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Related papers: The Clusters AgeS Experiment (CASE). III. Analysis…

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Evidence is emerging that the luminous X-ray sources in the cores of globular clusters may often consist of, or perhaps even as a class be dominated by, ultracompact (P < 1 hr) binary stars. To the two such systems already known, in NGC…

Astrophysics · Physics 2009-10-31 Eric W. Deutsch , Bruce Margon , Scott F. Anderson

We report results of the Chandra deep imaging observation of the closest post-core collapse globular cluster, NGC 6397. Some 25 sources are detected within 2 arcmin of the cluster center of which about 20 are likely cluster members with L_x…

Astrophysics · Physics 2009-11-07 J. E. Grindlay , C. O. Heinke , P. D. Edmonds , S. S. Murray , A. M. Cool

We present a study based on more than 2500 uvby-measurements collected on HD 172189, a new eclipsing binary system with a Delta Sct-type pulsating component that belongs to the open cluster IC 4756. The great interest of this object lies in…

Astrophysics · Physics 2009-11-11 S. Martin-Ruiz , P. J. Amado , J. C. suarez , A. Moya , A. Arellano Ferro , I. Ribas , E. Poretti

In this paper we have examined the internal dynamics of the globular cluster NGC 362. A V band surface brightness profile (SBP) was constructed from CCD images, and, after it was determined that the cluster is not post core-collapse, fit…

Astrophysics · Physics 2009-10-22 P. Fischer , D. L. Welch , M. Mateo , P. Côté

We present light curve analyses of two newly identified detached eclipsing binaries, HD 96609 and HD 303734, in the region of the richly populated open cluster NGC 3532. HD 96609 is composed of two main sequence stars (B9-A0V + A2V) with…

Solar and Stellar Astrophysics · Physics 2021-11-17 Orkun Özdarcan

SuWt2 is a planetary nebula (PN) consisting of a bright ionized thin ring seen nearly edge-on. It has a bright (V=12) central star, too cool to ionize the PN, which we discovered to be an eclipsing binary. A spectrum from IUE did not reveal…

Solar and Stellar Astrophysics · Physics 2015-05-19 K. Exter , Howard E. Bond , Keivan G. Stassun , B. Smalley , P. F. L. Maxted , D. L. Pollacco

Galactic star clusters are known to harbour a significant amount of binary stars, yet their role in the dynamical evolution of the cluster as a whole is not comprehensively understood. We investigated the influence of binary stars on the…

Astrophysics of Galaxies · Physics 2022-05-11 L. Yalyalieva , G. Carraro , E. Glushkova , U. Munari , P. Ochner

As a by-product of high-precision, ultra-deep stellar photometry in the Galactic globular cluster NGC 6397 with the Hubble Space Telescope, we are able to measure a large population of background galaxies whose images are nearly point-like.…

NGC 6397 is the second closest globular star cluster to the Sun. Using 5 days of time on the Hubble Space Telescope, we have constructed the deepest ever color-magnitude diagram for this cluster. We see a clear truncation in each of its two…

Among the competing evolution theories for subdwarf-B (sdB) stars is the binary evolution scenario. EC~20117-4014 (=V4640~Sgr) is a spectroscopic binary system consisting of a pulsating sdB star and a late F main-sequence companion…

Solar and Stellar Astrophysics · Physics 2018-06-13 T. Otani , T. Oswalt , A. E. Lynas-Gray , D. Kilkenny , K. Koen , M. Amaral , R. Jordan

We present analyses of improved photometric and spectroscopic observations for two detached eclipsing binaries at the turnoff of the open cluster NGC 752: the 1.01 day binary DS And and the 15.53 d BD $+$37 410. For DS And, we find $M_1 =…

In a systematic search for eclipsing white dwarfs using Zwicky transient facility (ZTF) data, we found seven eclipsing double white dwarfs with orbital periods ranging from 45 minutes to 3 hours. We collected high-speed light curves,…

We present the analysis of an eccentric, partially eclipsing long-period ($P=19.23$ d) binary system KIC 9777062 that contains main sequence stars near the turnoff of the intermediate age open cluster NGC 6811. The primary is a metal-lined…

We present VI-band photometry for stars in the metal-rich globular cluster NGC 6496. Our time-series data were cadenced to search for long period variables (LPVs) over a span of nearly two years, and our variability search yielded the…

Aims: The analysis of combined photometry and spectroscopy of eccentric eclipsing binary systems facilitates the derivation of precise values for the parameters of the component stars and their orbits, thereby providing stringent tests of…

Solar and Stellar Astrophysics · Physics 2023-02-10 P. Zasche , D. Sürgit , A. Erdem , C. A. Engelbrecht , F. Marang

BVR light curves and radial velocities for the double-lined eclipsing binary V1135\,Her were obtained. The brighter component of V1135\,Her is a Cepheid variable with a pulsation period of 4.22433$\pm$0.00026 days. The orbital period of the…

Solar and Stellar Astrophysics · Physics 2013-04-23 E. Sipahi , C. Ibanoglu , O. Cakirli , H. A. Dal , S. Evren

With 16-month Kepler data, 14 long-period (40 d - 265 d) eclipsing binaries on highly eccentric orbits (minimum e between 0.5 and 0.85) are recognized from their closely separated primary and secondary eclipses (\Delta t_I,II = 3 d - 10 d).…

Solar and Stellar Astrophysics · Physics 2012-12-27 Subo Dong , Boaz Katz , Aristotle Socrates

As part of our study of the old (~2.5 Gyr) open cluster NGC 6819 in the Kepler field, we present photometric (Kepler and ground-based BVRcIc) and spectroscopic observations of the detached eclipsing binary WOCS 24009 (Auner 665; KIC…

The study of detached eclipsing binaries in open clusters can provide stringent tests of theoretical stellar evolutionary models, which must simultaneously fit the masses, radii, and luminosities of the eclipsing stars and the radiative…

Astrophysics · Physics 2007-05-23 John Southworth , J V Clausen