FRINK Linked Data Fragments server

Matches in SemOpenAlex for { <https://semopenalex.org/work/W1945765246> ?p ?o ?g. }

• W1945765246 endingPage "1540" @default.
• W1945765246 startingPage "1516" @default.
• W1945765246 abstract "We use nearby K dwarf stars to measure the helium-to-metal enrichment ratio ΔY/ΔZ, a diagnostic of the chemical history of the solar neighbourhood. Our sample of K dwarfs has homogeneously determined effective temperatures, bolometric luminosities and metallicities, allowing us to fit each star to the appropriate stellar isochrone and determine its helium content indirectly. We use a newly computed set of Padova isochrones which cover a wide range of helium and metal content. Our theoretical isochrones have been checked against a congruous set of main-sequence binaries with accurately measured masses, to discuss and validate their range of applicability. We find that the stellar masses deduced from the isochrones are usually in excellent agreement with empirical measurements. Good agreement is also found with empirical mass-luminosity relations. Despite fitting the masses of the stars very well, we find that anomalously low helium content (lower than primordial helium) is required to fit the luminosities and temperatures of the metal-poor K dwarfs, while more conventional values of the helium content are derived for the stars around solar metallicity. We have investigated the effect of diffusion in stellar models and the assumption of local thermodynamic equilibrium (LTE) in deriving metallicities. Neither of these is able to resolve the low-helium problem alone and only marginally if the cumulated effects are included, unless we assume a mixing-length which is strongly decreasing with metallicity. Further work in stellar models is urgently needed. The helium-to-metal enrichment ratio is found to be ΔY/ΔZ= 2.1 ± 0.9 around and above solar metallicity, consistent with previous studies, whereas open problems still remain at the lowest metallicities. Finally, we determine the helium content for a set of planetary host stars." @default.
• W1945765246 created "2016-06-24" @default.
• W1945765246 creator A5004695575 @default.
• W1945765246 creator A5010710369 @default.
• W1945765246 creator A5035316957 @default.
• W1945765246 creator A5045889594 @default.
• W1945765246 creator A5086796344 @default.
• W1945765246 date "2007-12-07" @default.
• W1945765246 modified "2023-10-03" @default.
• W1945765246 title "The helium abundance and ΔY/ΔZ in lower main-sequence stars" @default.
• W1945765246 cites W1485560057 @default.
• W1945765246 cites W1489995932 @default.
• W1945765246 cites W1509402453 @default.
• W1945765246 cites W1513591705 @default.
• W1945765246 cites W1515854972 @default.
• W1945765246 cites W1577858873 @default.
• W1945765246 cites W1610354098 @default.
• W1945765246 cites W195592436 @default.
• W1945765246 cites W1963735602 @default.
• W1945765246 cites W1963968906 @default.
• W1945765246 cites W1964007354 @default.
• W1945765246 cites W1967267230 @default.
• W1945765246 cites W1967911932 @default.
• W1945765246 cites W1972767493 @default.
• W1945765246 cites W1973059226 @default.
• W1945765246 cites W1973594330 @default.
• W1945765246 cites W1973693947 @default.
• W1945765246 cites W1979911750 @default.
• W1945765246 cites W1987730894 @default.
• W1945765246 cites W1987730961 @default.
• W1945765246 cites W1987954209 @default.
• W1945765246 cites W1988489301 @default.
• W1945765246 cites W1990554638 @default.
• W1945765246 cites W1992285003 @default.
• W1945765246 cites W1992491247 @default.
• W1945765246 cites W1992885010 @default.
• W1945765246 cites W1995519722 @default.
• W1945765246 cites W2000392429 @default.
• W1945765246 cites W2000573587 @default.
• W1945765246 cites W2002464564 @default.
• W1945765246 cites W2002876153 @default.
• W1945765246 cites W2004729284 @default.
• W1945765246 cites W2004807776 @default.
• W1945765246 cites W2007461470 @default.
• W1945765246 cites W2007852656 @default.
• W1945765246 cites W2009489905 @default.
• W1945765246 cites W2011573757 @default.
• W1945765246 cites W2012379477 @default.
• W1945765246 cites W2012853668 @default.
• W1945765246 cites W2014244408 @default.
• W1945765246 cites W2014519161 @default.
• W1945765246 cites W2015590058 @default.
• W1945765246 cites W2016972627 @default.
• W1945765246 cites W2017193313 @default.
• W1945765246 cites W2017430919 @default.
• W1945765246 cites W2017886612 @default.
• W1945765246 cites W2020288645 @default.
• W1945765246 cites W2020380401 @default.
• W1945765246 cites W2020693354 @default.
• W1945765246 cites W2023066093 @default.
• W1945765246 cites W2023967524 @default.
• W1945765246 cites W2029045219 @default.
• W1945765246 cites W2029164315 @default.
• W1945765246 cites W2029483560 @default.
• W1945765246 cites W2030798973 @default.
• W1945765246 cites W2031043816 @default.
• W1945765246 cites W2033142049 @default.
• W1945765246 cites W2033689492 @default.
• W1945765246 cites W2033821860 @default.
• W1945765246 cites W2036696684 @default.
• W1945765246 cites W2037953537 @default.
• W1945765246 cites W2039452097 @default.
• W1945765246 cites W2039725937 @default.
• W1945765246 cites W2039922125 @default.
• W1945765246 cites W2040367467 @default.
• W1945765246 cites W2043696205 @default.
• W1945765246 cites W2046154624 @default.
• W1945765246 cites W2046560422 @default.
• W1945765246 cites W2052112783 @default.
• W1945765246 cites W2052499397 @default.
• W1945765246 cites W2052683028 @default.
• W1945765246 cites W2054735865 @default.
• W1945765246 cites W2056932217 @default.
• W1945765246 cites W2059365121 @default.
• W1945765246 cites W2059763975 @default.
• W1945765246 cites W2060195076 @default.
• W1945765246 cites W2060991279 @default.
• W1945765246 cites W2064743375 @default.
• W1945765246 cites W2068892603 @default.
• W1945765246 cites W2071595644 @default.
• W1945765246 cites W2071599230 @default.
• W1945765246 cites W2071627235 @default.
• W1945765246 cites W2071631043 @default.
• W1945765246 cites W2072827550 @default.
• W1945765246 cites W2075715503 @default.
• W1945765246 cites W2076533122 @default.
• W1945765246 cites W2076616183 @default.
• W1945765246 cites W2077509233 @default.

• next