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Browsing by Author "Edelmann, H."
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The B-type giant HD 271791 in the Galactic halo : Linking run-away stars to hyper-velocity stars
Heber, U.; Edelmann, H.; Napiwotzki, R.; Altmann, M.; Scholz, R.D. (2008-05-01)Context. Young, massive stars have been found in the distant Galactic halo. Dynamical ejection from the Galactic disc has been suggested as the origin of these "run-away stars". The so-called hyper-velocity stars have been ... -
Binaries discovered by the SPY project. I. HE 1047-0436: A subdwarf B white dwarf syste
Napiwotzki, R.; Edelmann, H.; Heber, U.; Karl, C.; Drechsel, H.; Pauli, E.M.; Christlieb, N. (2001-10)In the course of our search for double degenerate binaries as potential progenitors of type Ia supernovae with the UVES spectrograph at the ESO VLT (ESO SNIa Progenitor surveY { SPY) we discovered that the sdB star HE1047−0436 ... -
Binary sdB Stars with Massive Compact Companions
Geier, S.; Karl, C.; Edelmann, H.; Heber, U.; Napiwotzki, R. (Astronomical Society of the Pacific, 2008)The masses of compact objects like white dwarfs, neutron stars and black holes are fundamental to astrophysics, but very difficult to measure. We present the results of an analysis of subluminous B (sdB) stars in close ... -
Discovery of a helium-core white dwarf progenitor
Heber, U.; Edelmann, H.; Lisker, T.; Napiwotzki, R. (2003-12) -
HE 0437-5439: an unbound hypervelocity main-sequence B-type star
Edelmann, H.; Napiwotzki, R.; Heber, U.; Christlieb, N.; Reimers, D. (2005) -
Hot subdwarf stars in close-up view. I. Rotational properties of subdwarf B stars in close binary systems and nature of their unseen companions
Geier, S.; Heber, U.; Podsiadlowski, P.; Edelmann, H.; Napiwotzki, R.; Kupfer, T.; Muller, S. (2010)The origin of hot subdwarf B stars (sdBs) is still unclear. About half of the known sdBs are in close binary systems for which common envelope ejection is the most likely formation channel. Little is known about this dynamic ... -
Hypervelocity Stars: Young and Heavy or Old and Light?
Heber, U.; Hirsch, H.; Edelmann, H.; Napiwotzki, R.; O'Toole, S.; Brown, W.; Altmann, M. (Astronomical Society of the Pacific, 2008)The first three hyper-velocity stars (HVS) unbound to the Galaxy were serendipitously discovered in 2005. The only suggested origin of hyper-velocity stars is the Galactic Centre as it hosts a super-massive black hole ... -
LMC origin of the hyper-velocity star HE 0437-5439: Beyond the supermassive black hole paradigm
Przybilla, N.; Nieva, M.A.; Heber, U.; Firnstein, M.; Butler, K.; Napiwotzki, R.; Edelmann, H. (2008) -
Metal abundances of sdB stars
Edelmann, H.; Heber, U.; Napiwotzki, R. (2001) -
Spectral analysis of hot subluminous stars
Heber, U.; Edelmann, H.; Lemke, M.; Napiwotzki, R.; Engels, D. (Astronomical Society of the Pacific, 1999)Optical spectra of 40 sdOB stars drawn from the Palomar Green and the Hamburg-Schmidt surveys are presented (including three EC 14026 stars). Eight of which are spectroscopic binaries. -
Spectral Analysis of sdB Stars from the Hamburg ESO Survey
Edelmann, H.; Heber, U.; Napiwotzki, R.; Lemke, M.; Christlieb, N. (2001) -
Spectral analysis of sdB Stars from the Hamburg ESO Survey
Edelmann, H.; Heber, U.; Napiwotzki, R.; Lemke, M.; Christlieb, N. (Astronomical Society of the Pacific, 2001)We aim at the compilation of a statistically complete sample of sdB stars in the southern hemisphere. Candidates are selected from the database of digitized spectra of the Hamburg/ESO objective prism survey. First simulations ... -
Spectral analysis of sdB Stars from the Hamburg Quasar Survey
Edelmann, H.; Heber, U.; Hagen, H.J.; Dreizler, S.; Napiwotzki, R.; Engels, D.; Lemke, M. (2003-03) -
Spectral analysis of the binary sdB star Feige 36
Edelmann, H.; Heber, U.; Napiwotzki, R.; Reid, I.N.; Saffer, R. (Astronomical Society of the Pacific, 1999)The sdB stars Feige 36 is a short-period, single-lined spectroscopic binary. Aymospheric parameters and abundances are determined from high-resolution Keck spectra. Feige 36 lies near the zero-age extreme Horizontal Branch ... -
Spectral Monitoring of HS 0209+0832 a DAB White Dwarf in the DB Gap
Edelmann, H.; Heber, U.; Napiwotzki, R. (Astronomical Society of the Pacific, 2001)We report results of a spectral monitoring campagne of the DAB white dwarf HS 0209+0832, for which helium line profile variations were reported earlier (Heber et al. 1997). This finding is confirmed by our discovery of a ... -
Spectroscopic Analysis of Subluminous B Stars in Binaries with Compact Companions
Geier, S.; Karl, C.; Edelmann, H.; Heber, U.; Napiwotzki, R. (Astronomical Society of the Pacific, 2007)The masses of compact objects like white dwarfs, neutron stars and black holes are fundamental to astrophysics, but very difficult to measure. We present the results of an analysis of subluminous B (sdB) stars in close ...