Search for progenitors of supernovae type Ia with SPY

Napiwotzki, R.; Christlieb, N.; Drechsel, H.; Hagen, H. J.; Heber, U.; Homeier, D.; Karl, C.; Koester, D.; Leibundgut, B.; Marsh, T. R.; Moehler, S.; Nelemans, G.; Pauli, E.-M.; Reimers, D.; Renzini, A.; Yungelson, L. R.

doi:10.1002/1521-3994(200112)322:5/6<411::aid-asna411>3.0.co;2-i

Cited by 149 publications

(163 citation statements)

References 28 publications

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“…10 We obtained high resolution spectra of WD0137-349 as part of the SPY programme to identify the progenitors of Type Ia supernovae. 11 We noticed features in these spectra due to a low mass companion in a close orbit so we obtained further observations (shown in Figure 1) to measure the orbital period and mass ratio ( Table 1).…”

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confidence: 87%

Survival of a brown dwarf after engulfment by a red giant star

Maxted

Napiwotzki

Dobbie

et al. 2006

Nature

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Many sub-stellar companions (usually planets but also some brown dwarfs) have been identified orbiting solar-type stars. These stars can engulf their sub-stellar companions when they become red giants. This interaction may explain several outstanding problems in astrophysics 1-5 but is poorly understood, e.g., it is unclear under which conditions a low mass companion will evaporate, survive the interaction unchanged or gain mass. 1, 4, 5 Observational tests of models for this interaction have been hampered by a lack of positively identified remnants, i.e., white dwarf stars with close, sub-stellar companions. The companion to the prewhite dwarf AA Doradus may be a brown dwarf, but the uncertain history of this star and the extreme luminosity difference between the components make it difficult to interpret the observations or to put strong constraints on the models. 6, 7The magnetic white dwarf SDSS J121209.31+013627.7 may have a close brown dwarf companion 8 but little is known about this binary at present. Here we report the discovery of a brown dwarf in a short period orbit around a white dwarf. The properties of both stars in this binary can be directly observed and show that the brown dwarf was engulfed by a red giant but that this had little effect on it.

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mentioning

confidence: 87%

Survival of a brown dwarf after engulfment by a red giant star

Maxted

Napiwotzki

Dobbie

et al. 2006

Nature

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199

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“…Napiwotzki 2003 and references therein). The largest of these projects was the ESO SN Ia Progenitor Survey (SPY, Napiwotzki et al 2001b). The best known double degenerate SN Ia progenitor candidate system KPD 1930+2752 has an sdB primary 1 , which will become a white dwarf within about 10 8 yr before the merger occurs in about 2 × 10 8 yr (Maxted et al 2000a;Geier et al 2007).…”

Section: Sn Ia Progenitorsmentioning

confidence: 99%

Hot subdwarf stars in close-up view

Geier¹,

Heber²,

Podsiadlowski

et al. 2010

A&A

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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 phase of binary evolution. Since most of the known sdB systems are single-lined spectroscopic binaries, it is difficult to derive masses and unravel the companions' nature, which is the aim of this paper. Due to the tidal influence of the companion in close binary systems, the rotation of the primary becomes synchronised to its orbital motion. In this case it is possible to constrain the mass of the companion, if the primary mass, its projected rotational velocity as well as its surface gravity are known. For the first time we measured the projected rotational velocities of a large sdB binary sample from high resolution spectra. We analysed a sample of 51 sdB stars in close binaries, 40 of which have known orbital parameters comprising half of all such systems known today. Synchronisation in sdB binaries is discussed both from the theoretical and the observational point of view. The masses and the nature of the unseen companions could be constrained in 31 cases. We found orbital synchronisation most likely to be established in binaries with orbital periods shorter than 1.2 d. Only in five cases it was impossible to decide whether the sdB's companion is a white dwarf or an M dwarf. The companions to seven sdBs could be clearly identified as late M stars. One binary may have a brown dwarf companion. The unseen companions of nine sdBs are white dwarfs with typical masses. The mass of one white dwarf companion is very low. In eight cases (including the well known system KPD1930+2752) the companion mass exceeds 0.9 M , four of which even exceed the Chandrasekhar limit indicating that they may be neutron stars. Even stellar mass black holes are possible for the most massive companions. The distribution of the inclinations of the systems with low mass companions appears to be consistent with expectations, whereas a lack of high inclinations becomes obvious for the massive systems. We show that the formation of such systems can be explained with common envelope evolution and present an appropriate formation channel including two phases of unstable mass transfer and one supernova explosion. The sample also contains a candidate post-RGB star, which rotates fast despite its long orbital period. The post-RGB stars are expected to spin-up caused by their ongoing contraction. The age of the sdB is another important factor. If the EHB star is too young, the synchronisation process might not be finished yet. Estimating the ages of the target stars from their positions on the EHB band, we found PG 2345+318, which is known not to be synchronised, to lie near the zero-age extreme horizontal branch as are the massive candidates PG 1232−136, PG 1432+159 and PG 1101+249. These star may possibly be too young to have reached synchronisation. The derived large fraction of putative massive sdB binary systems ...

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“…Some additional objects come from the Montreal-Cambridge survey (Demers et al 1990;Lamontagne et al 2000) and from the Edinburgh-Cape survey (Kilkenny et al 1991). A detailed discussion of the target selection is given in Napiwotzki et al (2001Napiwotzki et al ( , 2003. While some of the input catalogs, e.g.…”

Section: Introductionmentioning

confidence: 99%

High-resolution UVES/VLT spectra of white dwarfs observed for the ESO SN Ia Progenitor Survey

Koester¹,

Voß

Napiwotzki

et al. 2009

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Context. The ESO Supernova Ia Progenitor Survey (SPY) took high-resolution spectra of more than 1000 white dwarfs and pre-white dwarfs. About two thirds of the stars observed are hydrogen-dominated DA white dwarfs. Here we present a catalog and detailed spectroscopic analysis of the DA stars in the SPY. Aims. Atmospheric parameters effective temperature and surface gravity are determined for normal DAs. Double-degenerate binaries, DAs with magnetic fields or dM companions, are classified and discussed. Methods. The spectra are compared with theoretical model atmospheres using a χ 2 fitting technique. Results. Our final sample contains 615 DAs, which show only hydrogen features in their spectra, although some are double-degenerate binaries. 187 are new detections or classifications. We also find 10 magnetic DAs (4 new) and 46 DA+dM pairs (10 new).

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Search for progenitors of supernovae type Ia with SPY

Cited by 149 publications

References 28 publications

Survival of a brown dwarf after engulfment by a red giant star

Survival of a brown dwarf after engulfment by a red giant star

Hot subdwarf stars in close-up view

High-resolution UVES/VLT spectra of white dwarfs observed for the ESO SN Ia Progenitor Survey

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