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Astron. Astrophys. 345, L1-L4 (1999)

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Letter to the Editor

The identification of the long-period X-ray pulsar 1WGA J1958.2+3232 with a Be-star/X-ray binary *

G.L. Israel **  1, S. Covino 2, V.F. Polcaro 3 and L. Stella[FORMULA]  1

1 Osservatorio Astronomico di Roma, Via Frascati 33, I-00040 Monteporzio Catone (Roma), Italy
2 Osservatorio Astronomico di Brera, Via E. Bianchi 46, I-23807 Merate (Lecco), Italy
3 Istituto di Astrofisica Spaziale, Area di Ricerca di Roma-Tor Vergata, Via Fosso del Cavaliere, I-00133 Roma, Italy

Received 24 February 1999 / Accepted 18 March 1999


We present the results of optical observations performed between May and September 1998 of the stars within the position error circle of the recently discovered [FORMULA]12 min pulsating X-ray source 1WGA J1958.2+3232. Based on photometry and slitless spectroscopy, we selected a likely optical counterpart, which was subsequently determined to be a mV=15.7 B0Ve star, the spectral properties of which are in good agreement with the X-ray results. The proposed optical counterpart shows several H, He and Fe emission-lines, while the interstellar absorption spectral features place the star at a distance of [FORMULA] 800 pc. The inferred X-ray luminosity for this distance is [FORMULA] 1033 erg s-1 in the 2-10 keV band. We conclude that 1WGA J1958.2+3232 is a likely new long-period low-luminosity accreting neutron star in a Be-star/X-ray binary system.

Key words: stars: binaries: general – stars: emission-line, Be – stars: neutron – stars: pulsars: individual: 1WGA J1958.2+3232 – X-rays: stars

* Based on data collected at the Astronomical Observatory of Loiano, Italy
** Affiliated to I.C.R.A.

Send offprint requests to: G.L. Israel (gianluca@coma.mporzio.astro.it)

© European Southern Observatory (ESO) 1999

Online publication: April 12, 1999