scholarly journals The Cluster AgeS Experiment (CASE) – VIII. Age and distance of the Globular Cluster 47 Tuc from the analysis of two detached eclipsing binaries

2020 ◽  
Vol 492 (3) ◽  
pp. 4254-4267 ◽  
Author(s):  
I B Thompson ◽  
A Udalski ◽  
A Dotter ◽  
M Rozyczka ◽  
A Schwarzenberg-Czerny ◽  
...  
Keyword(s):  
Globular Cluster ◽  
Orbital Period ◽  
Surface Brightness ◽  
Eclipsing Binaries ◽  
Helium Abundance ◽  
Eccentric Orbit ◽  
Photometric And Spectroscopic Observations ◽  
Magnitude Diagram ◽  
The Masses ◽  
Gaia Dr2

ABSTRACT We use photometric and spectroscopic observations of the eclipsing binary E32 in the globular cluster 47 Tuc to derive the masses, radii, and luminosities of the component stars. The system has an orbital period of 40.9 d, a markedly eccentric orbit with e = 0.24, and is shown to be a member of or a recent escaper from the cluster. We obtain $M_{\rm p} = 0.862\pm 0.005 \, \mathrm{M}_\odot$, $R_{\rm p} = 1.183\pm 0.003 \, \mathrm{R}_\odot$, $L_{\rm p} = 1.65\pm 0.05 \, \mathrm{L}_\odot$ for the primary and $M_{\rm s} = 0.827\pm 0.005 \, \mathrm{M}_\odot$, $R_{\rm s} = 1.004\pm 0.004 \, \mathrm{R}_\odot$, $L_{\rm s} = 1.14\pm 0.04\, \mathrm{L}_\odot$ for the secondary. Based on these data and on an earlier analysis of the binary V69 in 47 Tuc, we measure the distance to the cluster from the distance moduli of the component stars, and, independently, from a colour – surface brightness calibration. We obtain 4.55 ± 0.03 and 4.50 ± 0.07 kpc, respectively – values compatible within 1$\, \sigma$ with recent estimates based on Gaia DR2 parallaxes. By comparing the M–R diagram of the two binaries and the colour–magnitude diagram of 47 Tuc to Dartmouth model isochrones we estimate the age of the cluster to be 12.0 ± 0.5 Gyr, and the helium abundance of the cluster to be Y ≈ 0.25.

scholarly journals Detailed study of the Milky Way globular cluster Laevens 3

2019 ◽  
Vol 490 (2) ◽  
pp. 1498-1508
Author(s):  
Nicolas Longeard ◽  
Nicolas Martin ◽  
Rodrigo A Ibata ◽  
Michelle L M Collins ◽  
Benjamin P M Laevens ◽  
...  
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
Milky Way ◽  
Rr Lyrae Stars ◽  
Rr Lyrae ◽  
Magnitude Diagram ◽  
Mass Segregation ◽  
Stellar Properties ◽  
Lyrae Stars ◽  
Gaia Dr2

ABSTRACT We present a photometric and spectroscopic study of the Milky Way satellite Laevens 3. Using MegaCam/Canada–France–Hawaii Telescope $g$ and $i$ photometry and Keck II/DEIMOS multi-object spectroscopy, we refine the structural and stellar properties of the system. The Laevens 3 colour–magnitude diagram shows that it is quite metal-poor, old ($13.0 \pm 1.0$ Gyr), and at a distance of $61.4 \pm 1.0$ kpc, partly based on two RR Lyrae stars. The system is faint ($M_V = -2.8^{+0.2}_{-0.3}$ mag) and compact ($r_h = 11.4 \pm 1.0$ pc). From the spectroscopy, we constrain the systemic metallicity (${\rm [Fe/H]}_\mathrm{spectro} = -1.8 \pm 0.1$ dex) but the metallicity and velocity dispersions are both unresolved. Using Gaia DR2, we infer a mean proper motion of $(\mu _\alpha ^*,\mu _\delta)=(0.51 \pm 0.28,-0.83 \pm 0.27)$ mas yr−1, which, combined with the system’s radial velocity ($\langle v_r\rangle = -70.2 \pm 0.5 {\rm \, km \,\, s^{-1}}$), translates into a halo orbit with a pericenter and apocenter of $40.7 ^{+5.6}_{-14.7}$ and $85.6^{+17.2}_{-5.9}$ kpc, respectively. Overall, Laevens 3 shares the typical properties of the Milky Way’s outer halo globular clusters. Furthermore, we find that this system shows signs of mass segregation that strengthens our conclusion that Laevens 3 is a globular cluster.

scholarly journals Testing Systematics of Gaia DR2 Parallaxes with Empirical Surface Brightness: Color Relations Applied to Eclipsing Binaries

2019 ◽  
Vol 872 (1) ◽  
pp. 85 ◽  
Author(s):  
Dariusz Graczyk ◽  
Grzegorz Pietrzyński ◽  
Wolfgang Gieren ◽  
Jesper Storm ◽  
Nicolas Nardetto ◽  
...  
Keyword(s):  
Surface Brightness ◽  
Eclipsing Binaries ◽  
Gaia Dr2

scholarly journals Spectroscopic and photometric study of two B-type pulsators in eclipsing systems

2013 ◽  
Vol 9 (S301) ◽  
pp. 403-404
Author(s):  
Dominik Drobek ◽  
Andrzej Pigulski
Keyword(s):  
Time Series ◽  
Binary Systems ◽  
Progress Report ◽  
Eclipsing Binaries ◽  
Photometric Study ◽  
Pulsating Stars ◽  
Seismic Modelling ◽  
Photometric And Spectroscopic Observations ◽  
The Masses ◽  
Precise Time

AbstractPulsating stars in eclipsing binary systems play an important role in asteroseismology. The combination of their spectroscopic and photometric orbital solutions can be used to determine, or at least to constrain, the masses and radii of components. To successfully perform any seismic modelling of a star, one has to identify at least some of the detected modes, which requires precise time-series photometric and spectroscopic observations. This work presents a progress report on the analysis of two β Cephei-type stars in eclipsing binaries: HD 101794 (V916 Cen) and HD 167003 (V4386 Sgr).

scholarly journals Study of Eclipsing Binary and Multiple Systems in OB Associations IV: Cas OB6 Member DN Cas

2016 ◽  
Vol 33 ◽  
Author(s):  
V. Bakış ◽  
H. Bakış ◽  
S. Bilir ◽  
Z. Eker
Keyword(s):  
Orbital Period ◽  
Early Type ◽  
Eccentric Orbit ◽  
Period Analysis ◽  
Multiple Systems ◽  
Spectroscopic Binary ◽  
Short Period ◽  
Synchronous Rotation ◽  
The Masses ◽  
Absolute Parameters

AbstractAn early-type, massive, short-period ($P_{\text{orb}}=2^d.310951$) eclipsing spectroscopic binary DN Cas has been re-visited with new spectral and photometric data. The masses and radii of the components have been obtained as $M_1=19.04\pm 0.07\,\text{M}_\odot$, $M_2=13.73\pm 0.05\,\text{M}_\odot$ and $R_1=7.22\pm 0.06\,\text{R}_\odot$, $R_2=5.79\pm 0.06\,\text{R}_\odot$, respectively. Both components present synchronous rotation ($V_{\text{rot}1}=160\,\text{km } \text{s}^{-1}$, $V_{\text{rot}2}=130\ \text{km} \,\text{s}^{-1}$) with their orbit. Orbital period analysis yielded a physically bound additional component in the system with a minimum mass of $M_3=0.88\,\text{M}_\odot$ orbiting in an eccentric orbit (e = 0.37 ± 0.2) with an orbital period of P12 = 42 ± 9 yr. High precision absolute parameters of the system allowed us to derive a distance to DN Cas as 1.7 ± 0.2 kpc which locates the system within the borders of the Cas OB6 association (d = 1.8 kpc). The space velocities and the age of DN Cas are in agreement with those of Cas OB6. The age of DN Cas (τ = 3–5 Myr) is found to be 1–2 Myr older than the embedded clusters (IC 1795, IC 1805, and IC 1848) in the Cas OB6 association, which implies a sequential star formation in the association.

scholarly journals The distance to the Small Magellanic Cloud from eclipsing binaries

2012 ◽  
Vol 8 (S289) ◽  
pp. 222-225 ◽  
Author(s):  
Dariusz Graczyk ◽  
Grzegorz Pietrzyński ◽  
Bogumił Pilecki ◽  
Ian B. Thompson ◽  
Wolfgang Gieren ◽  
...  
Keyword(s):  
Binary System ◽  
Systematic Error ◽  
Orbital Period ◽  
Surface Brightness ◽  
Magellanic Cloud ◽  
Eclipsing Binaries ◽  
Distance Modulus ◽  
Small Magellanic Cloud ◽  
Eclipsing Binary ◽  
Long Period

AbstractA preliminary distance etimate to SMC 108.1.14904, a long-period eclipsing binary in the Small Magellanic Cloud, is presented. The binary system contains two bright, non-active G-type giants. Its orbital period is 185 days and the orbit is circular. Using surface brightness calibration, we obtain a distance modulus to the system of (m-M)= 19.02 ± 0.04 (statistical) ± 0.05 (systematic) mag, where the systematic error is dominated by uncertainties in the surface brightness calibration. This is a second eclipsing binary in the SMC analysed by our team.

scholarly journals The disruption of the low-mass globular cluster E 3

2020 ◽  
Vol 499 (2) ◽  
pp. 2157-2161
Author(s):  
Julio A Carballo-Bello ◽  
Ricardo Salinas ◽  
Andrés E Piatti
Keyword(s):  
Globular Cluster ◽  
Surface Brightness ◽  
Galactic Centre ◽  
Proper Motions ◽  
Tidal Disruption ◽  
Low Surface Brightness ◽  
Low Mass ◽  
Important Amount ◽  
Tidal Tails ◽  
Gaia Dr2

ABSTRACT We use Gaia DR2 photometry and proper motions to search for the hypothetical tidal tails of the Galactic globular cluster E 3. Using a modified version of a classical decontamination procedure, we are able to identify the presence of an extended structure emerging from the cluster up to r ∼ 1 deg from its centre, thus suggesting that this poorly studied cluster is undergoing a tidal disruption process. These low surface brightness structures are aligned with the direction to the Galactic centre, as expected for a cluster close to its perigalacticon. Different scenarios to explain the important amount of mass lost by this cluster are discussed.

scholarly journals The Mass-Luminosity Relation From Binaries

1998 ◽  
Vol 11 (1) ◽  
pp. 419-420
Author(s):  
David W. Latham
Keyword(s):  
Eclipsing Binaries ◽  
M Dwarfs ◽  
Direct Measurements ◽  
Nearby Stars ◽  
The Masses ◽  
Stellar Masses ◽  
M Dwarf ◽  
Magnitude Difference ◽  
Astrometric Binaries ◽  
Better Than

What is known about the masses of main-sequence stars from the analysis of binary orbits? Double-lined eclipsing binaries are the main source of very precise stellar masses and radii (e.g. Andersen 1997), contributing more than 100 determinations with better than 2% precision over the range 0.6 to 20 Mʘ. For lower-mass stars we are forced to turn to nearby systems with astrometric orbits (e.g. Henry et al. 1993). Not only is the number of good mass determinations from such systems smaller, but also the precision is generally poorer. We are approaching an era when interferometers should have a major impact by supplying good astrometric orbits for dozens of double-lined systems. Already we are beginning to see the sorts of results to expect from this (e.g. Torres et al. 1997). Figure 1. Mass vs. absolute V magnitude for eclipsing binaries (circles) and nearby astrometric binaries (squares) Figure 1 is an updated version of a diagram presented by Henry et al. (1993, their Figure 2). It shows the general run of mass determinations from about 10 Mʘ down to the substellar limit near 0.075 Mʘ. Ninety of the points in Figure 1 are for eclipsing binary masses from Andersen’s review (1991) and are plotted as open circles. The results for eclipsing binaries published since 1991 are plotted as 30 filled circles, adopting the same limit of 2% for the mass precision. In most cases the uncertainties are similar to the size of the symbols. Especially noteworthy is the pair of new points for CM Draconis (Metcalfe et al. 1996) with masses near 0.25 Mʘ. Together with the points for YY Geminorum near 0.6 Mʘ, these are the only M dwarfs that have precise mass determinations. For the most part we are forced to rely on nearby stars with astrometric orbits, to fill in the M dwarf region of the diagram. We have used filled squares in Figure 1 for 29 such systems from Henry et al. (1993), updated using 14 new parallaxes from Hipparcos and 4 from the new Yale Parallax Catalog (1995). Gliese 508 is not included, because it is now known to be a triple, while Gliese 67AB, 570BC, and 623AB are not included because there are not yet any direct measurements of the V magnitude difference for these systems.

scholarly journals The Surface Brightness Fluctuations and Globular Cluster Population of NGC 4478

1997 ◽  
Vol 483 (2) ◽  
pp. 745-753 ◽  
Author(s):  
Eric H. Neilsen, Jr. ◽  
Zlatan I. Tsvetanov ◽  
Holland C. Ford
Keyword(s):  
Globular Cluster ◽  
Surface Brightness ◽  
Surface Brightness Fluctuations

scholarly journals Gemini/Phoenix H-band analysis of the globular cluster AL 3

2021 ◽  
Vol 648 ◽  
pp. A16
Author(s):  
B. Barbuy ◽  
H. Ernandes ◽  
S. O. Souza ◽  
R. Razera ◽  
T. Moura ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Wavelength Range ◽  
Globular Cluster ◽  
Spectral Region ◽  
Wavelength Region ◽  
Individual Stars ◽  
Synthetic Spectra ◽  
Cool Stars ◽  
Magnitude Diagram ◽  
The Phoenix

Context. The globular cluster AL 3 is old and located in the inner bulge. Three individual stars were observed with the Phoenix spectrograph at the Gemini South telescope. The wavelength region contains prominent lines of CN, OH, and CO, allowing the derivation of C, N, and O abundances of cool stars. Aims. We aim to derive C, N, O abundances of three stars in the bulge globular cluster AL 3, and additionally in stars of NGC 6558 and HP 1. The spectra of AL 3 allows us to derive the cluster’s radial velocity. Methods. For AL 3, we applied a new code to analyse its colour-magnitude diagram. Synthetic spectra were computed and compared to observed spectra for the three clusters. Results. We present a detailed identification of lines in the spectral region centred at 15 555 Å, covering the wavelength range 15 525–15 590 Å. C, N, and O abundances are tentatively derived for the sample stars.

scholarly journals Hubble Space Telescope imaging of globular cluster candidates in low surface brightness dwarf galaxies

2005 ◽  
Vol 442 (1) ◽  
pp. 85-95 ◽  
Author(s):  
M. E. Sharina ◽  
T. H. Puzia ◽  
D. I. Makarov
Keyword(s):  
Globular Cluster ◽  
Surface Brightness ◽  
Dwarf Galaxies ◽  
Hubble Space Telescope ◽  
Space Telescope ◽  
Low Surface Brightness
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