Садржај
Слике
Уплоадјуј своје слике
DSS Images Other Images
Везани чланци
Catalog of Nearby Exoplanets
We present a catalog of nearby exoplanets. It contains the 172 knownlow-mass companions with orbits established through radial velocity andtransit measurements around stars within 200 pc. We include fivepreviously unpublished exoplanets orbiting the stars HD 11964, HD 66428,HD 99109, HD 107148, and HD 164922. We update orbits for 83 additionalexoplanets, including many whose orbits have not been revised sincetheir announcement, and include radial velocity time series from theLick, Keck, and Anglo-Australian Observatory planet searches. Both thesenew and previously published velocities are more precise here due toimprovements in our data reduction pipeline, which we applied toarchival spectra. We present a brief summary of the global properties ofthe known exoplanets, including their distributions of orbital semimajoraxis, minimum mass, and orbital eccentricity.Based on observations obtained at the W. M. Keck Observatory, which isoperated jointly by the University of California and the CaliforniaInstitute of Technology. The Keck Observatory was made possible by thegenerous financial support of the W. M. Keck Foundation.
| Elodie metallicity-biased search for transiting Hot Jupiters. I. Two Hot Jupiters orbiting the slightly evolved stars HD 118203 and HD 149143
We report the discovery of a new planet candidate orbiting the subgiantstar HD 118203 with a period of P = 6.1335 days. Thebest Keplerian solution yields an eccentricity e = 0.31 and a minimummass m_2 sin{i} = 2.1 M_Jup for the planet. This star has been observedwith the ELODIE fiber-fed spectrograph as one of the targets in ourplanet-search programme biased toward high-metallicity stars, on-goingsince March 2004 at the Haute-Provence Observatory. An analysis of thespectroscopic line profiles using line bisectors revealed no correlationbetween the radial velocities and the line-bisector orientations,indicating that the periodic radial-velocity signal is best explained bythe presence of a planet-mass companion. A linear trend is observed inthe residuals around the orbital solution that could be explained by thepresence of a second companion in a longer-period orbit. We also presenthere our orbital solution for another slightly evolved star in ourmetal-rich sample, HD 149143, recently proposed tohost a 4-d period Hot Jupiter by the N2K consortium. Our solution yieldsa period P = 4.09 days, a marginally significant eccentricity e = 0.08and a planetary minimum mass of 1.36 M_Jup. We checked that the shape ofthe spectral lines does not vary for this star as well.
| ELODIE metallicity-biased search for transiting Hot Jupiters. II. A very hot Jupiter transiting the bright K star HD 189733
Context: .Among the 160 known exoplanets, mainly detected in largeradial-velocity surveys, only 8 have a characterization of their actualmass and radius thanks to the two complementary methods of detection:radial velocities and photometric transit. Aims: .We started inMarch 2004 an exoplanet-search programme biased toward high-metallicitystars which are more frequently host extra-solar planets. This surveyaims to detect close-in giant planets, which are most likely to transittheir host star. Methods: .For this programme, high-precisionradial velocities are measured with the ELODIE fiber-fed spectrograph onthe 1.93-m telescope, and high-precision photometry is obtained with theCCD Camera on the 1.20-m telescope, both at the Haute-ProvenceObservatory. Results: .We report here the discovery of a newtransiting hot Jupiter orbiting the star HD 189733. The planetary natureof this object is confirmed by the observation of both the spectroscopicand photometric transits. The exoplanet HD 189733 b, with an orbitalperiod of 2.219 days, has one of the shortest orbital periods detectedby radial velocities, and presents the largest photometric depth in thelight curve (3%) observed to date. We estimate for the planet amass of 1.15±0.04 MJ and a radius of 1.26±0.03RJ. Considering that HD 189733 has the same visual magnitudeas the well known exoplanet host star HD 209458, further ground-basedand space-based follow-up observations are very promising and willpermit a characterization of the atmosphere and exosphere of this giantexoplanet.
| Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters
The availability of the Hipparcos Catalogue has triggered many kinematicand dynamical studies of the solar neighbourhood. Nevertheless, thosestudies generally lacked the third component of the space velocities,i.e., the radial velocities. This work presents the kinematic analysisof 5952 K and 739 M giants in the solar neighbourhood which includes forthe first time radial velocity data from a large survey performed withthe CORAVEL spectrovelocimeter. It also uses proper motions from theTycho-2 catalogue, which are expected to be more accurate than theHipparcos ones. An important by-product of this study is the observedfraction of only 5.7% of spectroscopic binaries among M giants ascompared to 13.7% for K giants. After excluding the binaries for whichno center-of-mass velocity could be estimated, 5311 K and 719 M giantsremain in the final sample. The UV-plane constructed from these datafor the stars with precise parallaxes (σπ/π≤20%) reveals a rich small-scale structure, with several clumpscorresponding to the Hercules stream, the Sirius moving group, and theHyades and Pleiades superclusters. A maximum-likelihood method, based ona Bayesian approach, has been applied to the data, in order to make fulluse of all the available stars (not only those with precise parallaxes)and to derive the kinematic properties of these subgroups. Isochrones inthe Hertzsprung-Russell diagram reveal a very wide range of ages forstars belonging to these groups. These groups are most probably relatedto the dynamical perturbation by transient spiral waves (as recentlymodelled by De Simone et al. \cite{Simone2004}) rather than to clusterremnants. A possible explanation for the presence of younggroup/clusters in the same area of the UV-plane is that they have beenput there by the spiral wave associated with their formation, while thekinematics of the older stars of our sample has also been disturbed bythe same wave. The emerging picture is thus one of dynamical streamspervading the solar neighbourhood and travelling in the Galaxy withsimilar space velocities. The term dynamical stream is more appropriatethan the traditional term supercluster since it involves stars ofdifferent ages, not born at the same place nor at the same time. Theposition of those streams in the UV-plane is responsible for the vertexdeviation of 16.2o ± 5.6o for the wholesample. Our study suggests that the vertex deviation for youngerpopulations could have the same dynamical origin. The underlyingvelocity ellipsoid, extracted by the maximum-likelihood method afterremoval of the streams, is not centered on the value commonly acceptedfor the radial antisolar motion: it is centered on < U > =-2.78±1.07 km s-1. However, the full data set(including the various streams) does yield the usual value for theradial solar motion, when properly accounting for the biases inherent tothis kind of analysis (namely, < U > = -10.25±0.15 kms-1). This discrepancy clearly raises the essential questionof how to derive the solar motion in the presence of dynamicalperturbations altering the kinematics of the solar neighbourhood: doesthere exist in the solar neighbourhood a subset of stars having no netradial motion which can be used as a reference against which to measurethe solar motion?Based on observations performed at the Swiss 1m-telescope at OHP,France, and on data from the ESA Hipparcos astrometry satellite.Full Table \ref{taba1} is 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/430/165}
|
Додај нови чланак
Линкови у сродству са темом
Додај нови линк
Чланови следећих група \:
|
Посматрања и Астрометриски подаци
| Сазвежђа: | Велики медвед |
| Ректацензија: | 13h34m02.54s |
| Deклинација: | +53°43'42.7" |
| Apparent магнитуда: | 8.065 |
| Даљина: | 88.574 parsecs |
| Proper motion RA: | -84.7 |
| Proper motion Dec: | -79.7 |
| B-T magnitude: | 8.903 |
| V-T magnitude: | 8.135 |
Каталог и designations:
|
