期刊
ASTRONOMY & ASTROPHYSICS
卷 559, 期 -, 页码 -出版社
EDP SCIENCES S A
DOI: 10.1051/0004-6361/201321727
关键词
open clusters and associations: individual: Hyades; stars: luminosity function, mass function; stars: low-mass; stars: individual: 2MASSI J0230155+270406; stars: individual: 2MASS J05233822-1403022
资金
- German Research Foundation (DFG) [Sonderforschungsbereich SFB 881, OL 350/1-1]
- NAOC CAS
- Global Networks and Mobility Program of the University of Heidelberg [ZUK 49/1 TP14.8 Spurzem]
- NASA [HF-51255.01-A, NAS 5-26555]
- Space Telescope Science Institute
- National Aeronautics and Space Administration [NNX08AR22G]
- Planetary Science Division of the NASA Science Mission Directorate
- National Science Foundation [AST-1238877]
- Alfred P. Sloan Foundation
- National Science Foundation
- US Department of Energy Office of Science
- National Aeronautics and Space Administration
- Max-Planck Institute for Astronomy, Heidelberg
- Max Planck Institute for Extraterrestrial Physics, Garching
- Johns Hopkins University
- Durham University
- University of Edinburgh
- Queen's University Belfast
- Harvard-Smithsonian Center for Astrophysics
- Las Cumbres Observatory Global Telescope Network Incorporated
- National Central University of Taiwan
- Division Of Astronomical Sciences
- Direct For Mathematical & Physical Scien [1009749] Funding Source: National Science Foundation
Aims. The Hyades cluster is an ideal target to study the dynamical evolution of a star cluster over the entire mass range due to its intermediate age and proximity to the Sun. Methods. We wanted to extend the Hyades mass function towards lower masses down to 0.1 M-circle dot and to use the full three-dimensional spatial information to characterize the dynamical evolution of the cluster. Results. We performed a kinematic and photometric selection using the PPMXL and Pan-STARRS 1 sky surveys, to search for cluster members up to 30 pc from the cluster centre. We determined our detection efficiency and field star contamination rate to derive the cluster luminosity and mass functions down to masses of 0.1 M-circle dot. The thorough astrometric and photometric constraints minimized the contamination. A minimum spanning tree algorithm was used to quantify the mass segregation. Conclusions. We discovered 43 new Hyades member candidates with velocity perpendicular to the Hyades motion up to 2 km s(-1). They have mass estimates between 0.43 and 0.09 M-circle dot, for a total mass of 10 M-circle dot. This doubles the number of Hyades candidates with masses smaller than 0.15 M-circle dot. We provide an additional list of 11 possible candidates with velocity perpendicular to the Hyades motion up to 4 km s(-1). The cluster is significantly mass segregated. The extension of the mass function towards lower masses provided an even clearer signature than estimated in the past. We also identified as likely Hyades member an L0 dwarf previously assumed to be a field dwarf. Finally we question the membership of a number of previously published candidates, including a L2.5-type dwarf.
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