Israel, G. L.G. L.IsraelCampana, S.S.CampanaNegueruela, I.I.Negueruela2020-09-172020-09-172001-06-01https://hdl.handle.net/20.500.13025/30Astronomy and Astrophysics, v.371, p.1018-1023 (2001)We report on the identification of the optical/IR counterpart of the 29.5-s transient X-ray pulsar GS 1843+009. We re-analysed an archival ROSAT HRI observation of GS 1843+009, obtaining a new refined position. The optical and IR follow-up observations carried out for the new error circle allowed us to find a relatively faint (V=20.9) and variable early type reddened star (V-R=2.1). The optical spectra show the Balmer and Paschen series in emission, while the IR observations confirm the presence of a flux excess (H=13.2, J-H=0.54), suggesting that the star is surrounded by a circumstellar envelope. Spectroscopic and photometric data together indicate a B0-B2 IV-Ve spectral-type star located at a distance of >= 10 kpc confirming the Be-star/X-ray binary nature of GS 1843+009. Partially based on observations carried out at ESO, La Silla, Chile (65.H--0005).STARS INDIVIDUALGS 1843+009GS 1843+009HRIBINARIES GENERALSTARS PULSARS GENERALSTARS EMISSION-LINEBEX-RAYS STARS10.1051/0004-6361 20010417http://adsabs.harvard.edu/abs/2001A&A...371.1018I2001A&A...371.1018I