SIMBAD references

2022MNRAS.511.3113H - Mon. Not. R. Astron. Soc., 511, 3113-3124 (2022/April-2)

The nature of the Cygnus extreme B supergiant 2MASS J20395358+4222505.

HERRERO A., BERLANAS S.R., GIL DE PAZ A., COMERON F., PULS J., RAMIREZ ALEGRIA S., GARCIA M., LENNON D.J., NAJARRO F., SIMON-DIAZ S., URBANEJA M.A., GALLEGO J., CARRASCO E., IGLESIAS J., CEDAZO R., GARCIA VARGAS M.L., CASTILLO-MORALES A., PASCUAL S., CARDIEL N., PEREZ-CALPENA A., GOMEZ-ALVAREZ P. and MARTINEZ-DELGADO I.

Abstract (from CDS):

2MASS J20395358+4222505 is an obscured early B supergiant near the massive OB star association Cygnus OB2. Despite its bright infrared magnitude (Ks = 5.82) it has remained largely ignored because of its dim optical magnitude (B = 16.63, V = 13.68). In a previous paper, we classified it as a highly reddened, potentially extremely luminous, early B-type supergiant. We obtained its spectrum in the U, B and R spectral bands during commissioning observations with the instrument MEGARA at the Gran Telescopio CANARIAS. It displays a particularly strong Hα emission for its spectral type, B1 Ia. The star seems to be in an intermediate phase between supergiant and hypergiant, a group that it will probably join in the near (astronomical) future. We observe a radial velocity difference between individual observations and determine the stellar parameters, obtaining Teff = 24 000 K and log gc = 2.88 ± 0.15. The rotational velocity found is large for a B supergiant, v sin i = 110 ± 25 km s–1. The abundance pattern is consistent with solar, with a mild C underabundance (based on a single line). Assuming that J20395358+4222505 is at the distance of Cyg OB2, we derive the radius from infrared photometry, finding R = 41.2 ± 4.0 R, log(L/L) = 5.71 ± 0.04 and a spectroscopic mass of 46.5 ± 15.0 M. The clumped mass-loss rate (clumping factor 10) is very high for the spectral type, {dot}M = 2.4 x 10–6 M a–1. The high rotational velocity and mass-loss rate place the star at the hot side of the bi-stability jump. Together with the nearly solar CNO abundance pattern, they may also point to evolution in a binary system, J20395358+4222505 being the initial secondary.

Abstract Copyright: © 2022 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society

Journal keyword(s): stars: evolution - stars: individual: 2MASS J20395358+4222505 - stars: massive - supergiants - stars: winds, outflows

Simbad objects: 21

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2023.02.09-04:48:25

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