TY - JOUR
T1 - Galactic Doppelgangers
T2 - The Chemical Similarity among Field Stars and among Stars with a Common Birth Origin
AU - Ness, M.
AU - Rix, H. W.
AU - Hogg, David W.
AU - Casey, A. R.
AU - Holtzman, J.
AU - Fouesneau, M.
AU - Zasowski, G.
AU - Geisler, D.
AU - Shetrone, M.
AU - Minniti, D.
AU - Frinchaboy, Peter M.
AU - Roman-Lopes, Alexandre
N1 - Funding Information:
D.W.H. was partially supported by the NSF (grants IIS-1124794 and AST-1517237), NASA (grant NNX12AI50G), and the Moore-Sloan Data Science Environment at NYU.
Funding Information:
M.N. and H.-W.R. acknowledge funding from the European Research Council under the European Union’s Seventh Framework Programme (FP 7) ERC Advanced Grant Agreement n. [321035]. H.-W.R. acknowledges support of the Miller Institute at UC Berkeley through a visiting professorship during the completion of this work.
Funding Information:
P.M.F gratefully acknowledges support from the National Science Foundation through award AST1311835.
Funding Information:
D.G. and D.M. gratefully acknowledge support from the BASAL Centro de Astrofsica y Tecnologias Afines (CATA) grant PFB-06/2007. D.M. is also supported by the Ministry for the Economy, Development, and Tourism, Programa Iniciativa Cientifica Milenio grant IC120009, awarded to the Millennium Institute of Astrophysics (MAS), and by FONDECYT No. 1130196.
Funding Information:
Funding for the Sloan Digital Sky Survey IV has been provided by the Alfred P. Sloan Foundation, the U.S. Department of Energy Office of Science, and the Participating Institutions. SDSS acknowledges support and resources from the Center for High-Performance Computing at the University of Utah. The SDSS Web site ishttp://www.sdss.org.
PY - 2018/2/1
Y1 - 2018/2/1
N2 - We explore to what extent stars within Galactic disk open clusters resemble each other in the high-dimensional space of their photospheric element abundances and contrast this with pairs of field stars. Our analysis is based on abundances for 20 elements, homogeneously derived from APOGEE spectra (with carefully quantified uncertainties of typically 0.03 dex). We consider 90 red giant stars in seven open clusters and find that most stars within a cluster have abundances in most elements that are indistinguishable (in a X2-sense) from those of the other members, as expected for stellar birth siblings. An analogous analysis among pairs of >1000 field stars shows that highly significant abundance differences in the 20 dimensional space can be established for the vast majority of these pairs, and that the APOGEE-based abundance measurements have high discriminating power. However, pairs of field stars whose abundances are indistinguishable even at 0.03 dex precision exist: ∼0.3% of all field star pairs and ∼1.0% of field star pairs at the same (solar) metallicity [Fe/H]=0±0.02. Most of these pairs are presumably not birth siblings from the same cluster, but rather doppelgngers. Our analysis implies that chemical tagging in the strict sense, identifying birth siblings for typical disk stars through their abundance similarity alone, will not work with such data. However, our approach shows that abundances have extremely valuable information for probabilistic chemo-orbital modeling, and combined with velocities, we have identified new cluster members from the field.
AB - We explore to what extent stars within Galactic disk open clusters resemble each other in the high-dimensional space of their photospheric element abundances and contrast this with pairs of field stars. Our analysis is based on abundances for 20 elements, homogeneously derived from APOGEE spectra (with carefully quantified uncertainties of typically 0.03 dex). We consider 90 red giant stars in seven open clusters and find that most stars within a cluster have abundances in most elements that are indistinguishable (in a X2-sense) from those of the other members, as expected for stellar birth siblings. An analogous analysis among pairs of >1000 field stars shows that highly significant abundance differences in the 20 dimensional space can be established for the vast majority of these pairs, and that the APOGEE-based abundance measurements have high discriminating power. However, pairs of field stars whose abundances are indistinguishable even at 0.03 dex precision exist: ∼0.3% of all field star pairs and ∼1.0% of field star pairs at the same (solar) metallicity [Fe/H]=0±0.02. Most of these pairs are presumably not birth siblings from the same cluster, but rather doppelgngers. Our analysis implies that chemical tagging in the strict sense, identifying birth siblings for typical disk stars through their abundance similarity alone, will not work with such data. However, our approach shows that abundances have extremely valuable information for probabilistic chemo-orbital modeling, and combined with velocities, we have identified new cluster members from the field.
KW - Galaxy: abundances
KW - Galaxy: disk
KW - Galaxy: formation
KW - methods: statistical
KW - open clusters and associations: individual (abundances)
KW - stars: abundances
UR - http://www.scopus.com/inward/record.url?scp=85041951865&partnerID=8YFLogxK
U2 - 10.3847/1538-4357/aa9d8e
DO - 10.3847/1538-4357/aa9d8e
M3 - Article
AN - SCOPUS:85041951865
SN - 0004-637X
VL - 853
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
M1 - 198
ER -