). Combining these
variables with type ab RR Lyrae from our previous work, we produce an
online catalog containing periods, amplitudes, and classifications for
~61,000 periodic variables. By cross-matching these variables with those
from prior surveys, we find that >90% of the ~8000 known periodic
variables in the survey region are recovered. For these sources, we find
excellent agreement between our catalog and prior values of luminosity,
period, and amplitude as well as classification. We investigate the rate
of confusion between objects classified as contact binaries and type c
RR Lyrae (RRc's) based on periods, colors, amplitudes, metallicities,
radial velocities, and surface gravities. We find that no more than a
few percent of the variables in these classes are misidentified. By
deriving distances for this clean sample of ~5500 RRc's, we trace the
path of the Sagittarius tidal streams within the Galactic halo.
Selecting 146 outer-halo RRc's with SDSS radial velocities, we confirm
the presence of a coherent halo structure that is inconsistent with
current N-body simulations of the Sagittarius tidal stream. We also find
numerous long-period variables that are very likely associated within
the Sagittarius tidal stream system. Based on the examination of 31,000
contact binary light curves we find evidence for two subgroups
exhibiting irregular light curves. One subgroup presents significant
variations in mean brightness that are likely due to chromospheric
activity. The other subgroup shows stable modulations over more than a
thousand days and thereby provides evidence that the O'Connell effect is
not due to stellar spots.
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Chemical Abundances in Stars
Stellar spectroscopy allows us to determine the properties and chemical compositions of stars. From this information for stars of different ages in the Milky Way, it is possible to reconstruct the chemical evolution of the Galaxy, as well as the origin of the elements heavier than boron, created mainly in stellar interiors. It is also possible to
Carlos
Allende Prieto