Astronomy and Astrophysics – Astrophysics
Scientific paper
2004-06-04
Astrophys.J. 610 (2004) L25-L28
Astronomy and Astrophysics
Astrophysics
12 pages, 3 figures, accepted for publication in ApJ Letters
Scientific paper
10.1086/423034
We report for the first time Na and O abundances from high-resolution, high S/N echelle spectra of 20 red giants in NGC 2808, taken as part of the Science Verification program of the FLAMES multi-object spectrograph at the ESO VLT. In these stars, spanning about 3 mag from the red giant branch (RGB) tip, large variations are detected in the abundances of oxygen and sodium, anticorrelated with each other; this is a well known evidence of proton-capture reactions at high temperatures in the ON and NeNa cycles. One star appears super O-poor; if the extension of the Na-O anticorrelation is confirmed, NGC 2808 might reach O depletion levels as large as those of M 13. This result confirms our previous findings based on lower resolution spectra (Carretta et al. 2003) of a large star-to-star scatter in proton capture elements at all positions along the RGB in NGC 2808, with no significant evolutionary contribution. Finally, the average metallicity for NGC 2808 is [Fe/H]= -1.14 +/- 0.01 dex (rms=0.06) from 19 stars.
Bragaglia Angela
Cacciari Carla
Carretta Eugenio
No associations
LandOfFree
Star-to-star Na and O abundance variations along the red giant branch in NGC 2808 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Star-to-star Na and O abundance variations along the red giant branch in NGC 2808, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Star-to-star Na and O abundance variations along the red giant branch in NGC 2808 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-59041