Astron. Astrophys. Suppl. Ser. 134, 525-536

The extremely young open cluster NGC 6611: Compiled catalogue, absorption map and the HR diagram

A.N. Belikov¹ - N.V. Kharchenko² - A.E. Piskunov¹ - E. Schilbach³

Send offprint request: E. Schilbach

1 - Institute of Astronomy of the Russian Acad. Sci. 48 Pyatnitskaya St., Moscow 109017, Russia
e-mail: abelikov@inasan.rssi.ru
2 - Main Astronomical Observatory, Golosiiv, 252650 Kiev, Ukraine
e-mail: nkhar@mao.kiev.ua
3 - Astrophysikalisches Institut Potsdam, An der Sternwarte 16, D-14482 Potsdam, Germany
e-mail: eschilbach@aip.de

Received May 29; accepted September 18, 1998

Abstract:

A compiled catalogue of astrometric and photometric data for about 2200 stars down to $V=16.8^{\rm m}$ is presented. The stars are located in an area with a radius of 22.8 arcmin around the extremely young open cluster NGC 6611 with the cluster center at ($\alpha,\delta)_{2000.0}=18^{\rm h}18^{\rm m}40^{\rm s},-13^\circ 47.1'$. The catalogue is based on new reductions of positions, proper motions, and of photometric data that have been published in this region and includes, among others, Hipparcos, AC/GSC and Tautenburg Schmidt plate observations. For the membership determination, spatial and proper motion distributions of stars in the region were analysed. An extinction map of the area and the cluster color-magnitude diagram down to $M_V=+1^{\rm m}$ were constructed. The distance of NGC 6611 was determined as $2.14 \pm 0.10$ kpc.

Key words: open clusters -- HR diagram