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相关论文: The Formation of Cataclysmic Variables with Brown …

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We find that the ROSAT source 1RXS J105010.3-140431 is a cataclysmic variable with orbital period of 88.6 minutes and a spectrum closely resembling WZ Sge. In particular, emission lines are flanked by Stark-broadened absorption wings…

天体物理学 · 物理学 2009-11-06 R. E. Mennickent , M. Diaz , W. Skidmore , C. Sterken

In order to determine the spatial distribution, Galactic model parameters and luminosity function of cataclysmic variables (CVs), a $J$-band magnitude limited sample of 263 CVs has been established using a newly constructed…

星系天体物理 · 物理学 2015-06-22 A. Ozdonmez , T. Ak , S. Bilir

The formation of brown dwarfs (BDs) poses a key challenge to star formation theory. The observed dearth of nearby ($\leq 5$ AU) brown dwarf companions to solar-mass stars, known as the brown dwarf desert, as well as the tendency for…

太阳与恒星天体物理 · 物理学 2015-03-20 Peter H. Jumper , Robert T. Fisher

We report the results of a statistical study of cyclical period changes in cataclysmic variables (CVs). Assuming the third-body hypothesis as the cause of period changes, we estimate the third-body mass, $m_3$, and its separation from the…

太阳与恒星天体物理 · 物理学 2024-08-16 Leandro Souza , Raymundo Baptista

We suggest that a high proportion of brown dwarfs are formed by gravitational fragmentation of massive extended discs around Sun-like stars. Such discs should arise frequently, but should be observed infrequently, precisely because they…

天体物理学 · 物理学 2009-11-13 Dimitris Stamatellos , Anthony P. Whitworth

A substantial fraction of Cataclysmic Variables (CVs) reveals non-solar abundances. A comprehensive list of CVs which includes those that have been examined for these abundances is given. Three possible sources of these non-solar abundances…

太阳与恒星天体物理 · 物理学 2021-06-23 Warren M. Sparks , Edward M. Sion

The average white dwarf (WD) masses in cataclysmic variables (CVs) have been measured to significantly exceed those of single WDs, which is the opposite of what is theoretically expected. We present the results of binary population…

太阳与恒星天体物理 · 物理学 2015-10-28 Matthias R. Schreiber , Monica Zorotovic , Thomas P. G. Wijnen

Strong selection effects are present in observational samples of cataclysmic variables (CVs), complicating comparisons to theoretical predictions. The selection criteria used to define most CV samples discriminate heavily against the…

天体物理学 · 物理学 2009-11-13 Magaretha L. Pretorius , Christian Knigge

The evolution of Cataclysmic Variables (CVs) is driven by period-changes ($\dot{P}$), for which the long-venerable consensus is the Magnetic Braking Model (MBM). The MBM has its only distinctive assumption being a power-law `recipe'…

太阳与恒星天体物理 · 物理学 2024-04-22 Bradley E. Schaefer

We have been investigating populations of cataclysmic variables (CVs) in a set of more than 300 globular cluster (GC) models evolved with the MOCCA code. One of the main questions we have intended to answer is whether most CVs in GCs are…

星系天体物理 · 物理学 2020-03-18 Diogo Belloni , Mirek Giersz , Liliana E. Rivera Sandoval , Abbas Askar , Pawel Ciecielag

We resume the discussion about irradiation-driven mass transfer cycles in semi- detached compact binary systems. The analytical model that describes the onset of these cycles, which occur on a thermal timescale of the donor star, is…

天体物理学 · 物理学 2009-11-10 A. Büning , H. Ritter

The formation mechanism of Brown Dwarfs (BDs), whether akin to stars or ejected planetary-mass objects, remains debated. We present the first 3D radiation-MHD simulations of magnetized, turbulent, gravitationally unstable low-mass cores…

太阳与恒星天体物理 · 物理学 2025-09-17 Adnan Ali Ahmad , Benoît Commerçon , Gilles Chabrier , Antonin Borderies

We show that the secondaries in short-period cataclysmic variables with orbital periods $P < 3$ hr are close to the solar-abundance main sequence defined by single field stars. In cataclysmic variables with $P > 3$ hr, the earliest spectral…

天体物理学 · 物理学 2007-05-23 K. Beuermann , I. Baraffe , U. Kolb , M. Weichhold

We derive metallicities for 41 cataclysmic variables (CVs) from near-infrared spectroscopy. We use synthetic spectra that cover the 0.8 $\mu$m $\leq \lambda \leq$ 2.5 $\mu$m bandpass to ascertain the value of [Fe/H] for CVs with K-type…

太阳与恒星天体物理 · 物理学 2016-12-14 Thomas E. Harrison

We focus on short--period eclipsing binaries that belong to a class of Cataclysmic Variables (CVs). They are known as polars and intermediate polars, closely resembling their prototype AM Herculis. These binaries consist of a red dwarf and…

地球与行星天体物理 · 物理学 2014-03-20 Aga Słowikowska , Krzysztof Goździewski , Ilham Nasiroglu , Gottfried Kanbach , Arne Rau , Krzysztof Krzeszowski

We present HST spectroscopy for 45 cataclysmic variables (CVs), observed with HST/COS and HST/STIS. For 36 CVs, the white dwarf is recognisable through its broad Ly$\alpha$ absorption profile and we measure the white dwarf effective…

Circumbinary planets and brown dwarfs form in complex gravitational environments, offering insights into formation, orbital stability, and habitability prospects. However, they remain underrepresented, with only 60 confirmed or candidate…

地球与行星天体物理 · 物理学 2025-09-26 Ekrem Murat Esmer , Tansu Daylan

Current evolutionary models imply that most Cataclysmic Variables (CVs) have P_orb<2 hours and are Dwarf Nova (DN) systems that are quiescent most of the time. Observations of nearby quiescent DN find that the UV spectrum is dominated by…

天体物理学 · 物理学 2009-11-07 Dean M. Townsley , Lars Bildsten

The formation of brown dwarfs (BDs) due to the fragmentation of proto-stellar disks undergoing pairwise encounters was investigated. High resolution allowed the use of realistic initial disk models where both the vertical structure and the…

太阳与恒星天体物理 · 物理学 2015-05-14 Sijing Shen , James Wadsley , Tristen Hayfield , Nicholas Ellens

The 2dF QSO survey is a spectroscopic survey of 48,000 point-sources selected by colour with magnitudes in the range 18.35 < B < 20.95. Amongst QSOs, white dwarfs, narrow-line galaxies and other objects are some cataclysmic variables (CVs).…