NGC 2401: A template of the Norma-Cygnus Arm's young population in the Third Galactic Quadrant

Abstract

Based on a deep optical CCD (UBV(RI)_C) photometric survey and on the Two-Micron All-Sky-Survey (2MASS) data we derived the main parameters of the open cluster NGC 2401. We found this cluster is placed at 6.3 $\pm$ 0.5 kpc (V_O - M_V = 14.0 \pm 0.2) from the Sun and is 25 Myr old, what allows us to identify NGC 2401 as a member of the young population belonging to the innermost side of the extension of the Norma-Cygnus spiral--arm in the Third Galactic Quadrant. A spectroscopic study of the emission star LSS 440 that lies in the cluster area revealed it is a B0Ve star; however, we could not confirm it is a cluster member. We also constructed the cluster luminosity function (LF) down to $V\sim 22$ and the cluster initial mass function (IMF) for all stars with masses above $M \sim 1-2 M_{\sun}$. It was found that the slope of the cluster IMF is $x\approx 1.8\pm 0.2$. The presence of a probable PMS star population associated to the cluster is weakly revealed.

arXiv comment10 paginas, 11 eps figures, accepted for publication in MNRAS

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Cited by in corpus (8)

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• Photometry of a Galactic field at l = 232, b = -6. The old open cluster Auner 1, the Norma-Cygnus spiral arm and the signature of the warped Galactic Thick Disk
• Stellar populations in the Canis Major over-density
• Extracting parameters from Colour-Magnitude Diagrams
• GeMS in the Outer Galaxy: Near-Infrared Imaging of Three Young Clusters at Large Galactic Radii
• The Distribution of Main Sequence and Pre-Main Sequence Stars in the Young Anticenter Cluster NGC 2401