Profiles of Strong Permitted Lines in Classical T Tauri Stars

We present a spectral analysis of 30 T Tauri stars observed with the Hamilton echelle spectrograph over more than a decade. One goal is to test magnetospheric accretion model predictions. Observational evidence previously published supporting the model, such as emission line asymmetry and a high frequency of redshifted absorption components, are considered. We also discuss the relation between different line forming regions and search for good accretion rate indicators. In this work we confirm several important points of the models, such as the correlation between accretion and outflow, broad emission components that are mostly central or slightly blueshifted and only the occasional presence of redshifted absorption. We also show, however, that the broad emission components supposedly formed in the magnetospheric accretion flow only partially support the models. Unlike the predictions, they are sometimes redshifted, and are mostly found to be symmetric. The published theoretical profiles do not have a strong resemblance to our observed ones. We emphasize the need for accretion models to include a strong turbulent component before their profiles will match the observations. The effects of rotation, and the outflow components, will also be needed to complete the picture.Comment: 25 pages including 9 figures, 3 tables, accepted for publication in the Astronomical Journa

Measuring Fundamental Parameters of Substellar Objects. II: Masses and Radii

We present mass and radius derivations for a sample of very young, mid- to late M, low-mass stellar and substellar objects in Upper Sco and Taurus. In a previous paper, we determined effective temperatures and surface gravities for these targets, from an analysis of their high-resolution optical spectra and comparisons to the latest synthetic spectra. We now derive extinctions, radii, masses and luminosities by combining our previous results with observed photometry, surface fluxes from the synthetic spectra and the known cluster distances. These are the first mass and radius estimates for young, very low mass bodies that are independent of theoretical evolutionary models (though our estimates do depend on spectral modeling). We find that for most of our sample, our derived mass-radius and mass-luminosity relationships are in very good agreement with the theoretical predictions. However, our results diverge from the evolutionary model values for the coolest, lowest-mass targets: our inferred radii and luminosities are significantly larger than predicted for these objects at the likely cluster ages, causing them to appear much younger than expected. We suggest that uncertainties in the evolutionary models - e.g., in the choice of initial conditions and/or treatment of interior convection - may be responsible for this discrepancy. Finally, two of our late-M objects (USco 128 and 130) appear to have masses close to the deuterium-fusion boundary (9--14 Jupiters, within a factor of 2). This conclusion is primarily a consequence of their considerable faintness compared to other targets with similar extinction, spectral type and temperature (difference of 1 mag). Our result suggests that the faintest young late-M or cooler objects may be significantly lower in mass than the current theoretical tracks indicate.Comment: 54 pages, incl. 5 figs, accepted Ap

The First Direct Measurements of Magnetic Fields on Very Low-Mass Stars

We present the first direct magnetic field measurements on M dwarfs cooler than spectral class M4.5. Utilizing a new method based on the effects of a field on the FeH band near 1 micron, we obtain information on whether the integrated surface magnetic flux (Bf) is low (well under 1 kilogauss), intermediate (between 1 and about 2.5 kG), or strong (greater than about 3 kG) on a set of stars ranging from M2 down to M9. We also measure the rotational broadening (vsini) and Halpha emission for more than 20 stars. Our goal is to advance the understanding of how dynamo field production varies with stellar parameters for very low-mass stars, how the field and emission activity are related, and whether there is a connection between the rotation and magnetic flux. We find that fields are produced throughout the M-dwarfs. Among the early M stars we have too few targets to yield conclusive results. In the mid-M stars, there is a clear connection between slow rotation and weak fields. In the late-M stars, rotation is always measureable, and the strongest fields go with the most rapid rotators. These very cool rapid rotators have the largest magnetic flux in the whole sample. Halpha emission is found to be a good general proxy for magnetic fields. The drop-off in fractional emission near the bottom of the main sequence is not accompanied by a drop-off in magnetic flux, lending credence to the hypothesis that it is due to atmospheric coupling to the field rather than changes in the field itself. It is clear that the methodology we have developed can be further applied to discover more about the behavior of magnetic dynamos and magnetic activity in cool and fully convective objects.Comment: 33 pages, accepted by ApJ, abstract abbreviated for astro-p

Pengobatan Tradisional Masyarakat Desa Lubuk Ambacang Kecamatan Hulu Kuantan Kabupataen Kuantan Singingi

Research on traditional medicine was conducted in the village of Lubuk Ambacang District of Hulu Kuantan Kuantan District Singingi. This research was conducted with the aim to explain how the belief systems that underlie the use of traditional medicine in the village of Lubuk Ambacang society and how the effective use of traditional medicine in the view of people in Desa Lubuk Ambacang. In this study the author uses qualitative research, is an attempt to present the social world, and perspective in life, in terms of concept, behavior, perception, and the question of human investigate. Data collection techniques using observation, interview and documentation. The research proves that became the foundations of society in the use of traditional herbs that is based on faith (Religion), hereditary tradition as well as fact-based reality has been perceived. While the effectiveness of the use of traditional herbs in the village of Lubuk Ambacang society there are positive that in the field of health, the economy and maintain the tradition of hereditary. There is also a negative effectiveness, such as a distorted belief, believe that the shaman could cure diseases suffered by the patient

Ultraviolet and X-ray detection of the 56 Peg system (KO 2p + WD)

Both IUE short and long wavelength exposures of the 56 Peg system are discussed. This mild barium star has an X-ray luminosity of 3 x 10 to the 31st power ergs/1, comparable to the rapidly rotating RS CVn binary systems, yet lies in a region of the HR diagram where stellar X-rays are generally not observed. This cool, bright giant is not a rapid rotator and the key to understanding its emission lies in the recent discovery of its white dwarf companion. Accretion onto the white dwarf of approximately 0.1% of the stellar wind of the primary is sufficient to power an X-ray source of the observed luminosity. Reprocessing of the X-rays in the cool dense stellar wind explains the origin of the UV emission line spectrum, and may explain the time varying asymmetry of the Mg 2 kappa line profile that is observed. Graphs which show observed fluxes and wavelengths are discussed

Deuterium-burning in substellar objects

We consider the depletion of primordial deuterium in the interior of substellar objects as a function of mass, age and absolute magnitude in several photometric passbands. We characterize potential spectroscopic signatures of deuterium in the lines of deuterated water HDO. These results will serve as a useful, independent diagnostic to characterize the mass and/or the age of young substellar objects, and to provide an independent age determination of very young clusters. These results can serve to identify objects at the deuterium-burning limit and to confront the theoretical prediction that D-burning is a necessary condition to form star-like objects.Comment: 13 pages, Latex file, uses aasms4.sty, accepted for publication in ApJ Letter

High resolution absolute flux profiles of the MC 2 h and k lines in evolved F8 to M5 stars

The central results of a survey of the Mg II resonance line emission in a sample of over 50 evolved late type stars, including spectral-luminosity type F8 to M5 and La to IV are presented. Observed and surface fluxes are derived and correlations noted. The major findings include: (1) Mg II k emission core asymmetry transition near K1 III, analogous to that known for Ca II K; (2) a small gravity and temperature dependence of the Mg II chromospheric radiative loss rate

Efektivitas Pemekaran Nagari Tandikek Utara Kecamatan Patamuan Kabupaten Padang Pariaman

Expansion is one of the effects phenomenon regional autonomy. Movementthe expansion of government admnistration area from top up level arrive down tolowest level namely the Villages in Minangkabau Culture at Province West Sumatra.The purpose are improving public service and the development of accelerated . In201o, expansion of north Tandikek the village with the status of increased ParamanTalang disk and Lubuk Laweh disk in accorded with together of agreement. Theproblems of this research are how the effectiveness of north Tandikek the VillagesPatamuan District Padang Pariaman Regency and the factors thats influence theeffectiveness.The research used effectiveness theory by Duncan. This theory consists ofthree variebel thats Achieved the goal, Integration and adaptation. The method ofthe research was qualitative using snowball sampling technique in selecting theinforman. Informan in this research Head Parts governmentof villages, headPatamuan District, Head North Tandikek Village and Community leaders northTandikek Villages.The result of this research it was found that effectivenesse expansion of northTandikek the village based on on the research conclusion enough effective. Based oneffectiveness theory by Duncan, evidently with many changes and significantprogress in alls area social,economy, education and culture in North TandikekVillage. The factors that influence are human resources, cooperation, facilities andinfrastructure and community participations. There was expansion get northTandikek the villages become the villages of progress and superior through trainingfoundationand the progressof human resources .Key word : Effectiveness, Expansion, village and North Tandikek the Villages

Evolutionary models for very-low-mass stars and brown dwarfs with dusty atmospheres

We present evolutionary calculations for very-low-mass stars and brown dwarfs based on synthetic spectra and non-grey atmosphere models which include dust formation and opacity, i.e. objects with \te\simle 2800 K. The interior of the most massive brown dwarfs is shown to develop a conductive core after $\sim 2$ Gyr which slows down their cooling. Comparison is made in optical and infrared color-magnitude diagrams with recent late-M and L-dwarf observations. The saturation in optical colors and the very red near-infrared colors of these objects are well explained by the onset of dust formation in the atmosphere. Comparison of the faintest presently observed L-dwarfs with these dusty evolutionary models suggests that dynamical processes such as turbulent diffusion and gravitational settling are taking place near the photosphere. As the effective temperature decreases below \te\approx 1300-1400 K, the colors of these objects move to very blue near-infrared colors, a consequence of the ongoing methane absorption in the infrared. We suggest the possibility ofa brown dwarf dearth in $J,H,K$ color-magnitude diagrams around this temperature.Comment: 38 pages, Latex file, uses aasms4.sty, accepted for publication in Ap