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Iron abundances from optical FeIII absorption lines in B-type stellar spectra
The role of optical FeIII absorption lines in B-type stars as ironabundance diagnostics is considered. To date, ultraviolet Fe lines havebeen widely used in B-type stars, although line blending can severelyhinder their diagnostic power. Using optical spectra, covering awavelength range ~3560-9200Å, a sample of Galactic B-typemain-sequence and supergiant stars of spectral types B0.5 to B7 areinvestigated. A comparison of the observed FeIII spectra of supergiants,and those predicted from the model atmosphere codes TLUSTY[plane-parallel, non-local thermodynamic equilibrium (LTE)], withspectra generated using SYNSPEC (LTE), and CMFGEN (spherical, non-LTE),reveal that non-LTE effects appear small. In addition, a sample ofmain-sequence and supergiant objects, observed with the Fiber-fedExtended Range Optical Spectrograph (FEROS), reveal LTE abundanceestimates consistent with the Galactic environment and previous opticalstudies. Based on the present study, we list a number of FeIIItransitions which we recommend for estimating the iron abundance fromearly B-type stellar spectra.

Walraven photometry of nearby southern OB associations
Homogeneous Walraven (VBLUW) photometry is presented for 5260 stars inthe regions of five nearby southern OB associations: Scorpio Centaurus(Sco OB2), Orion OB1, Canis Major OB1, Monoceros OB1, and Scutum OB2.Derived V and (B - V) in the Johnson system are included.

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Dades d'Observació i Astrometria

Constel·lació:Scorpius
Ascensió Recta:15h57m08.05s
Declinació:-21°34'50.0"
Magnitud Aparent:8.852
Distancia:75.019 parsecs
Moviment propi RA:-53.4
Moviment propi Dec:-25.4
B-T magnitude:9.508
V-T magnitude:8.907

Catàlegs i designacions:
Noms Propis   (Edit)
HD 1989HD 142768
TYCHO-2 2000TYC 6199-1836-1
USNO-A2.0USNO-A2 0675-14921553
HIPHIP 78123

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