Beuermann, Klaus Peter

[["dc.bibliographiccitation.firstpage","671"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Astronomy and Astrophysics"],["dc.bibliographiccitation.lastpage","681"],["dc.bibliographiccitation.volume","451"],["dc.contributor.author","Euchner, F."],["dc.contributor.author","Jordan, S."],["dc.contributor.author","Beuermann, Klaus"],["dc.contributor.author","Reinsch, K."],["dc.contributor.author","Gansicke, B. T."],["dc.date.accessioned","2018-11-07T09:50:53Z"],["dc.date.available","2018-11-07T09:50:53Z"],["dc.date.issued","2006"],["dc.description.abstract","Aims. We analyse the magnetic field geometry of the magnetic DA white dwarf PG1015+014 with our Zeeman tomography method. Methods. This study is based on rotation-phase resolved optical flux and circular polarization spectra of PG1015+014 obtained with FORS1 at the ESO VLT. Our tomographic code makes use of an extensive database of pre-computed Zeeman spectra. The general approach has been described in Papers I and II of this series. Results. The surface field strength distributions for all rotational phases of PG1015+014 are characterised by a strong peak at 70 MG. A separate peak at 80MG is seen for about one third of the rotation cycle. Significant contributions to the Zeeman features arise from regions with field strengths between 50 and 90 MG. We obtain equally good simultaneous fits to the observations, collected in five phase bins, for two different field parametrizations: (i) a superposition of individually tilted and off-centred zonal multipole components; and (ii) a truncated multipole expansion up to degree l = 4 including all zonal and tesseral components. The magnetic fields generated by both parametrizations exhibit a similar global structure of the absolute surface field values, but differ considerably in the topology of the field lines. An effective photospheric temperature of T-eff = 10 000 +/- 1000 K was found. Conclusions. Remaining discrepancies between the observations and our best-fit models suggest that additional small-scale structure of the magnetic field exists which our field models are unable to cover due to the restricted number of free parameters."],["dc.identifier.doi","10.1051/0004-6361:20064840"],["dc.identifier.fs","45028"],["dc.identifier.isi","237272100027"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/9385"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/35801"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Edp Sciences S A"],["dc.relation.issn","1432-0746"],["dc.relation.orgunit","Fakultät für Physik"],["dc.title","Zeeman tomography of magnetic white dwarfs - III. The 70-80 Megagauss magnetic field of PG1015+014"],["dc.title.original","9385"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","211"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Astronomy and Astrophysics"],["dc.bibliographiccitation.lastpage","221"],["dc.bibliographiccitation.volume","373"],["dc.contributor.author","Fischer, A."],["dc.contributor.author","Beuermann, Klaus"],["dc.date.accessioned","2018-11-07T08:53:40Z"],["dc.date.available","2018-11-07T08:53:40Z"],["dc.date.issued","2001"],["dc.description.abstract","We have solved the one-dimensional stationary two-fluid hydrodynamic equations for post-shock flows on accreting magnetic white dwarfs simultaneous with the fully frequency and angle-dependent radiative transfer for cyclotron radiation and bremsstrahlung. Magnetic field strengths B = 10 to 100 MG are considered. At given B, this theory relates the properties of the emission region to a single physical parameter, the mass ow density (or accretion rate per unit area) (m) over dot. We present the normalized temperature profiles and fit formulae for the peak electron temperature, the geometrical shock height, and the column density of the post-shock ow. The results apply to pillbox-shaped emission regions. With a first-order temperature correction they can also be used for narrower columns provided they are not too tall."],["dc.identifier.doi","10.1051/0004-6361:20010600"],["dc.identifier.isi","000169967200023"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/9707"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/22476"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","0004-6361"],["dc.relation.orgunit","Fakultät für Physik"],["dc.title","Accretion physics of AM Herculis binaries - I. Results from one-dimensional stationary radiation hydrodynamics"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","A8"],["dc.bibliographiccitation.journal","Astronomy and Astrophysics"],["dc.bibliographiccitation.volume","540"],["dc.contributor.author","Beuermann, Klaus"],["dc.contributor.author","Breitenstein, P."],["dc.contributor.author","Debski, B."],["dc.contributor.author","Diese, J."],["dc.contributor.author","Dubovsky, P. A."],["dc.contributor.author","Dreizler, Stefan"],["dc.contributor.author","Hessman, Frederic V."],["dc.contributor.author","Hornoch, K."],["dc.contributor.author","Husser, T.-O."],["dc.contributor.author","Pojmanski, G."],["dc.contributor.author","Wolf, M."],["dc.contributor.author","Wozniak, P. R."],["dc.contributor.author","Zasche, P."],["dc.contributor.author","Denk, B."],["dc.contributor.author","Langer, M."],["dc.contributor.author","Wagner, C."],["dc.contributor.author","Wahrenberg, D."],["dc.contributor.author","Bollmann, T."],["dc.contributor.author","Habermann, F. N."],["dc.contributor.author","Haustovich, N."],["dc.contributor.author","Lauser, M."],["dc.contributor.author","Liebing, F."],["dc.contributor.author","Niederstadt, F."],["dc.date.accessioned","2018-11-07T09:11:26Z"],["dc.date.available","2018-11-07T09:11:26Z"],["dc.date.issued","2012"],["dc.description.abstract","We report new mid-eclipse times of the two close binaries NSVS14256825 and HS0705+6700, harboring an sdB primary and a low-mass main-sequence secondary. Both objects display clear variations in their measured orbital period, which can be explained by the action of a third object orbiting the binary. If this interpretation is correct, the third object in NSVS14256825 is a giant planet with a mass of roughly 12 M-Jup. For HS0705+6700, we provide evidence that strengthens the case for the suggested periodic nature of the eclipse time variation and reduces the uncertainties in the parameters of the brown dwarf implied by that model. The derived period is 8.4 yr and the mass is 31 M-Jup, if the orbit is coplanar with the binary. This research is part of the PlanetFinders project, an ongoing collaboration between professional astronomers and student groups at high schools."],["dc.identifier.doi","10.1051/0004-6361/201118105"],["dc.identifier.fs","596639"],["dc.identifier.isi","000303315400022"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/9592"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/26723"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Edp Sciences S A"],["dc.relation.issn","0004-6361"],["dc.relation.orgunit","Fakultät für Physik"],["dc.title","The quest for companions to post-common envelope binaries II. NSVS14256825 and HS0705+6700"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","651"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Astronomy and Astrophysics"],["dc.bibliographiccitation.lastpage","660"],["dc.bibliographiccitation.volume","442"],["dc.contributor.author","Euchner, F."],["dc.contributor.author","Reinsch, K."],["dc.contributor.author","Jordan, S."],["dc.contributor.author","Beuermann, Klaus"],["dc.contributor.author","Gansicke, B. T."],["dc.date.accessioned","2018-11-07T10:54:29Z"],["dc.date.available","2018-11-07T10:54:29Z"],["dc.date.issued","2005"],["dc.description.abstract","We report time-resolved optical flux and circular polarization spectroscopy of the magnetic DA white dwarf HE 1045- 0908 obtained with FORS1 at the ESO VLT. Considering published results, we estimate a likely rotational period of P-rot similar or equal to 2.7 h, but cannot exclude values as high as about 9 h. Our detailed Zeeman tomographic analysis reveals a field structure which is dominated by a quadrupole and contains additional dipole and octupole contributions, and which does not depend strongly on the assumed value of the period. A good fit to the Zeeman flux and polarization spectra is obtained if all field components are centred and inclinations of their magnetic axes with respect to each other are allowed for. The fit can be slightly improved if an offset from the centre of the star is included. The prevailing surface field strength is 16 MG, but values between 10 and similar to 75 MG do occur. We derive an effective photospheric temperature of HE 1045- 0908 of T-eff = 10 000 +/- 1000 K. The tomographic code makes use of an extensive database of pre-computed Zeeman spectra ( Paper I)."],["dc.identifier.doi","10.1051/0004-6361:20053038"],["dc.identifier.isi","232404400032"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/9389"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/49572"],["dc.notes.intern","In goescholar not merged with http://resolver.sub.uni-goettingen.de/purl?gs-1/9853 but duplicate"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Edp Sciences S A"],["dc.relation.issn","1432-0746"],["dc.rights","Goescholar"],["dc.rights.uri","https://goedoc.uni-goettingen.de/licenses"],["dc.title","Zeeman tomography of magnetic white dwarfs - II. The quadrupole-dominated magnetic field of HE 1045-0908"],["dc.title.original","9389"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","L60"],["dc.bibliographiccitation.journal","Astronomy and Astrophysics"],["dc.bibliographiccitation.volume","521"],["dc.contributor.author","Beuermann, Klaus"],["dc.contributor.author","Hessman, Frederic V."],["dc.contributor.author","Dreizler, Stefan"],["dc.contributor.author","Marsh, T. R."],["dc.contributor.author","Parsons, S. G."],["dc.contributor.author","Winget, D. E."],["dc.contributor.author","Miller, G. F."],["dc.contributor.author","Schreiber, M. R."],["dc.contributor.author","Kley, W."],["dc.contributor.author","Dhillon, V. S."],["dc.contributor.author","Littlefair, S. P."],["dc.contributor.author","Copperwheat, C. M."],["dc.contributor.author","Hermes, J. J."],["dc.date.accessioned","2018-11-07T08:38:15Z"],["dc.date.available","2018-11-07T08:38:15Z"],["dc.date.issued","2010"],["dc.description.abstract","Planets orbiting post-common envelope binaries provide fundamental information on planet formation and evolution. We searched for such planets in NN Ser ab, an eclipsing short-period binary that shows long-term eclipse time variations. Using published, reanalysed, and new mid-eclipse times of NN Ser ab obtained between 1988 and 2010, we find excellent agreement with the light-travel-time effect produced by two additional bodies superposed on the linear ephemeris of the binary. Our multi-parameter fits accompanied by N-body simulations yield a best fit for the objects NN Ser (ab)c and d locked in the 2:1 mean motion resonance, with orbital periods P-c similar or equal to 15.5 yrs and P-d similar or equal to 7.7 yrs, masses M-c sin i(c) similar or equal to 6.9 M-Jup and M-d sin i(d) similar or equal to 2.2 M-Jup, and eccentricities e(c) similar or equal to 0 and e(d) similar or equal to 0.20. A secondary chi(2) minimum corresponds to an alternative solution with a period ratio of 5:2. We estimate that the progenitor binary consisted of an A star with similar or equal to 2 M-circle dot and the present M dwarf secondary at an orbital separation of similar to 1.5 AU. The survival of two planets through the common-envelope phase that created the present white dwarf requires fine tuning between the gravitational force and the drag force experienced by them in the expanding envelope. The alternative is a second-generation origin in a circumbinary disk created at the end of this phase. In that case, the planets would be extremely young with ages not exceeding the cooling age of the white dwarf of 10(6) yrs."],["dc.identifier.doi","10.1051/0004-6361/201015472"],["dc.identifier.fs","581080"],["dc.identifier.isi","000284150900060"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/9671"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/18726"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Edp Sciences S A"],["dc.relation.issn","0004-6361"],["dc.relation.orgunit","Fakultät für Physik"],["dc.title","Two planets orbiting the recently formed post-common envelope binary NN Serpentis"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","470"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Astronomy and Astrophysics"],["dc.bibliographiccitation.lastpage","486"],["dc.bibliographiccitation.volume","367"],["dc.contributor.author","Grupe, D."],["dc.contributor.author","Thomas, H. C."],["dc.contributor.author","Beuermann, K."],["dc.date.accessioned","2019-07-09T11:54:48Z"],["dc.date.available","2019-07-09T11:54:48Z"],["dc.date.issued","2001"],["dc.description.abstract","We present ROSAT All-Sky Survey and ROSAT pointed observations (PSPC and HRI) of a complete sample of 113 bright soft X-ray AGN selected from the ROSAT Bright Source Catalog. We compare these observations in order to search for extreme cases of flux and spectral X-ray variability - X-ray transient AGN. Three definite transients and one transient candidate are found. The other sources show amplitude variations typically by factors of 2-3 on timescales of years. We found that the variability strength on timescales of days is a function of the steepness of the X-ray spectrum: steeper X-ray objects show stronger variability than flat X-ray spectrum sources. We also present new HRI measurements of our extreme X-ray transients IC 3599 and WPVS007. We discuss possible models to explain the X-ray transience and the variabilities observed in the non-transient sources."],["dc.identifier.doi","10.1051/0004-6361:20000429"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/9701"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/60728"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","final"],["dc.relation.issn","1432-0756"],["dc.relation.orgunit","Fakultät für Physik"],["dc.title","X-ray variability in a complete sample of Soft X-ray selected AGN"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","487"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Astronomy and Astrophysics"],["dc.bibliographiccitation.lastpage","490"],["dc.bibliographiccitation.volume","381"],["dc.contributor.author","Beuermann, Klaus"],["dc.contributor.author","Reinsch, K."],["dc.date.accessioned","2018-11-07T10:32:46Z"],["dc.date.available","2018-11-07T10:32:46Z"],["dc.date.issued","2002"],["dc.description.abstract","We have investigated the nature of the magnetic white dwarf LP 790-29 = LHS 2293 by polarimetric monitoring, searching for short-term variability. No periodicity was found and we can exclude rotation periods between 4 s and 1.5 hour with a high confidence. Maximum amplitudes of sinusoidal variations are DeltaR < 0.009 mag and Delta V-R < 0.7% for a mean value of the R-band circular polarization of V-R = -9.1 +/- 0.3%. Combined with earlier results by other authors, our observation suggests that LP 790-29 is, in fact, an extremely slowly rotating single white dwarf and not an unrecognized fast rotator and/or disguised cataclysmic variable."],["dc.identifier.doi","10.1051/0004-6361:20011478"],["dc.identifier.fs","19137"],["dc.identifier.isi","000173343100014"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/9720"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/44434"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Edp Sciences S A"],["dc.relation.issn","1432-0746"],["dc.relation.orgunit","Fakultät für Physik"],["dc.title","The high-field magnetic white dwarf LP790-29: Not a fast rotator"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","A133"],["dc.bibliographiccitation.journal","Astronomy and Astrophysics"],["dc.bibliographiccitation.volume","555"],["dc.contributor.author","Beuermann, Klaus"],["dc.contributor.author","Dreizler, Stefan"],["dc.contributor.author","Hessman, Frederic V."],["dc.date.accessioned","2018-11-07T09:22:45Z"],["dc.date.available","2018-11-07T09:22:45Z"],["dc.date.issued","2013"],["dc.description.abstract","We present 69 new mid-eclipse times of the young post-common envelope binary (PCEB) NN Ser, which was previously suggested to possess two circumbinary planets. We have interpreted the observed eclipse-time variations in terms of the light-travel time effect caused by two planets, exhaustively covering the multi-dimensional parameter space by fits in the two binary and ten orbital parameters. We supplemented the fits by stability calculations for all models with an acceptable chi(2). An island of secularly stable 2:1 resonant solutions exists, which coincides with the global chi(2) minimum. Our best-fit stable solution yields current orbital periods P-o = 15.47 yr and P-i = 7.65 yr and eccentricities e(o) = 0.14 and e(i) = 0.22 for the outer and inner planets, respectively. The companions qualify as giant planets, with masses of 7.0 M-Jup and 1.7 M-Jup for the case of orbits coplanar with that of the binary. The two-planet model that starts from the present system parameters has a lifetime greater than 10(8) yr, which significantly exceeds the age of NN Ser of 10(6) yr as a PCEB. The resonance is characterized by libration of the resonant variable Theta(1) and circulation of omega(i)-omega(o), the difference between the arguments of periapse of the two planets. No stable nonresonant solutions were found, and the possibility of a 5:2 resonance suggested previously by us is now excluded at the 99.3% confidence level."],["dc.description.sponsorship","Alfried Krupp von Bohlen und Halbach Foundation, Essen"],["dc.identifier.doi","10.1051/0004-6361/201220510"],["dc.identifier.isi","000322008600133"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/10577"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/29423"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Edp Sciences S A"],["dc.relation.issn","0004-6361"],["dc.relation.orgunit","Fakultät für Physik"],["dc.title","The quest for companions to post-common envelope binaries IV. The 2:1 mean-motion resonance of the planets orbiting NN Serpentis"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","A138"],["dc.bibliographiccitation.journal","Astronomy and Astrophysics"],["dc.bibliographiccitation.volume","543"],["dc.contributor.author","Beuermann, Klaus"],["dc.contributor.author","Dreizler, Stefan"],["dc.contributor.author","Hessman, Frederic V."],["dc.contributor.author","Deller, J."],["dc.date.accessioned","2018-11-07T09:08:27Z"],["dc.date.available","2018-11-07T09:08:27Z"],["dc.date.issued","2012"],["dc.description.abstract","We report new mid-eclipse times of the short-period sdB/dM binary HW Virginis, which differ substantially from the times predicted by a previous model. The proposed orbits of the two planets in that model are found to be unstable. We present a new secularly stable solution, which involves two companions orbiting HW Vir with periods of 12.7 yr and 55 +/- 15 yr. For orbits coplanar with the binary, the inner companion is a giant planet with mass M-3 sin i(3) similar or equal to 14 M-Jup and the outer one a brown dwarf or low-mass star with a mass of M-4 sin i(4) = 30-120 M-Jup. Using the mercury6 code, we find that such a system would be stable over more than 10(7) yr, in spite of the sizeable interaction. Our model fits the observed eclipse-time variations by the light-travel time effect alone, without invoking any additional process, and provides support for the planetary hypothesis of the eclipse-time variations in close binaries. The signature of non-Keplerian orbits may be visible in the data."],["dc.description.sponsorship","Alfried Krupp von Bohlen und Halbach Foundation, Essen"],["dc.identifier.doi","10.1051/0004-6361/201219391"],["dc.identifier.fs","596641"],["dc.identifier.isi","000306597200138"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/9610"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/26036"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Edp Sciences S A"],["dc.relation.issn","1432-0746"],["dc.relation.orgunit","Fakultät für Physik"],["dc.title","The quest for companions to post-common envelope binaries III. A reexamination of HW Virginis"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","821"],["dc.bibliographiccitation.issue","3"],["dc.bibliographiccitation.journal","Astronomy and Astrophysics"],["dc.bibliographiccitation.lastpage","827"],["dc.bibliographiccitation.volume","412"],["dc.contributor.author","Beuermann, Klaus"],["dc.contributor.author","Harrison, Thomas E."],["dc.contributor.author","McArthur, Barbara E."],["dc.contributor.author","Benedict, G. Fritz"],["dc.contributor.author","Gansicke, B. T."],["dc.date.accessioned","2018-11-07T10:34:13Z"],["dc.date.available","2018-11-07T10:34:13Z"],["dc.date.issued","2003"],["dc.description.abstract","Using the HST Fine Guidance Sensor, we have measured a high precision astrometric parallax of the cataclysmic variable EX Hydrae, pi = 15.50 +/- 0.29 mas. From the wavelength-integrated accretion-induced energy flux, we derive a quiescent accretion luminosity for EX Hya of L-acc = (2.6 +/- 0.6) x 10(32) erg s(-1). The quiescent accretion rate then is. (M) over dot(av) = (6.2 +/- 1.5) x 10(-11)(M-1/0.5 M.)(-1.61) M. yr(-1). The time-averaged accretion rate, which includes a small correction for the rare outbursts, is 6% higher. We discuss the system parameters of EX Hya and deduce M-1 = 0.4-0.7 M., M-2 = 0.07-0.10 M., and i = 76.0degrees - 77.6degrees, using recent radial velocity measurements of both components and restrictions imposed by other observational and theoretical constraints. We conclude that the secondary is undermassive, overluminous, and expanded over a ZAMS star of the same mass. Near the upper limit to M-1, the accretion rate of the white dwarf coincides with that due to near-equilibrium angular momentum loss by gravitational radiation and angular momentum transfer from the orbit into the spin-up of the white dwarf. Near the lower mass limit, the correspondingly higher accretion rate requires that either an additional angular momentum loss process is acting besides gravitational radiation or that accretion occurs on a near-adiabatic time scale. The latter possibility would imply that EX Hya is in a transient phase of high mass transfer and the associated spin-up of the white dwarf."],["dc.identifier.doi","10.1051/0004-6361:20031498"],["dc.identifier.isi","000187075500023"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/9807"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/44810"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Edp Sciences S A"],["dc.relation.issn","1432-0746"],["dc.relation.orgunit","Fakultät für Physik"],["dc.title","A precise HST parallax of the cataclysmic variable EX Hydrae, its system parameters, and accretion rate"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]