X-Ray Light Curve Modelling of SS 433

Context.Close binary systems provide an excellent tool for determining stellar parameters such as radii and masses with a high degree of precision. Due to the high rotational velocities, most of these systems exhibit strong signs of magnetic activity, postulated to be the underlying reason for radius inflation in many of the components. Aims.We extend the sample of low-mass binary systems with well-known X-ray properties. Methods.We analyze data from a singular XMM-Newton pointing of the close, low-mass eclipsing binary system BX Tri. The UV light curve was modeled with the eclipsing binary modeling tool PHOEBE and data acquired with the EPIC cameras was analyzed to search for hints of orbital modulation. Results.We find clear evidence of orbital modulation in the UV light curve and show that PHOEBE is fully capable of modeling data within this wavelength range. Comparison to a theoretical flux prediction based on PHOENIX models shows that the majority of UV emission is of photospheric origin. While the X-ray light curve does exhibit strong variations, the signal-to-noise ratio of the observation is insufficient for a clear detection of signs of orbital modulation. There is evidence of a Neupert-like correlation between UV and X-ray data.

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Urca nuclide production in Type-I X-ray bursts and implications for nuclear physics studies

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3414 ◽

2020 ◽

Vol 500 (3) ◽

pp. 2958-2968

Author(s):

Grant Merz ◽

Zach Meisel

Keyword(s):

Light Curve ◽

Nuclear Reaction ◽

Nuclear Physics ◽

Thermal Structure ◽

Reaction Rates ◽

High Mass ◽

Type I ◽

Model Calculations ◽

X Ray ◽

Lower Temperature

ABSTRACT The thermal structure of accreting neutron stars is affected by the presence of urca nuclei in the neutron star crust. Nuclear isobars harbouring urca nuclides can be produced in the ashes of Type I X-ray bursts, but the details of their production have not yet been explored. Using the code MESA, we investigate urca nuclide production in a one-dimensional model of Type I X-ray bursts using astrophysical conditions thought to resemble the source GS 1826-24. We find that high-mass (A ≥ 55) urca nuclei are primarily produced late in the X-ray burst, during hydrogen-burning freeze-out that corresponds to the tail of the burst light curve. The ∼0.4–0.6 GK temperature relevant for the nucleosynthesis of these urca nuclides is much lower than the ∼1 GK temperature most relevant for X-ray burst light curve impacts by nuclear reaction rates involving high-mass nuclides. The latter temperature is often assumed for nuclear physics studies. Therefore, our findings alter the excitation energy range of interest in compound nuclei for nuclear physics studies of urca nuclide production. We demonstrate that for some cases this will need to be considered in planning for nuclear physics experiments. Additionally, we show that the lower temperature range for urca nuclide production explains why variations of some nuclear reaction rates in model calculations impacts the burst light curve but not local features of the burst ashes.

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Coupled Radio and X‐Ray Emission and Evidence for Discrete Ejecta in the Jets of SS 433

The Astrophysical Journal ◽

10.1086/589144 ◽

2008 ◽

Vol 682 (2) ◽

pp. 1141-1151 ◽

Cited By ~ 14

Author(s):

J. C. A. Miller‐Jones ◽

S. Migliari ◽

R. P. Fender ◽

T. W. J. Thompson ◽

M. van der Klis ◽

...

Keyword(s):

X Ray ◽

Ss 433

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Iron Emission Lines from Extended X-ray Jets in SS 433: Reheating of Atomic Nuclei

Science ◽

10.1126/science.1073660 ◽

2002 ◽

Vol 297 (5587) ◽

pp. 1673-1676 ◽

Cited By ~ 86

Author(s):

S. Migliari

Keyword(s):

Emission Lines ◽

X Ray ◽

Ss 433 ◽

Atomic Nuclei

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Hydrodynamic Models of Solar and Stellar Flares

International Astronomical Union Colloquium ◽

10.1017/s0252921100031948 ◽

1989 ◽

Vol 104 (1) ◽

pp. 289-298

Author(s):

Giovanni Peres

Keyword(s):

High Resolution ◽

Light Curve ◽

Solar Flares ◽

Impulsive Phase ◽

Light Curves ◽

Physical Parameters ◽

The Sun ◽

Hydrodynamic Models ◽

X Ray ◽

Stellar Flares

AbstractThis paper discusses the hydrodynamic modeling of flaring plasma confined in magnetic loops and its objectives within the broader scope of flare physics. In particular, the Palermo-Harvard model is discussed along with its applications to the detailed fitting of X-ray light curves of solar flares and to the simulation of high-resolution Caxix spectra in the impulsive phase. These two approaches provide complementary constraints on the relevant features of solar flares. The extension to the stellar case, with the fitting of the light curve of an X-ray flare which occurred on Proxima Centauri, demonstrates the feasibility of using this kind of model for stars too. Although the stellar observations do not provide the wealth of details available for the Sun, and, therefore, constrain the model more loosely, there are strong motivations to pursue this line of research: the wider range of physical parameters in stellar flares and the possibility of studying further the solar-stellar connection.

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X-Ray Nova Flares

Symposium - International Astronomical Union ◽

10.1017/s0074180900010718 ◽

1975 ◽

Vol 67 ◽

pp. 501-508

Author(s):

P. R. Amnuel ◽

O. H. Guseinov

Keyword(s):

Light Curve ◽

Physical Nature ◽

Dwarf Star ◽

Optical Identification ◽

X Ray ◽

Spectral Class ◽

Maximum Value ◽

The Galaxy

In order to find out the physical nature of galactic X-ray sources, data on the variability of 24 sources during 1964–1971 have been investigated. The fluxes of 9 sources are found to be increasing to the maximum value (for several months) and then slowly decreasing (for 3 years). These 9 sources have been related by us to the class of X-ray Novae. The X-ray Nova synthetic light curve has been drawn from data of the fluxes of 9 discovered Novae. Assumptions have been made on the physical nature of the X-ray Novae. Between the flares the X-ray Novae may be weak X-ray sources with a luminosity of about 1034 erg s−1. During the flares the luminosity increases to about 1038 erg s−1. The number of X-ray sources in the Galaxy is about 103–104. The object of the optical identification may be a dwarf star of no earlier spectral class than F.

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