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The N2K Consortium. III. Short-Period Planets Orbiting HD 149143 and HD 109749
We report the detection of two short-period planets discovered at KeckObservatory. HD 149143 is a metal-rich G0 IV star with a planet ofMsini=1.33MJ and an orbital radius of 0.053 AU. The best-fitKeplerian model has an orbital period, P=4.072 days, semivelocityamplitude, K=149.6 m s-1, and eccentricity, e=0.016+/-0.01.The host star is chromospherically inactive and metal-rich, with[Fe/H]=0.26. Based on the Teff and stellar luminosity, wederive a stellar radius of 1.49 Rsolar. Photometricobservations of HD 149143 were carried out using the automatedphotometric telescopes at Fairborn Observatory. HD 149143 isphotometrically constant over the radial velocity period to0.0003+/-0.0002 mag, supporting the existence of the planetarycompanion. No transits were detected down to a photometric limit ofapproximately 0.02%, eliminating transiting planets with a variety ofcompositions and constraining the orbital inclination to less than83°. A short-period planet was also detected around HD 109749, a G3IV star. HD 109749 is chromospherically inactive, with [Fe/H]=0.25 and astellar radius of 1.24. The radial velocities for HD 109749 are modeledby a Keplerian with P=5.24 days and K=28.7 m s-1. Theinferred planet mass is Msini=0.28MJ and the semimajor axisof this orbit is 0.0635 AU. Photometry of HD 109749 was obtained withthe SMARTS consortium telescope, the PROMPT telescope, and bytransitsearch.org observers in Adelaide and Pretoria. These observationsdid not detect a decrement in the brightness of the host star at thepredicted ephemeris time, and they constrain the orbital inclination toless than 85° for gas giant planets with radii down to0.7RJ.Based on observations obtained at the W. M. Keck Observatory, which isoperated as a scientific partnership among the California Institute ofTechnology, the University of California, and the National Aeronauticsand Space Administration (NASA). The Observatory was made possible bythe generous financial support of the W. M. Keck Foundation. The authorswish to recognize and acknowledge the very significant cultural role andreverence that the summit of Mauna Kea has always had within theindigenous Hawaiian community. We are most fortunate to have theopportunity to conduct observations from this mountain. Keck time hasbeen granted by the National Optical Astronomy Observatory (NOAO) andNASA.
| The Geneva-Copenhagen survey of the Solar neighbourhood. Ages, metallicities, and kinematic properties of 14 000 F and G dwarfs
We present and discuss new determinations of metallicity, rotation, age,kinematics, and Galactic orbits for a complete, magnitude-limited, andkinematically unbiased sample of 16 682 nearby F and G dwarf stars. Our63 000 new, accurate radial-velocity observations for nearly 13 500stars allow identification of most of the binary stars in the sampleand, together with published uvbyβ photometry, Hipparcosparallaxes, Tycho-2 proper motions, and a few earlier radial velocities,complete the kinematic information for 14 139 stars. These high-qualityvelocity data are supplemented by effective temperatures andmetallicities newly derived from recent and/or revised calibrations. Theremaining stars either lack Hipparcos data or have fast rotation. Amajor effort has been devoted to the determination of new isochrone agesfor all stars for which this is possible. Particular attention has beengiven to a realistic treatment of statistical biases and errorestimates, as standard techniques tend to underestimate these effectsand introduce spurious features in the age distributions. Our ages agreewell with those by Edvardsson et al. (\cite{edv93}), despite severalastrophysical and computational improvements since then. We demonstrate,however, how strong observational and theoretical biases cause thedistribution of the observed ages to be very different from that of thetrue age distribution of the sample. Among the many basic relations ofthe Galactic disk that can be reinvestigated from the data presentedhere, we revisit the metallicity distribution of the G dwarfs and theage-metallicity, age-velocity, and metallicity-velocity relations of theSolar neighbourhood. Our first results confirm the lack of metal-poor Gdwarfs relative to closed-box model predictions (the ``G dwarfproblem''), the existence of radial metallicity gradients in the disk,the small change in mean metallicity of the thin disk since itsformation and the substantial scatter in metallicity at all ages, andthe continuing kinematic heating of the thin disk with an efficiencyconsistent with that expected for a combination of spiral arms and giantmolecular clouds. Distinct features in the distribution of the Vcomponent of the space motion are extended in age and metallicity,corresponding to the effects of stochastic spiral waves rather thanclassical moving groups, and may complicate the identification ofthick-disk stars from kinematic criteria. More advanced analyses of thisrich material will require careful simulations of the selection criteriafor the sample and the distribution of observational errors.Based on observations made with the Danish 1.5-m telescope at ESO, LaSilla, Chile, and with the Swiss 1-m telescope at Observatoire deHaute-Provence, France.Complete Tables 1 and 2 are only available in electronic form at the CDSvia anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/418/989
| Stroemgren photometry of F- and G-type stars brighter than V = 9.6. I. UVBY photometry
Within the framework of a large photometric observing program, designedto investigate the Galaxy's structure and evolution, Hβ photometryis being made for about 9000 stars. As a by-product, supplementary uvbyphotometry has been made. The results are presented in a cataloguecontaining 6924 uvby observations of 6190 stars, all south ofδ=+38deg. The overall internal rms errors of one observation(transformed to the standard system) of a program star in the interval6.5
| New UBVRI photometry for 900 supergiants
A description is presented of the results obtained in connection with asystematic program of supergiant photometry on the Johnson UBVRI system.During the eight years after the start of the program, almost 1000 starshave been observed, about 400 three or more times each. The originalselection of stars used the spectral type catalog of Jaschek et al.(1964) to choose supergiants. Since observations were possible from bothChile and Canada, no declination limits were imposed, and no particularselection criteria were imposed other than to eliminate carbon stars.These are so red as to require enormous extrapolations of thetransformation equations.
| Spectral types of stars with unusual photometric indices
The Kitt Peak 2.1-m Cassegrain spectrograph was used to obtain spectraof 92 A5-G0 stars measured by Olsen in the Stromgren four-color systemand predicted to be abnormal in the sense of excessive reddening, highluminosity, or abnormal composition. Of the five stars predicted to bereddened B or A stars, four were indeed such while for the fifth Olsenobserved the blended components. Of twelve stars predicted to besupergiants, one is a supergiant, four are giants, two are subgiants,three are Ap stars, and two are Am stars. Thus photometrically predictedsupergiants are actually stars above main sequence in two out of threecases but mostly much less luminous than expected. Of ten predictedweak-lined stars, only two were found to be really so. Am stars werewell predicted, though detection is contaminated with Ap and luminousstars. It is concluded that four-color photometry is useful in selectinginteresting stars, but is often unable to tell the specific type ofabnormality present.
| Estimation of spectral classifications for bright southern stars with interesting Stromgren indices
This paper investigates the degree of success with which uvby photometrycan be applied to predict spectral classifications for 947 A, F, and Gstars brighter than an apparent magnitude of 8.3 and with four-colorindices indicating some kind of interesting, unusual, or peculiarspectrum. One or several possible spectral classifications are estimatedfor each star from photometry alone, double stars are distinguished, andthe estimates are compared with published classifications. The resultsshow that the framework provided by uvby photometry can be extended toinclude most G and K stars, reddened stars, peculiar stars, and certaintypes of double star.
| MK classifications for F-and G-type stars. 3.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1974AJ.....79..682H&db_key=AST
| A catalogue of four-color photometry of late F-type stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1969AJ.....74..705P&db_key=AST
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משמש של הקבוצה הבאה
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תצפית ומידע אסטרומטרי
| קבוצת-כוכבים: | הרקולס |
| התרוממות ימנית: | 16h29m51.12s |
| סירוב: | +05°58'14.8" |
| גודל גלוי: | 6.914 |
| מרחק: | 133.511 פארסק |
| תנועה נכונה: | 7.3 |
| תנועה נכונה: | 3.9 |
| B-T magnitude: | 7.419 |
| V-T magnitude: | 6.956 |
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INHABITED SKY
