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The companion of HD 190228: Planet or brown dwarf?
A detailed abundance analysis has been carried out from high-resolution,high signal-to-noise spectra of the G5IV star HD190228, which is announced to harbor an extrasolar planet withMPsin i of 5.0 MJ and an orbital period of 1127days. Based on the model atmosphere of Teff=5180 K, {log g}=3.7, xit =1.3 km s-1, we obtained [Fe/H]=-0.40,which puts it on the metal-poor tail of the metallicity distribution ofthe so far discovered 48 planet-harboring stars. The relative abundance,[X/Fe], indicates an overabundance of light elements (O, Na, Mg, Al, Si,S, Sc) by 0.1-0.2 dex and the solar abundance of heavier elements (K,Ca, Ti, V, Cr, Mn, Ni, Ba). These elements show no conspicuousanomalies. The solar [C/Fe] seems to be slightly smaller than theaverage (but within the scatter) of field stars of the same [Fe/H], andthere is no clear trend of [X/H] with condensation temperature of theelement. Neither the process of planet formation nor the stellardilution during the subgiant stage seems to have polluted its chemicalcomposition. The initially low metallicity may be explained by thesuggestion that HD 190228 is accompanied by a browndwarf instead of a planet. Based on observation carried out at BeijingAstronomical Observatory (Xinglong, PR China).
| Two-colour photometry for 9473 components of close Hipparcos double and multiple stars
Using observations obtained with the Tycho instrument of the ESAHipparcos satellite, a two-colour photometry is produced for componentsof more than 7 000 Hipparcos double and multiple stars with angularseparations 0.1 to 2.5 arcsec. We publish 9473 components of 5173systems with separations above 0.3 arcsec. The majority of them did nothave Tycho photometry in the Hipparcos catalogue. The magnitudes arederived in the Tycho B_T and V_T passbands, similar to the Johnsonpassbands. Photometrically resolved components of the binaries withstatistically significant trigonometric parallaxes can be put on an HRdiagram, the majority of them for the first time. Based on observationsmade with the ESA Hipparcos satellite.
| ICCD Speckle Observations of Binary Stars. XIII. Measurements During 1989- 1994 From the Cerro Tololo 4 M Telescope
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1996AJ....111..936H&db_key=AST
| ICCD speckle observations of binary stars. VIII - Measurements during 1989-1991 from the Cerro Tololo 4 M telescope
One-thousand eighty-eight observations of 947 binary star systems,observed by means of speckle interferometry with the 4 m telescope onCerro Tololo, are presented. These measurements, made during the period1989-1991, comprise the second installment of results stemming from theexpansion of our speckle program to the southern hemisphere.
| Micrometric measurements of southern double stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1983A&AS...53..177A&db_key=AST
| Measures of southern visual double stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1978PASP...90..587H&db_key=AST
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משמש של הקבוצה הבאה
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תצפית ומידע אסטרומטרי
| קבוצת-כוכבים: | ארידנוס |
| התרוממות ימנית: | 01h43m01.08s |
| סירוב: | -54°51'23.5" |
| גודל גלוי: | 8.827 |
| מרחק: | 173.01 פארסק |
| תנועה נכונה: | -11.6 |
| תנועה נכונה: | -18.4 |
| B-T magnitude: | 9.39 |
| V-T magnitude: | 8.874 |
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