Further Results from the Galactic O-Star Spectroscopic Survey: Rapidly Rotating Late ON Giants

Abstract

With new data from the Galactic O-Star Spectroscopic Survey, we confirm and expand the ONn category of late-O, nitrogen-enriched (N), rapidly rotating (n) giants. In particular, we have discovered two "clones" (HD 102415 and HD 117490) of one of the most rapidly rotating O stars previously known (HD 191423, "Howarth's Star"). We compare the locations of these objects in the theoretical HR Diagram to those of slowly rotating ON dwarfs and supergiants. All ON giants known to date are rapid rotators, whereas no ON dwarf or supergiant is; but all ON stars are small fractions of their respective spectral-type/luminosity-class/rotational subcategories. The ONn giants, displaying both substantial processed material and high rotation at an intermediate evolutionary stage, may provide significant information about the development of those properties. They may have preserved high initial rotational velocities or been spun up by TAMS core contraction; but alternatively and perhaps more likely, they may be products of binary mass transfer. At least some of them are also runaway stars.

18 pages, 2 figures, 2 tables; accepted for publication in the November 2011 issue of The Astronomical Journal

References in corpus (4)

• Physical Properties of Wolf-Rayet Stars
• The Galactic O-Star Spectroscopic Survey. I. Classification System and Bright Northern Stars in the Blue-Violet at R~2500
• The Galactic O-Star Spectroscopic Survey (GOSSS)
• Mixing of CNO-cycled matter in massive stars

Cited by in corpus (17)

• Pre-Supernova Evolution of Massive Single and Binary Stars
• The Galactic O-Star Spectroscopic Survey (GOSSS). II. Bright Southern Stars
• A Be-type star with a black hole companion
• The Galactic O-Star Spectroscopic Survey (GOSSS). III. 142 additional O-type systems
• The VLT-FLAMES Tarantula Survey XIV. The O-Type Stellar Content of 30 Doradus
• On the photometric detection of Internal Gravity Waves in upper main-sequence stars I. Methodology and application to CoRoT targets
• Discovery of two new Galactic candidate luminous blue variables with WISE
• A study of the effect of rotational mixing on massive stars evolution: surface abundances of Galactic O7-8 giant stars
• Spectral classification and properties of the O Vz stars in the Galactic O-Star Spectroscopic Survey (GOSSS)
• Chemical abundances of fast-rotating massive stars. I. Description of the methods and individual results
• Influence of Rotation on Stellar Evolution
• Quantitative spectroscopy of late O-type main-sequence stars with a hybrid non-LTE method
• The distance, rotation, and physical parameters of zeta Pup
• First constraints on the magnetic field strength in extra-Galactic stars: FORS2 observations of Of?p stars in the Magellanic Clouds
• Surface abundances of OC supergiants
• New Luminous ON Spectra from the Galactic O-Star Spectroscopic Survey
• Two New Rapidly-Rotating ON Stars Found With LAMOST