STELLAR BORON ABUNDANCES NEAR THE MAIN-SEQUENCE TURNOFF OF THE OPEN CLUSTER NGC 3293 AND IMPLICATIONS FOR THE EFFICIENCY OF ROTATIONALLY DRIVEN MIXING IN STELLAR ENVELOPES
- Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
- ESA–European Space Astronomy Centre, Camino Bajo del Castillo, s/n., Urb. Villafranca del Castillo, E-28692 Villanueva de la Cañada, Madrid (Spain)
- Argelander Institute for Astronomy, University of Bonn, Auf dem Hügel 71, D-53121 Bonn (Germany)
- University of Vienna Department of Astrophysics, Türkenschanzstrasse 17, A-1180, Vienna (Austria)
Spectra from the Hubble Space Telescope Cosmic Origins Spectrograph and the Space Telescope Imaging Spectrograph covering the B iii resonance line have been obtained for 10 early-B stars near the turnoff of the young Galactic open cluster NGC 3293. This is the first sample of boron abundance determinations in a single, clearly defined population of early-B stars that also covers a substantial range of projected rotational velocities. In most of these stars we detect partial depletion of boron at a level consistent with that expected for rotational mixing in single stars, but inconsistent with expectations for depletion from close binary evolution. However, our results do suggest that the efficiency of rotational mixing is at or slightly below the low end of the range predicted by the available theoretical calculations. The two most luminous targets observed have a very large boron depletion and may be the products of either binary interactions or post-main-sequence evolution.
- OSTI ID:
- 22666207
- Journal Information:
- Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 824; ISSN ASJOAB; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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