arXiv subjects

Norbert Hauck

Publications and source records attributed to Norbert Hauck.

6 recordsLinked to original sources

arXiv2026

A Be-shell star rotating at the critical limit and a partially stripped companion in a post-mass-transfer solution for the eclipsing binary V505 Mon

In this study of the eclipsing shell star binary HD 48914 (V505 Mon) existing photometric and radial velocity data have been completed by an unbiased determination of the surface temperature of the companion star and new data from the TESS mission. For the mean effective temperatures in our equatorial view, polar/equatorial radii and masses we get about 16000 K (dimmed), 4.27 / 6.37 Rsun and 7.40 Msun for the Be star, and about 14400 K, 6.19 / 7.17 Rsun and 2.03 Msun for the companion star (a contracting hot subdwarf precursor). Their calculated rotational equatorial velocities both are surprisingly high: 467 km/s for the Be star rotating at its centrifugal limit as well as 131 km/s for its former donor star companion. The Be star is surrounded by a large equatorial decretion disk having a radius of about 65 Rsun and fits into the main sequence of stellar models at a sub-solar metallicity of Z = 0.006.

astro-ph.SR↗

arXiv2026

A chemically peculiar Be-shell star in a sub-solar metallicity solution for the post-mass-transfer eclipsing binary V658 Car

V658 Car (HD 92406) is a newborn resp. rejuvenated shell star binary system at the age of only 1 Myr after the end of mass transfer. In this renewed study the peculiarities of the Be star are at first by-passed by the determination of the properties of the contracting hot subdwarf precursor, but finally resolved by combining photometric data and radial velocity results with existing stellar models. For the effective temperatures, radii and masses we get about 12900 K, 1.92/2.20 Rsun and 4.49 Msun for the Be star, and about 18400 K, 1.87 Rsun and 0.56 Msun for its companion star. The Be star has a rotational velocity of 336 km/s and is surrounded and dimmed in our view by a large and luminous equatorial decretion disk having a radius of ~ 42 Rsun. According to stellar models these results fit to a surprisingly low metallicity Z of 0.003 and a Teff ~ 5400 K higher than observational expectations for the Be star, which hence should belong to the chemically peculiar stars, in spite of its rapid rotation.

astro-ph.SR↗

arXiv2025

A very young and fast rotating shell star discovered in the eclipsing binary ZTF J200347.63+394429.8

A photometric study in combination with existing stellar models has revealed details of this eclipsing post-mass-transfer binary. The shell star has an equatorial/ polar radius of ~2.60/1.90 Rsun at an equatorial rotational velocity of ~430 km s-1, an effective mean temperature Teff of ~13300 K and a mass of ~3.42 Msun. This former accretor star is surrounded by a large decretion disk of ~47 Rsun. The secondary star is a helium white dwarf precursor with a radius of 0.98 Rsun, a Teff of ~17100 K and a mass of 0.29 Msun. The parameters of this former donor star indicate an age of the binary system of only ~1.8 Myr after the end of mass transfer. The results fit to a sub-solar metallicity of Z = 0.007.

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arXiv2023

A yellow giant, a peculiar A-type dwarf and an interstellar dust cloud unravel the eclipsing binary TYC 4481-358-1

A first solution for the eclipsing binary TYC 4481-358-1 has been found by combining the results of BVIc-photometry with known stellar models and stellar spectral energy distributions (SEDs). The binary shows total and annular eclipses in a circular 90-days orbit. Masses, radii and effective temperatures have been derived: about 3.01 Msun, 14.29 Rsun and 4950 K for the giant, and about 2.39 Msun, 2.39 Rsun and 9600 K for the dwarf. The peculiar dwarf is discolored and shows a Teff - passband dependence from 9000 K in the Ic to 9800 K in the B band. The giant is in its final stage of core helium burning. The interstellar extinction in our line of sight is considerable (Av about 1.44 mag at an elevated Rv of 3.58).

astro-ph.SR↗

arXiv2019

The first eclipsing B-shell + sdO binary discovered in HD 328058

An eclipsing binary with an orbital period of 62 days has been discovered in HD 328058 and studied by UBVIcHalpha photometry. Combining the results of light curve modelling with existing stellar models and known B3-shell spectral type of the primary star then allowed a reliable estimation of the mass, radius and effective temperature of both components: about 6.9 Msun, 5.2 Rsun and 17600 K for the primary star, and about 0.78 Msun, 1.20 Rsun and 56000 K for the hot subdwarf companion of type sdO. Obviously, this binary has been created by mass transfer of the envelope of the sdO progenitor to our primary star, now being a rapidly rotating shell star. Its spheroidal distortion and its decretion disk can be studied here unusually well.

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arXiv2018

Eclipsing binary V658 Carinae (HD 92406) containing a shell star and a hot low-mass star in the post-Algol stage

Further studies of the binary V658 Car (HD 92406) have now confirmed its unique main features, i.e. a shell star primary component being eclipsed by a hot low-mass star. Obviously, this binary is in its post-Algol evolutionary stage, and containing a rapidly rotating primary star and a contracting hot companion star. The analysis of old radial-velocity data indicating a primary star of lower mass has now resulted in amended parameters for the binary. According to stellar models the primary star should have a mass of 2.16 +/- 0.14 Msun and a radius of 1.64 +/- 0.04 Rsun for a Teff of 9700 +/- 500 K based on known spectral type A0p. For the secondary star 1.46 +/- 0.04 Rsun and 12750 +/- 700 K Teff have been derived and are fitting well to an existing evolutionary track for a contracting white dwarf precursor of 0.28 Msun. Our photometric results have confirmed the concave shape of the large decretion disk surrounding the primary star, as predicted by existing models.

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