Vilnius Multicolor CCD Photometry of the Open Cluster NGC 752

Abstract

Abstract. We have performed multicolor CCD observations of the central area of NGC 752 to search for faint, low-mass members of this open cluster. Four 12 ′ ×12 ′ fields were taken on the 1.8 m Vatican Advanced Technology Telescope (Mt. Graham, Arizona) using a 4K CCD camera and eight intermediate-band filters of the Strömvil (Strömgren + Vilnius) system. In this paper we present a catalog of photometry for 405 stars down to the limiting magnitude V = 18.5, which contains V magnitudes and color indices of the Vilnius system, together with photometric determinations of spectral types, absolute magnitudes M V , interstellar reddening values E Y −V and metallicity parameters [Fe/H]. The good quality multicolor data made it possible to identify the locus of the lower main sequence to four magnitudes beyond the previous (photographic) limit. A relatively small number of photometric members identified at faint magnitudes seems to be indicative of actual dissolution of the cluster from the low-mass end.

The Metallicity Distribution and Hot Jupiter Rate of the Kepler Field: Hectochelle High-resolution Spectroscopy for 776 Kepler Target Stars

“…The effective temperatures are consistent in general on the range from 4500 K to 6500 K, with a standard deviation smaller than 100 K, although photometric T eff are generally slightly higher than the Hectochelle spectroscopic T eff . Previous studies on NGC 752 have suggested a range of possible ages from 1.2 Gyr to 1.9 Gyr (Bilir et al 2006;Bartašiūtė et al 2007) and a slightly sub-solar metallicity, so by assuming a 1.5-Gyr-old solar metallicity isochrone gives a systematic offset towards a younger and slightly more metal rich cluster. This in turn could result in overestimated photometric T eff s. In addition, spectroscopic measurements on T eff are known to be slightly lower than the photometric measurements, which we discuss in Section 5.…”

The chemical compositions and evolutionary status of red giants in the open cluster NGC 752

“…Dan94, Bartašiūtė et al 2007 andBartašiūtė et al 2011). We used the combined photometric data from Dan94, since the data from Bartašiūtė et al (2007) and Bartašiūtė et al (2011) do not include all the NGC 752 RG members present in our target list (Table 2). Figure 1 shows a comparison of the photometric data obtained by Dan94 to the latest set of PARSEC isochrones (Bressan et al (2012)).…”

“…Dan94 used both spectroscopic and photometric approaches to derive a mean cluster metallicity of [Fe/H] = −0.15 ± 0.05. From Vilnius photometry, Bartašiūtė et al (2007) derived [Fe/H] = −0.12 ± 0.03, and Bartašiūtė et al (2011) of NGC 752, and from 10 non-binary members they derived [Fe/H] = −0.06 ± 0.03. Finally, Heiter et al (2014) reported a mean metallicity of [Fe/H] = −0.02 ± 0.04, based on spectroscopic data gathered from 19 different sources.…”

“…Bartašiūtė et al (2007) conducted seven-color Vilnius photometry for NGC 752, and from the best isochrone match to the CMD they found (m − M )0 = 8.06 ± 0.03 (409±6 pc). Later, Bartašiūtė et al (2011) analyzed Vilnius multicolor photometry of NGC 752 with an expanded sample that extended down the main sequence to V ∼ = 18.5. Using the data of 70 photometric members, they derived (m−M )0 = 8.37±0.32 (472±72 pc), consistent with their prior estimate due to its larger uncertainty.…”

Radial velocities and metallicities from infrared Ca II triplet spectroscopy of open clusters

“…Carraro et al 1999;Vallenari et al 2000), and Vilnius (e.g. Bartašiūtė et al 2011;Zdanavičius et al 2011) photometric systems, often giving Based on observations made with the 2.5 Isaac Newton Telescope operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias. 1 The updated version of this catalog can be found at http://www.astro.iag.usp.br/~wilton/ rise to considerable differences among them and to those obtained from spectroscopy.…”