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Based on high-resolution optical spectroscopy in the blue and the near infra-red spectral range, we derived velocity images (Doppler tomograms) of the mass-donating secondary star and the accretion stream of the long-period eclipsing polar…

Astrophysics · Physics 2009-11-06 A. Staude , A. D. Schwope , R. Schwarz

We present orbital-phase resolved I and K-band spectroscopy of Cygnus X-3. All spectra show emission lines characteristic of Wolf-Rayet stars of the WN subclass. On time scales longer than about one day, the line strengths show large…

Astrophysics · Physics 2007-05-23 M. H. van Kerkwijk , T. R. Geballe , D. L. King , M. van der Klis , J. van Paradijs

During the next closest approach of the orbiting star S2/S0-2 to the Galactic supermassive black hole (SMBH), it is estimated that RV uncertainties of ~ 10 km/s allow us to detect post-Newtonian effects throughout 2018. To evaluate an…

We present high precision radial velocities (RVs) of double-lined spectroscopic binary stars HD78418, HD123999, HD160922, HD200077 and HD210027. They were obtained based on the high resolution echelle spectra collected with the Keck…

Solar and Stellar Astrophysics · Physics 2014-11-20 M. Konacki , M. Muterspaugh , S. Kulkarni , K. Helminiak

We have performed the near-infrared photometric monitoring observations of two TeV gamma-ray binaries with O-stars (LS 5039 and 1FGL J1018.6-5856), using IRSF/SIRIUS at SAAO, in order to study the stellar parameters and their perturbations…

High Energy Astrophysical Phenomena · Physics 2023-04-26 Yuki Moritani , Akiko Kawachi , Atsuo T. Okazaki , Sho Chimasu , Hiromi Yoshida

Radial-velocity measurements and sine-curve fits to the orbital velocity variations are presented for the seventh set of ten close binary systems: V410 Aur, V523 Cas, QW Gem, V921 Her, V2357 Oph, V1130 Tau, HN UMa, HX UMa, HD 93917, NSV…

Context. WR104 is an emblematic dusty Wolf-Rayet star and the prototypical member of a subgroup hosting spirals that are mainly observable with high-angular resolution techniques. Previous aperture masking observations showed that WR104 is…

Wolf-Rayet (WR) stars are helium-burning, evolved massive stars which have had most of their hydrogen-rich outer layers removed either through stellar winds and/or binary stripping. Here we report on LMC173-1, a WN3+O binary located in the…

Classical Wolf-Rayet stars are the descendants of massive OB stars that have lost their hydrogen envelopes and are burning helium in their cores prior to exploding as type Ib/c supernovae. The mechanisms for losing their hydrogen envelopes…

We discuss the spin-orbit orientation of the Fomalhaut planetary system composed of a central A4V star, a debris disk, and a recently discovered planetary companion. We use spectrally resolved, near-IR long baseline interferometry to obtain…

Solar and Stellar Astrophysics · Physics 2015-05-13 Jean-Baptiste Le Bouquin , Olivier Absil , Myriam Benisty , Fabrizio Massi , Antoine Merand , Stan Stefl

Optical-infrared interferometry can provide direct geometrical measurements of the radii of Cepheids and/or reveal unknown binary companions of these stars. Such information is of great importance for a proper calibration of…

Solar and Stellar Astrophysics · Physics 2015-06-12 G. Li Causi , S. Antoniucci , G. Bono , S. Pedicelli , D. Lorenzetti , T. Giannini , B. Nisini

PODIUM is a compact spacecraft navigation unit, currently being designed to provide interplanetary missions with autonomous position and velocity estimations. The unit will make use of Pulsar X-ray observations to measure the distance and…

In this paper we present a spectroscopic study of six double-lined binaries, five of which were recently discovered in a high-resolution spectroscopic survey of optical counterparts of stellar X-ray sources. Thanks to high-resolution…

Solar and Stellar Astrophysics · Physics 2022-07-08 A. Frasca , G. Catanzaro , I. Busà , P. Guillout , J. Alonso-Santiago , C. Ferrara , M. Giarrusso , M. Munari , F. Leone

$Aims.$ We present a database of 43,340 atmospheric models ($\sim$80,000 models at the conclusion of the project) for stars with stellar masses between 9 and 120 $M_{\odot}$, covering the region of the OB main-sequence and Wolf-Rayet (W-R)…

Solar and Stellar Astrophysics · Physics 2020-11-18 J. Zsargo , C. R. Fierro-Santillan , J. Klapp , A. Arrieta , L. Arias , J. M. Valencia , L. Di G. Sigalotti , M. Hareter , R. E. Puebla

We present an analysis of long-term X-ray and optical observations of the Wolf-Rayet binary WR 25. Using archival data from observations with the XMM-Newton and the Swift observatories spanning over ~10 yr, we show that WR 25 is a periodic…

Solar and Stellar Astrophysics · Physics 2014-05-29 J. C. Pandey , S. B. Pandey , Subhajeet Karmakar

A newly developed 3-D Monte Carlo model is used, in conjunction with a multi-line non-LTE radiative transfer model, to determine the mass-loss rate of the Wolf-Rayet (W-R) star in the massive binary \object{V444 Cyg} (WN5+O6). This…

Astrophysics · Physics 2016-08-30 R. Kurosawa , D. J. Hillier , J. M. Pittard

We discovered that the Wolf-Rayet (WR)+OB star binary, WR 104, renowned for its associated "dusty pinwheel nebula" recently spatially resolved with infrared interferometry, exhibits strong quasi-periodic optical variations with a full…

Astrophysics · Physics 2015-06-24 T. Kato , K. Haseda , H. Yamaoka , K. Takamizawa

We present the discovery of OB type absorption lines superimposed to the emission line spectrum, and the first double-lined orbital elements for the massive Wolf-Rayet binary HDE 318016 (=WR 98), a spectroscopic binary in a circular orbit…

Astrophysics · Physics 2007-05-23 Roberto C. Gamen , Virpi S. Niemela

The non-thermal 3.6 cm radio continuum emission from the young stars S1 and DoAr21 in the core of Ophiuchus, has been observed with the Very Long Baseline Array (VLBA) at 6 and 7 epochs, respectively, between June 2005 and August 2006. The…

Astrophysics · Physics 2008-03-21 Laurent Loinard , Rosa M. Torres , Amy Mioduszewski , Luis F. Rodriguez

We report low resolution near infrared spectroscopic observations of the eruptive star FU Orionis using the Integral Field Spectrograph Project 1640 installed at the Palomar Hale telescope. This work focuses on elucidating the nature of the…