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Beaulieu JP Bennett DP Fouqué P Williams A Dominik M Jørgensen UG Kubas D Cassan A Coutures C Greenhill J Hill K Menzies J Sackett PD Albrow M Brillant S Caldwell JA Calitz JJ Cook KH Corrales E Desort M Dieters S Dominis D Donatowicz J Hoffman M Kane S Marquette JB Martin R Meintjes P Pollard K Sahu K Vinter C Wambsganss J Woller K Horne K Steele I Bramich DM Burgdorf M Snodgrass C Bode M Udalski A Szymański MK Kubiak M Wieckowski T Pietrzyński G Soszyński I Szewczyk O Wyrzykowski L 《Nature》2006,439(7075):437-440
In the favoured core-accretion model of formation of planetary systems, solid planetesimals accumulate to build up planetary cores, which then accrete nebular gas if they are sufficiently massive. Around M-dwarf stars (the most common stars in our Galaxy), this model favours the formation of Earth-mass (M(o)) to Neptune-mass planets with orbital radii of 1 to 10 astronomical units (au), which is consistent with the small number of gas giant planets known to orbit M-dwarf host stars. More than 170 extrasolar planets have been discovered with a wide range of masses and orbital periods, but planets of Neptune's mass or less have not hitherto been detected at separations of more than 0.15 au from normal stars. Here we report the discovery of a 5.5(+5.5)(-2.7) M(o) planetary companion at a separation of 2.6+1.5-0.6 au from a 0.22+0.21-0.11 M(o) M-dwarf star, where M(o) refers to a solar mass. (We propose to name it OGLE-2005-BLG-390Lb, indicating a planetary mass companion to the lens star of the microlensing event.) The mass is lower than that of GJ876d (ref. 5), although the error bars overlap. Our detection suggests that such cool, sub-Neptune-mass planets may be more common than gas giant planets, as predicted by the core accretion theory. 相似文献
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A quaternary ammonium compound containing amino acid residue was synthesized by Converting 3-chloro-2-hydroxy-propyalkyldimethylammonium chlorides into its epoxide derivatives, then attaching an amino acid to the epoxide derivatives synthesized a quaternary ammonium compound containing amino acid residue. Modified dyes were prepared by the ionotropy of anionic dyes with the quaternary ammonium compound containing amino acid residue. It was discovered that the modified dyes exhibited an excellent pH controllable solubility. These modified dyes have good water solubility at pH> 8.0, but they were water insoluble at pH < 6.5. On the printing paper, modified dyes in water-based ink-jet print ink could convert to water insoluble form and give prints excellent water fastness. 相似文献
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