Abstract We present a multiplicity census for volume-complete all-sky survey of 422 stars with distances less than 25 pc and primary main-sequence effective temperatures T eff ≥ 5300 K. Very similar to previous results that have been presented various subsets this survey, we confirm the positive correlation stellar multiplicities mass. find F- G-type Population I 58% are non-single 21% in triple or higher level systems. For old intermediate-disk II stars—virtually all G type massive—even two...

As part of a homogeneous all-sky volume-complete sample half thousand solar-type stars within 25 pc we present census for the subset 150—mostly F-type stars—in mass range 1.1 M☉ ⩽ M 1.7 in terms their observed multiplicities. The major obstacle, as expected, arises from onset stellar rotation this it continues to support many hidden companions. Yet, solid increase fraction binary and higher level systems function primary is manifest. There even prospect that on account companion candidates...

Abstract High‐resolution spectroscopic observations of about 150 nearby stars or star systems are presented and discussed. The study these another 100 objects the previous papers this series implies that Galaxy became reality 13 14 Gyr ago with implementation a massive, rotationally‐supported population thick‐disk stars. very high formation rate in phase gave rise to rapid metal enrichment an expulsion gas supernovae‐driven Galactic winds, but was followed by gap for no less than three...

The Milky Way Galaxy has an age of about 13 billion years. Solar-type stars evolve all the long way to realm degenerate objects on essentially this time-scale. This, as well particular advantage that Sun offers through reliable differential spectroscopic analyses, render these ideal tracers for fossil record our parent spiral. Astrophysics is a science known be notoriously plagued by selection effects. present work – with major focus in fourth contribution model atmosphere analyses binaries...

This fifth in a series of papers finishes the model atmosphere analyses an unbiased, volume-complete sample more than 300 nearby solar-type stars. The first disintegrates into thick-disc and thin-disc stars on account their different distributions [Mg/H]–[Fe/Mg] chemical abundance plane. Detailed stellar age-datings locally few, but very relevant, subgiants show this map to be sequel major star formation gap hence legacy for two populations. Among thin disc subgiant 70 Vir with τ= 8.1 ± 0.6...

We present a study of the local stellar populations from volume-complete all-sky survey about 500 bright stars with distances less than 25 pc and down to main-sequence effective temperatures T-eff >= 5300 K. The sample is dominated by 93 per cent fraction Population I stars, only 22 sources (5 cent) are II 9 (2 intermediate-disc stars. No source belongs halo. By following mass instead their light, resulting subset 136 long-lived distributes as (16.2 cent): 6 (4.4 108 (79.4 for II:...

The Bochum Echelle Spectroscopic Observer BESO is a fibre-fed high-resolution spectrograph for the 1.5-m Hexapod Telescope at Cerro Armazones Observatory in Atacama desert Chile. Here we report on first observations and model atmosphere analyses of solar-type stars secured 2010 April. quality data tested with reflected sunlight spectrum as well standard G-type subgiant 70 Vir. We then investigate bright supposedly single F-type star ξ Gem present spectroscopic evidence that instead favours...

Abstract The very recent suggestion for the identification of a faint G-type subgiant, dubbed ‘Tycho G’, as binary progenitor Tycho Brahe's 1572 Type Ia supernova by Ruiz-Lapuente et al. is essentially based on peculiar space velocity star. Here we demonstrate that kinematics G are likewise in keeping with stars Milky Way's thick-disc population. Hence may well be seeing an object only coincidentally passing vicinity remnant, or Brahe and his contemporaries indeed have witnessed late...

Direct imaging observations of the solar-type star Gl 504 have recently uncovered a faint companion that, on supposition that host has an age Myr, was announced to be MJ Jovian exoplanet. Here we present observational evidence A is evolved turn-off about solar and by inference its low-mass brown dwarf. As with our previous work several years ago, suggest accretion substellar object account for otherwise unexplained high rotation A. We also propose distant B may now well facing driving agent...

The nearby subgiant HD 155358 has very recently been announced by Cochran et al. to harbour two Jovian-mass planetary companions and be the lowest metallicity exoplanet host star yet found. Here, we present a model atmosphere analysis stellar evolutionary tracks for 155358, demonstrate that it is actually member of ancient thick-disc population Milky Way (τ≥ 12 Gyr). As such, considerably rich in its α-chain nuclei, hence only about factor 2 below solar abundance terms these species. Yet, as...

In continuation of our previous study we present an updated census new companions and model atmosphere analyses for some 50 southern dwarfs, mostly in the mass range . For common-proper-motion μ Vir B, HR 2225 HD 67199 114853 confirm their physical association from radial velocities. We report discovery F-type visual binary α as a field blue straggler (ζ Ret, 5864) or identify (HD 67199, 4013, 8843) another five transfer systems candidates. F stars Eri 111 Tau, cases astrometric binaries by...

Optical spectra of the complexes, trans-ClCoN4CCC6H5, trans-CoN4(CCC6H5)2 and [graphic omitted]CoN4CC-p-C6H4CC[graphic omitted]n, (where N4= 3,9-dimethyl-4,8-diazaundecane-2,10-dione dioxime) show absorptions associated with π-π* transitions acetylenic unit indicate an extended π-electron conjugation through metal sites on chain in polymeric complex.

We present an H-band image of the companion Orionis taken with Keck adaptive optic system and NIRC 2 camera equipped a 300 mas-diameter coronographic mask. The direct detection this star enables us to calculate dynamical masses using only Kepler's laws (, ), study stellar evolutionary models at wide spread masses. application Baraffe et al. ([CITE]) pre-main-sequence implies age 70–130 Myrs. This is in conflict primary, confirmed member Ursa Major Cluster canonical As consequence, either low...

Detailed evolutionary tracks and basic stellar parameters for the nearby subgiants 104 Tau HD 168443 are presented discussed. Both serve as invaluable key stars accurate age-datings, especially they possess chemical signatures intermediate to of thick- thin-disc population. We derive τ= 9.7−0.6+0.8 Gyr 9.8−0.8+1.0 168443, very much in line with their local sibling HR 7569 at 9.1 ± 1.0 that was formerly Bernkopf, Fiedler & Fuhrmann. Both, thus add our sample rare but relevant disc formation...

We report on the bright and late F-type star HR 3138, which, with respect to its chemistry in [Mg/H]–[Fe/Mg] abundance plane, we identify as an old Population II member. Evolutionary tracks are, however, conflict this finding instead imply age of only τ = 5.6−1.8+ 2.2 Gyr (2σ) for 3138. discuss controversy light existing high-precision radial velocity surveys that mostly exclude case a blue straggler primary white dwarf secondary. While it is realized stellar merger can principally solve...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSQUID studies of α,ι-bis[(4,4'-cyanobiphenyl)oxy]alkanes and elucidation the orientational order parameterHidemine Furuya, Thomas Dries, Klaus Fuhrmann, Akihiro Abe, Matthias Ballauff, Erhard W. FischerCite this: Macromolecules 1990, 23, 18, 4122–4126Publication Date (Print):September 1, 1990Publication History Published online1 May 2002Published inissue 1 September...

We report the discovery of nearby single-lined and metal-poor F6V star HR 3220 as a field blue straggler from basic inconsistency τ≃ 3 Gyr evolutionary age compared to its low iron-to-magnesium abundance ratio which implies that must be instead old 10 Gyr. Our finding is corroborated by observational constraints spectroscopic astrometric P= 899 d orbit, leading secondary mass MB≃ 0.42+0.09− 0.05 M⊙ matches Rappaport et al. period-white dwarf relation case transfer system.

We report an intrinsically precise relation of the barium-to-iron enrichment as a function age for local, volume-complete (N = 30) sample ancient Population II (τ ≥ 12 Gyr) and intermediate-disc stars ≃ 10 Gyr), which suggests common, r-process-dominated nucleosynthesis site both elements in early stages Milky Way. Deviants from this empirical are to large extent identified formerly known or new blue straggler stars. particular striking case star HD 159062, whose barium overabundance is...