6,170 research outputs found

    Molecular hydrogen emission from W51

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    The detection of emission from the v = 1 approaches 0 S(1) quadrupole transition of H2 toward the cluster of intense infrared and H2O maser sources in W51 (north) is reported. The apparent luminosity of this line in W51 (north) is only about 4% of the luminosity of the same line toward the Kleinmann-Low infrared cluster in Orion; however, additional line-of-sight extinction and spatial extent of the source may account for the lower apparent power in W51. Similarity in the infrared and H2O properties of these clusters is addressed. The implications of the H2 emission for mass loss in the W51 region is discussed and some proposed models of radiation-driven mass outflow from pre-main sequence stars are briefly considered

    The Social Logic of Bounded Partisanship in Germany: A Comparison of Veteran Citizens (West Germans), New Citizens (East Germans) and Immigrants

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    That partisanship is bounded. Almost every West German, East German and immigrant never supports one or both of the major parties and most people vary support for their party by claiming no partisan preference. Hardly anyone ever selects each of the parties at different points in time. Immediate social networks join with social class and religious factors to structure partisanship. The same social logic underpins partisan choice among West Germans, East Germans, and immigrants, though factors unique to each population are also present.Partisanship; Germany; Social contexts; Partisanship in households; West Germans; East Germans; Immigrants; Probit Heckman selection model

    Probing the Low Mass Stellar End of the eta Chamaeleontis Cluster

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    We have identified three faint new members of the eta Chamaeleontis cluster. Spectral types of the new members are estimated to be ~M5 based on their TiO band strengths and broadband colors. With an age of 5-8 Myr for the cluster, masses of these new members are estimated to be ~0.08 Msun. All three display strong Li 6708A absorption and Halpha emission features including one with Halpha emission equivalent width ~60A along with HeI 6678 & 7605 A emission features that are characteristics of classical T Tauri stars.Comment: 11 pages, 4 figures, 2 tables, accepted in Ap

    The Tucana/Horologium, Columba, AB Doradus, and Argus Associations: New Members and Dusty Debris Disks

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    We propose 35 star systems within ~70 pc of Earth as newly identified members of nearby young stellar kinematic groups; these identifications include the first A- and late-B type members of the AB Doradus moving group and field Argus Association. All but one of the 35 systems contain a bright solar- or earlier-type star that should make an excellent target for the next generation of adaptive optics (AO) imaging systems on large telescopes. AO imaging has revealed four massive planets in orbit around the {\lambda} Boo star HR 8799. Initially the planets were of uncertain mass due in large part to the uncertain age of the star. We find that HR 8799 is a likely member of the ~30 Myr old Columba Association implying planet masses ~6 times that of Jupiter. We consider Spitzer Space Telescope MIPS photometry of stars in the ~30 Myr old Tucana/Horologium and Columba Associations, the ~40 Myr old field Argus Association, and the ~70 Myr old AB Doradus moving group. The percentage of stars in these young stellar groups that display excess emission above the stellar photosphere at 24 and 70 \mu m wavelengths - indicative of the presence of a dusty debris disk - is compared with corresponding percentages for members of 11 open clusters and stellar associations with ages between 8 and 750 Myr, thus elucidating the decay of debris disks with time.Comment: Accepted for publication in Ap

    Sensation Seeking and Perceived Need for Structure Moderate Soldiers’ Well-Being Before and After Operational Deployment

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    This study examined associations between sensation seeking and perceived need for structure, and changes in reported well-being among deployed soldiers. Participants (n = 167) were assessed before and after a six-month deployment to south Afghanistan. Results indicated that although well-being declined in the soldier sample as a whole following deployment, the degree of decrease was significantly different among soldiers with different personality profiles. Differences were moderated by soldiers’ level of sensation seeking and perceived need for structure. Results are discussed in terms of a person-environment fit theory in the context of preparation and rehabilitation of deployed military personnel
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