an unusually solar-like twin, and the virtue of differential spectroscopy in galactic studies
DESCRIPTION
An unusually solar-like twin, and the virtue of differential spectroscopy in Galactic studies. Bengt Gustafsson Dept of Astronomy and Astrophysics Uppsala University. Solar Twins. M67. VandenBerg et al. Weiss. M67-1194. Pasquini et al. (2008) Solar-twin candidates in M67. M67-1194. - PowerPoint PPT PresentationTRANSCRIPT
An unusually solar-like twin, and the virtue of differential spectroscopy in Galactic studies
Bengt Gustafsson
Dept of Astronomy and Astrophysics
Uppsala University
Solar Twins
M67
VandenBerg et al.
Weiss
M67-1194
M67-1194
Pasquini et al. (2008)Solar-twin candidates in M67
M67-1194 Sun diff
(Å)
• Excitation of Fe I + H => 5780 ± 20 K • Fe I/Fe II + MgIb => log g = 4.44 ± 0.05 (cgs) t = 0.95 km/s• [Fe/H] = 0.023 ± 0.015
Age• Isochrones (Teff vs log g) by VandenBerg (2010): 4.2 ± 0.3 Gyr
If Y is different by 0.01 => 0.2 Gyr
• C.f. photometry,Yadav et al. (2008):3.5 - 4.8 Gyr
+ Meléndez et al. (2009)
• M67-1194
+ Meléndez et al. (2009)
• M67-1194
< 6% chance!