A probable pre-main sequence chemically peculiar star in the open cluster Stock 16

NETOPIL, M.; FOSSATI, L.; PAUNZEN, E.; ZWINTS, K.; PINTADO, O. I.; BAGNULO, S.

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2014 vol. 442 p. 3761 - 3768

0035-8711

We used the Ultraviolet and Visual Echelle Spectrograph of the ESO-Very Large Telescopeto obtain a high resolution and high signal-to-noise ratio spectrum of Stock 16-12, an earlytypestar which previous
a photometric observations suggest being a chemically peculiar(CP) star. We used spectral synthesis to perform a detailed abundance analysis obtaining aneffective temperature of 8400±400K, a surface gravity of 4.1±0.4, a microturbulence velocityof 3.4+0.7−0.3 kms−1, and a projected rotational velocity of 68±4 kms−1. We provide photometricand spectroscopic evidence showing the star is most likely a member of the young Stock16 open cluster (age 3?8Myr). The probable cluster membership, the star?s position in theHertzsprung-Russell diagram, and the found infrared excess strongly suggest the star is stillin the pre-main-sequence (PMS) phase. We used PMS evolutionary tracks to determine thestellar mass, which ranges between 1.95 and 2.3M⊙, depending upon the adopted spectroscopicor photometric data results. Similarly, we obtained a stellar age ranging between 4 and6Myr, in agreement with that of the cluster. Because the star?s chemical abundance patternresembles well that known of main sequence CP metallic line (Am) stars, the object sets importantconstraints to the diffusion theory. Additional spectroscopic and spectropolarimetricdata allowed us to conclude that the object is probably a single non-magnetic star.