NGC2587: a sparse open cluster projected on to a populous star field

We present CCD photometry in the Johnson U, B and V and Kron–Cousins I passbands for the open cluster NGC 2587. The sample consists of 4406 stars reaching down to V∼ 21.0. We developed a new method to clean statistically the colour–magnitude diagrams. NGC 2587 appears to be a sparse, relatively bright open cluster, with a few tens of members projected on to a populous star field. The comparatively bright F7/8 II type star HD 70927, located close to the cluster centre, seems not to be a member. Our analysis suggests that NGC 2587 is slightly younger than the Hyades and probably of solar metallicity. A cluster radius of roughly 8 arcmin was estimated from the radial stellar density profile. From 18 probable cluster members with measured proper motions, we derive the following mean values for NGC 2587: μα=−4.3 ± 3.6 mas yr−1 and μδ=−2.5 ± 3.4 mas yr−1. Adopting the theoretical metal content Z= 0.02, which provides the best global fit, we derive a cluster age of 500+60−50. Simultaneously, colour excesses E(B−V) = 0.10 and E(V−I) = 0.15 and an apparent distance modulus of V−MV= 12.50 are obtained. The interstellar extinction in the cluster direction is found to follow the normal law. NGC 2587 is located at a distance of (2.70 ± 0.70) kpc from the Sun and ∼9.8 kpc from the Galactic centre.Fil: Piatti, Andres Eduardo. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Claria Olmedo, Juan Jose. Universidad Nacional de Cordoba. Observatorio Astronomico de Cordoba; ArgentinaFil: Ahumada, Andrea Veronica. Universidad Nacional de Cordoba. Observatorio Astronomico de Cordoba; Argentina. European Southern Observatory; Chil

Integrated spectral properties of 7 galactic open clusters

This paper presents flux-calibrated integrated spectra in the range 3600 - 9000 Å for 7 concentrated, relatively populous Galactic open clusters. We perform simultaneous estimates of age and foreground interstellar reddening by comparing the continuum distribution and line strengths of the cluster spectra with those of template cluster spectra with known parameters. For five clusters these two parameters have been determined for the first time (Ruprecht 144, BH 132, Pismis 21, Lyngå11 and BH 217), while the results here derived for the remaining two clusters (Hogg 15 and Melotte 105) show very good agreement with previous studies based mainly on colour-magnitude diagrams. We also provide metallicity estimates for six clusters from the equivalent widths of CaII triplet and TiO features. The present cluster sample improves the age resolution around solar metal content in the cluster spectral library for population synthesis. We compare the properties of the present sample with those of clusters in similar directions. Hogg 15 and Pismis 21 are among the most reddened clusters in sectors centered at l = 270° and l = 0°, respectively. Besides, the present results would favour an important dissolution rate of star clusters in these zones.Fil: Ahumada, Andrea Veronica. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; ArgentinaFil: Claria Olmedo, Juan Jose. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; ArgentinaFil: Bica, Eduardo. Universidade Federal do Rio Grande do Sul; BrasilFil: Piatti, Andres Eduardo. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentin

A Theoretical and Qualitative Approach to Evaluating Children’s Robot-Mediated Levels of Presence.

Each year, 2.5 million children in the US are homebound due to illness (NHIS, 2016; US Census Bureau, 2016). This paper explores the possible implications of being homebound for child development and well-being, drawing on Bronfenbrenner’s bioecological systems theory  of human development and Ryan and Deci’s self-determination theory. This paper also explores the potential role of robotic avatars and robot-mediated presence to provide homebound children with more appropriate developmental experiences. To better understand their robot-mediated developmental experiences, what is known about human development and human psychology in organic environments (i.e., bioecological systems theory, self-determination theory) is synthesized with concepts of presence theory from virtual environments. These theoretical supports form the foundation of a framework to evaluate the robot-mediated presence of homebound children. Findings from the first systematic, multi-case study on the robot-mediated presence of homebound children in schools provide empirical data to inform three identified levels of presence: co-present, cooperating, collaborating. This framework provides a first step to consistent evaluation of robot-mediated presence and engagement for this population. Understanding the social contexts and developmental needs of homebound children and how they can be achieved via robotic avatars will aid in developing more effective interventions for improved social supports and technological systems

Improvements on the fundamental parameters of the open cluster Tombaugh 1 through Washington system photometry

We present CCD photometry in the Washington system C and T1 passbands down to T1 ∼ 18.5 mag in the field of Tombaugh 1, a little studied open cluster located in the third Galactic quadrant. We measured T1 magnitudes and C −T1 colours for a total of 1351 stars distributed throughout an area of 13. 6 × 13. 6. A cluster radius of 4. 3 ± 0. 3 was estimated from star counts in 100-pixel a side boxes distributed throughout the entire observed field. Based on the best fits of isochrones computed by the Geneva group for Z = 0.008 to the T1 vs. C − T1 colour–magnitude diagram, we derive a colour excess E(C − T1) = 0.55 ± 0.10, equivalent to E(B − V) = 0.30 ± 0.05, a distance of (2.2 ± 0.5) kpc from the Sun and an age of 1.3 +0.1 −0.2 Gyr. The latter value is in good agreement with that derived from the independent metallicity δT1 index defined in Geisler et al. (1997, AJ, 114, 1920). An independent metallicity estimation using the [MT1 , (C − T1)0] plane with the standard giant branches of Geisler & Sarajedini (1999, AJ, 117, 308) yields [Fe/H] = −0.30 ± 0.25 dex, a value which lends support to the one obtained from the isochrone fit. Tombaugh 1 is then found to be a relatively metal-poor intermediate-age open cluster.Fil: Piatti, Andres Eduardo. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Claria Olmedo, Juan Jose. Universidad Nacional de Cordoba. Observatorio Astronomico de Cordoba; ArgentinaFil: Ahumada, Andrea Veronica. Universidad Nacional de Cordoba. Observatorio Astronomico de Cordoba; Argentin

NGC 6318: a young, highly reddened open cluster in the Galactic center direction

Presentamos fotometrıa CCD BVI del cumulo abierto NGC 6318. Recuentos estelares efectuados en la region del cumulo permiten estimar el radio angular de NGC 6318 en ∼ 8’. La comparacion de los diagramas CM con isocronas teoricas del grupo de Ginebra implica: E(B-V) = 1.20 ± 0.05, E(V-I) = 1.55 ± 0.10 y V-MV = 15.45 ± 0.35 (d = 2.1 ± 0.5 kpc) para log t = 8.20 (t = 1.6x108 anos) ˜ y Z = 0.020. Entre los cumulos conocidos en la direccion de NGC 6318, Havlen-Moffat 1 y BH 222 son los mas distantes, en tanto que aquellos ubicados entre 1 y 2 kpc del Sol est´an mas absorbidos que lo que deberıamos esperar si los mismos respetaran una ley de extinci´on cuasi-lineal.We present CCD BVI photometry for the open cluster NGC 6318. Star counts carried out in the cluster field yield an angular radius of 8.0' for NGC 6318. The comparison of the cluster CMDs with isochrones of the Geneva group yields E(B-V) = 1.20 + 0.05, E(V-I) = 1.55 + 0.10 and V-Mv = 15.45 + 0.35 (d = 2.1 + 0.5 kpc) for log t = 8.20 (t = 160 Myr) and Z = 0.020. Among the known clusters in the line-of-sight of NGC 6318, Havlen-Moffat 1 and BH 222 are the farthest ones, while those located between 1 and 2 kpc from the Sun appear to be more absorbed than those expected to follow a quasi-linear extinction law.Fil: Piatti, Andres Eduardo. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Claria Olmedo, Juan Jose. Universidad Nacional de Cordoba. Observatorio Astronomico de Cordoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ahumada, Andrea Veronica. Universidad Nacional de Cordoba. Observatorio Astronomico de Cordoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

The old open cluster Trumpler 5: a reddened, metal-poor, anticentre cluster

CCD observations in the Johnson V, Kron–Cousins I and the Washington system C and T1 passbands have been used to generate colour–magnitude diagrams (CMDs) reaching down to V ∼ 21.0 mag and T1 ∼ 19.0 for Trumpler 5, an old open cluster located towards the Galactic anticentre. Our data analysis confirms the existence of non-uniform extinction over the face of the cluster, the mean E(V − I) and E(C − T1) values being 0.80 ± 0.05 and 1.17 ± 0.15, respectively. Through comparison of the cluster CMDs with theoretical isochrones of the Geneva group, Washington Standard Giant Branches and measures of δV and δT1 indices, we derive the following values for the cluster apparent distance modulus, age, and metallicity: V − MV = 13.80 ± 0.30 (corresponding to a distance from the Sun of 2.4 ± 0.5 kpc and 0.04 kpc above the Galactic plane), t = 5.0 ± 0.5 Gyr and [Fe/H] = −0.30 ± 0.15. We estimate the cluster angular radius to be about 7.7 arcmin (= 5.4 pc) from star counts carried out within and outside the cluster field.Fil: Piatti, Andres Eduardo. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Claria Olmedo, Juan Jose. Universidad Nacional de Cordoba. Observatorio Astronomico de Cordoba; ArgentinaFil: Ahumada, Andrea Veronica. Universidad Nacional de Cordoba. Observatorio Astronomico de Cordoba; Argentin

Intermediate age Galactic open clusters: fundamental parameters of NGC 2627

Charge-coupled device (CCD) photometry in the Johnson V, Kron–Cousins I and Washington CMT1 systems is presented in the field of the poorly known open cluster NGC 2627. Four independent Washington abundance indices yield a mean cluster metallicity of [Fe/H] = −0.12 ± 0.08, which is compatible with the existence of a radial gradient in the Galactic disc. The resultant colour–magnitude diagrams indicate that the cluster is an intermediate-age object of 1.4 Gyr. Based on the best fits of the Geneva group’s isochrones to the (V, V − I) and (T 1, C − T 1) diagrams, we estimate E(V − I) = 0.25 ± 0.05 and V − MV = 11.80 ± 0.25 for log t = 9.15, and E(C − T 1) = 0.23 ± 0.07 and T 1−MT 1 = 11.85 ± 0.25 for log t = 9.10, respectively, assuming solar metal content. The derived reddening value E(C − T 1) implies E(B − V) = 0.12 ± 0.07 and a distance from the Sun of 2.0 ± 0.4 kpc. Using the WEBDA data base and the available literature, we re-examined the overall properties of all the open clusters with ages between 0.6 and 2.5 Gyr. We identified peaks of cluster formation at 0.7–0.8, 1.0–1.1, 1.6–1.7 and 2.0–2.1 Gyr, separated by relative quiescent epochs of ∼0.2–0.3 Gyr. We also estimated a radial abundance gradient of −0.08 ± 0.02, which is consistent with the most recent determinations for the Galactic disc, but no clear evidence for a gradient perpendicular to the Galactic plane is found.Fil: Piatti, Andres Eduardo. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Claria Olmedo, Juan Jose. Universidad Nacional de Cordoba. Observatorio Astronomico de Cordoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ahumada, Andrea Veronica. Universidad Nacional de Cordoba. Observatorio Astronomico de Cordoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Photometric and kinematic study of the Galactic open cluster NGC 2309

We have obtained CCD UBVIKC photometry for NGC 2309, a relatively poor open cluster (OC) projected onto a rich star field in Monoceros. Probable cluster members have been identified for the first time from sound photometric criteria. We have derived the angular radius and the fundamental cluster parameters. The resulting reddening and distance values place this object among the relatively most reddened and distant known OCs projected towards the direction of NGC 2309. A detailed version of this work can be seen in PASP, 122, 288 (2010).Hemos obtenido fotometría CCD UBVIKC para NGC 2309, un cúmulo abierto (CA) relativamente pobre en estrellas proyectado sobre un campo estelar densamente poblado en Monoceros. Probables miembros del cúmulo han sido identificados por vez primera vez a partir de s´olidos criterios fotométricos. Hemos derivado el radio angular y los parámetros fundamentales del cúmulo. Los valores resultantes del enrojecimiento y la distancia muestran que NGC 2309 es uno de los CAs conocidos relativamente m´as enrojecidos y distantes proyectados en la dirección de NGC 2309. Una versión detallada del trabajo puede verse en PASP, 122, 288 (2010).Fil: Piatti, Andres Eduardo. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Claria Olmedo, Juan Jose. Universidad Nacional de Cordoba. Observatorio Astronomico de Cordoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ahumada, Andrea Veronica. Universidad Nacional de Cordoba. Observatorio Astronomico de Cordoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Nuevos parámetros fundamentales de 5 cúmulos abiertos del tercer cuadrante galáctico: historia del gradiente radial de metalicidad en el disco

We present CCD UBVIKC photometry in the regions of the open clusters (OCs) Berkeley 26, Czernik 27, Melotte 72, NGC 2479 and BH 37. We present possible solutions for the cluster fundamental parameters by matching theoretical isochrones to the cleaned color-magnitude diagrams. Based on the results obtained for the current cluster sample and using the recently updated version of the Dias et al.’s (2002) OC Catalogue, different relationships between the positions in the Galaxy of known OCs, their ages and their metallicities are reexamined.Presentamos fotometrıa CCD UBVIKC en las regiones de los cumulos abiertos (CAs) Berkeley 26, Czernik 27, Melotte 72, NGC 2479 y BH 37. En base al ajuste de isocronas teoricas a los diagramas colormagnitud ”limpiados”, presentamos posibles soluciones para los parametros fundamentales de los cumulos. Usando los presentes resultados y la version actualizada del catalogo de CAs de Dias et al. (2002), reexaminamos diferentes relaciones entre las posiciones en la Galaxia de CAs conocidos, sus edades y sus metalicidades.Fil: Piatti, Andres Eduardo. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Claria Olmedo, Juan Jose. Universidad Nacional de Cordoba. Observatorio Astronomico de Cordoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ahumada, Andrea Veronica. Universidad Nacional de Cordoba. Observatorio Astronomico de Cordoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

First estimates of the fundamental parameters of the relatively bright Galactic open cluster NGC 5288

In this paper we present charge-coupled device (CCD) images in the Johnson B and V and Kron–Cousins I passbands for the previously unstudied open cluster NGC 5288. The sample consists of 15 688 stars reaching down to V ∼ 20.5. The cluster appears to have a relatively small but conspicuous nucleus and a low-density extended coronal region. Star counts carried out in 25 × 25 pixel2 boxes distributed throughout the whole observed field allowed us to estimate the angular core and corona radii as ∼1.3 and 6.3 arcmin, respectively. Our analysis suggests that NGC 5288 is moderately young and probably more metal-rich than the Sun. Adopting the theoretical metal content Z = 0.040, which provides the best global fit, we derive an age of 130+40 −30 Myr. Simultaneously, we have obtained colour excesses E(B − V) = 0.75 and E(V − I) = 0.95 and an apparent distance modulus V − MV = 14.00. The law of interstellar extinction in the cluster direction is found to be normal. NGC 5288 is located at 2.1 ± 0.3 kpc from the Sun beyond the Carina spiral feature and ∼7.4 kpc from the Galactic Centre. The cluster metallicity seems to be compatible with the cluster position in the Galaxy, given the recognized radial abundance gradient in the disc. For the first time, in this paper we determine the basic parameters for the open cluster NGC 5381, situated in the same direction as NGC 5288. This determination was reached by using CCD VI data published almost a decade ago by Pietrzy´nski et al. (1997) for NGC 5381. The properties of some open clusters aligned along the line of sight of NGC 5288 are examined. The properties of clusters of similar ages to NGC 5288 are also looked into. Evidence is presented that these did not form mainly along the spiral arms but rather in the thin Galactic disc (Z ∼ ±100 pc).Fil: Piatti, Andres Eduardo. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Claria Olmedo, Juan Jose. Universidad Nacional de Cordoba. Observatorio Astronomico de Cordoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ahumada, Andrea Veronica. Universidad Nacional de Cordoba. Observatorio Astronomico de Cordoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin