scholarly journals Solving the distance discrepancy for the open cluster NGC 2453

2019 ◽  
Vol 626 ◽  
pp. A10 ◽  
Author(s):  
D. González-Díaz ◽  
C. Moni Bidin ◽  
E. Silva-Villa ◽  
G. Carraro ◽  
D. Majaess ◽  
...  
Keyword(s):  
Planetary Nebula ◽  
Open Cluster ◽  
Independent Method ◽  
Radial Velocities ◽  
Line Of Sight ◽  
Fundamental Parameters ◽  
Data Release ◽  
Cluster Distance ◽  
Ubvri Photometry ◽  
Good Agreement

Context. The open cluster (OC) NGC 2453 is of particular importance since it has been considered to host the planetary nebula (PN) NGC 2452, however their distances and radial velocities are strongly contested. Aims. In order to obtain a complete picture of the fundamental parameters of the OC NGC 2453, 11 potential members were studied. The results allowed us to resolve the PN NGC 2452 membership debate. Methods. Radial velocities for the 11 stars in NGC 2453 and the PN were measured and matched with Gaia data release 2 (DR2) to estimate the cluster distance. In addition, we used deep multi-band UBVRI photometry to get fundamental parameters of the cluster via isochrone fitting on the most likely cluster members, reducing inaccuracies due to field stars. Results. The distance of the OC NGC 2453 (4.7 ± 0.2 kpc) was obtained with an independent method solving the discrepancy reported in the literature. This result is in good agreement with an isochrone fitting of 40–50 Myr. On the other hand, the radial velocity of NGC 2453 (78 ± 3 km s−1) disagrees with the velocity of NGC 2452 (62 ± 2 km s−1). Our results show that the PN is a foreground object in the line of sight. Conclusions. Due to the discrepancies found in the parameters studied, we conclude that the PN NGC 2452 is not a member of the OC NGC 2453.

scholarly journals White dwarf-open cluster associations based on Gaia DR2

2020 ◽  
Vol 645 ◽  
pp. A13
Author(s):  
M. Prišegen ◽  
M. Piecka ◽  
N. Faltová ◽  
M. Kajan ◽  
E. Paunzen
Keyword(s):  
Open Cluster ◽  
Open Clusters ◽  
Photometric Data ◽  
Mass Relation ◽  
Physical Processes ◽  
Satellite Mission ◽  
Cluster Membership ◽  
Fundamental Parameters ◽  
Data Release ◽  
Gaia Dr2

Context. Fundamental parameters and physical processes leading to the formation of white dwarfs (WDs) may be constrained and refined by discovering WDs in open clusters (OCs). Cluster membership can be utilized to establish the precise distances, luminosities, ages, and progenitor masses of such WDs. Aims. We compile a list of probable WDs that are OC members in order to facilitate WD studies that are impractical or difficult to conduct for Galactic field WDs. Methods. We use recent catalogs of WDs and OCs that are based on the second data release of the Gaia satellite mission (GDR2) to identify WDs that are OC members. This crossmatch is facilitated by the astrometric and photometric data contained in GDR2 and the derived catalogs. Assuming that most of the WD members are of the DA type, we estimate the WD masses, cooling ages, and progenitor masses. Results. We have detected several new likely WD members and reassessed the membership of the literature WDs that had been previously associated with the studied OCs. Several of the recovered WDs fall into the recently reported discontinuity in the initial-final mass relation (IFMR) around Mi ∼ 2.0 M⊙, which allows for tighter constrains on the IFMR in this regime.

scholarly journals AAOmega radial velocities rule out current membership of the planetary nebula NGC 2438 in the open cluster M46

2008 ◽  
Vol 391 (1) ◽  
pp. 399-404 ◽  
Author(s):  
L. L. Kiss ◽  
Gy. M. Szabó ◽  
Z. Balog ◽  
Q. A. Parker ◽  
D. J. Frew
Keyword(s):  
Planetary Nebula ◽  
Open Cluster ◽  
Radial Velocities ◽  
Rule Out

scholarly journals A revised moving cluster distance to the Pleiades open cluster

2017 ◽  
Vol 598 ◽  
pp. A48 ◽  
Author(s):  
P. A. B. Galli ◽  
E. Moraux ◽  
H. Bouy ◽  
J. Bouvier ◽  
J. Olivares ◽  
...  
Keyword(s):  
Open Cluster ◽  
Space Mission ◽  
Cluster Method ◽  
Individual Stars ◽  
Long Baseline ◽  
Cluster Distance ◽  
Trigonometric Parallaxes ◽  
Point Search ◽  
Good Agreement

Context. The distance to the Pleiades open cluster has been extensively debated in the literature over several decades. Although different methods point to a discrepancy in the trigonometric parallaxes produced by the Hipparcos mission, the number of individual stars with known distances is still small compared to the number of cluster members to help solve this problem. Aims. We provide a new distance estimate for the Pleiades based on the moving cluster method, which will be useful to further discuss the so-called Pleiades distance controversy and compare it with the very precise parallaxes from the Gaia space mission. Methods. We apply a refurbished implementation of the convergent point search method to an updated census of Pleiades stars to calculate the convergent point position of the cluster from stellar proper motions. Then, we derive individual parallaxes for 64 cluster members using radial velocities compiled from the literature, and approximate parallaxes for another 1146 stars based on the spatial velocity of the cluster. This represents the largest sample of Pleiades stars with individual distances to date. Results. The parallaxes derived in this work are in good agreement with previous results obtained in different studies (excluding Hipparcos) for individual stars in the cluster. We report a mean parallax of 7.44 ± 0.08 mas and distance of 134.4+2.9-2.8 pc that is consistent with the weighted mean of 135.0 ± 0.6 pc obtained from the non-Hipparcos results in the literature. Conclusions. Our result for the distance to the Pleiades open cluster is not consistent with the Hipparcos catalog, but favors the recent and more precise distance determination of 136.2 ± 1.2 pc obtained from Very Long Baseline Interferometry observations. It is also in good agreement with the mean distance of 133 ± 5 pc obtained from the first trigonometric parallaxes delivered by the Gaia satellite for the brightest cluster members in common with our sample.

Radial Velocities, Binarity, and Kinematic Membership in the Open Cluster NGC 2516

2000 ◽  
Vol 119 (5) ◽  
pp. 2296-2302 ◽  
Author(s):  
Jorge Federico González ◽  
Emilio Lapasset
Keyword(s):  
Open Cluster ◽  
Radial Velocities

scholarly journals The five axes of the Turtle: symmetry and asymmetry in NGC 6210

2021 ◽  
Author(s):  
William J Henney ◽  
J A López ◽  
Ma T García-Díaz ◽  
M G Richer
Keyword(s):  
Planetary Nebula ◽  
Morphological Study ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Line Of Sight ◽  
Velocity Mapping ◽  
High Ionization ◽  
Motion Measurements ◽  
Five Axes ◽  
Triple Star

Abstract We carry out a comprehensive kinematic and morphological study of the asymmetrical planetary nebula: NGC 6210, known as the Turtle. The nebula’s spectacularly chaotic appearance has led to proposals that it was shaped by mass transfer in a triple star system. We study the three-dimensional structure and kinematics of its shells, lobes, knots, and haloes by combining radial velocity mapping from multiple long-slit spectra with proper motion measurements from multi-epoch imaging. We find that the nebula has five distinct ejection axes. The first is the axis of the bipolar, wind-blown inner shell, while the second is the axis of the lop-sided, elliptical, fainter, but more massive intermediate shell. A further two axes are bipolar flows that form the point symmetric, high-ionization outer lobes, all with inclinations close to the plane of the sky. The final axis, which is inclined close to the line of sight, traces collimated outflows of low-ionization knots. We detect major changes in outflow directions during the planetary nebula phase, starting at or before the initial ionization of the nebula 3500 years ago. Most notably, the majority of redshifted low-ionization knots have kinematic ages greater than 2000 years, whereas the majority of blueshifted knots have ages younger than 2000 years. Such a sudden and permanent 180-degree flip in the ejection axis at a relatively late stage in the nebular evolution is a challenge to models of planetary nebula formation and shaping.

scholarly journals The bimodal [Mg/Fe] versus [Fe/H] bulge sequence as revealed by APOGEE DR14

2019 ◽  
Vol 626 ◽  
pp. A16 ◽  
Author(s):  
A. Rojas-Arriagada ◽  
M. Zoccali ◽  
M. Schultheis ◽  
A. Recio-Blanco ◽  
G. Zasowski ◽  
...  
Keyword(s):  
Fundamental Parameters ◽  
Elemental Abundances ◽  
Data Release ◽  
Bulge Region ◽  
Solar Metallicity ◽  
Inner Region ◽  
Clean Sample ◽  
Metallicity Distribution ◽  
Single Sequence

Context. The Galactic bulge has a bimodal metallicity distribution function: different kinematic, spatial, and, potentially, age distributions characterize the metal-poor and metal-rich components. Despite this observed dichotomy, which argues for different formation channels for those stars, the distribution of bulge stars in the α-abundance versus metallicity plane has been found so far to be a rather smooth single sequence. Aims. We use data from the fourteenth data release of the APOGEE spectroscopic survey (DR14) to investigate the distribution in the Mg abundance (as tracer of the α-elements)-versus-metallicity plane of a sample of stars selected to be in the inner region of the bulge. Methods. A clean sample has been selected from the DR14 using a set of data- and pipeline-flags to ensure the quality of their fundamental parameters and elemental abundances. An additional selection made use of computed spectro-photometric distances to select a sample of likely bulge stars as those with RGC ≤ 3.5 kpc. We adopt magnesium abundance as an α-abundance proxy for our clean sample as it has been proven to be the most accurate α-element as determined by ASPCAP, the pipeline for data products from APOGEE spectra. Results. From the distribution of our bulge sample in the [Mg/Fe]-versus-[Fe/H] plane, we found that the sequence is bimodal. This bimodality is given by the presence of a low-Mg sequence of stars parallel to the main high-Mg sequence over a range of ∼0.5 dex around solar metallicity. The two sequences merge above [Fe/H] ∼ 0.15 dex into a single sequence whose dispersion in [Mg/Fe] is larger than either of the two sequences visible at lower metallicity. This result is confirmed when we consider stars in our sample that are inside the bulge region according to trustworthy Gaia DR2 distances.

scholarly journals Tidal Circularization Among the Close Binaries in M67

1992 ◽  
Vol 151 ◽  
pp. 471-472
Author(s):  
David W. Latham ◽  
Robert D. Mathieu ◽  
Alejandra A. E. Milone ◽  
Robert J. Davis
Keyword(s):  
Main Sequence ◽  
Open Cluster ◽  
Radial Velocities ◽  
Spectroscopic Binaries ◽  
Close Binaries ◽  
To Come ◽  
Mirror Telescope

In 1971 Roger Griffin and Jim Gunn began monitoring the radial velocities of most of the members brighter than the main-sequence turnoff in the old open cluster M67, primarily using the 200-inch Hale Telescope. In 1982 the torch was passed to Dave Latham and Bob Mathieu, who began monitoring many of the same stars with the 1.5-meter Tillinghast Reflector and the Multiple-Mirror Telescope on Mt. Hopkins. We have successively combined these two sets of data, plus some additional CORAVEL velocities kindly provided by Michel Mayor, to obtain 20 years of time coverage (e.g. Mathieu et al. 1986). Among the stars brighter than magnitude V = 12.7 we have already published orbits for 22 spectroscopic binaries (Mathieu et al. 1990). At Mt. Hopkins an extension of this survey to many of the cluster members down to magnitude V = 15.5 has already yielded thirteen additional orbital solutions, with the promise of many more to come.

scholarly journals Refining the true parameters of the open cluster NGC 4852

2009 ◽  
Vol 5 (S266) ◽  
pp. 539-539
Author(s):  
Gladys Solivella ◽  
Edgard Giorg ◽  
Rubén Vázquez ◽  
Giovanni Carraro
Keyword(s):  
Emission Line ◽  
Open Cluster ◽  
Open Clusters ◽  
Occurrence Rate ◽  
Hot Stars ◽  
Cluster Area ◽  
Young Object ◽  
Cluster Distance ◽  
Be Star ◽  
Compact Cluster

AbstractNGC 4852 is a moderately compact cluster centered at α2000 = 13 : 00 : 09; δ = −59 : 36 : 48, located near the center of an Hα superring. This cluster forms part of an extended region including young stellar aggregates inside a circle with a radius of 3 degrees, where many show an abundance of emission line stars. In the field of this cluster, two stars of known type exist: Wray 15–1039 (emission-line object) and CD −58:4845 (emission-line star). We do not yet know whether the Be phase is transient or whether it is just what randomly happens in some hot stars. It appears that Be star may be found even in clusters as old as 70 Myr with a high occurrence rate in clusters of 25–27 Myr old. A recent photometric survey in NGC 4852 down to V = 22 – 23 mag established that NGC 4852 is about 200 – 250 Myr old, located at 1.1 kpc from the Sun and with a mean E(B − V) = 0.45 mag. Since the presence of potential Be-type stars in the cluster area suggests it may be a very young object instead of moderately old, we decided to carry out spectroscopy for 33 selected stars and CCD UBVI photometry for the bright objects in the cluster area. This way, we attempt to clarify their evolutionary state and include them in the framework of emission-line stars and open clusters. From our analysis, we agree with the cluster distance and reddening determined by earlier studies, but we derive that the age of NGC 4852 is younger than 40 Myr.

scholarly journals Gaia Early Data Release 3: Updated radial velocities from Gaia DR2

2021 ◽  
Author(s):  
G. M. Seabroke ◽  
C. Fabricius ◽  
D. Teyssier ◽  
P. Sartoretti ◽  
D. Katz ◽  
...  
Keyword(s):  
Radial Velocities ◽  
Early Data ◽  
Data Release ◽  
Gaia Dr2
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