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TRIMOR - three-dimensional correlation technique to analyse multi-order spectra of triple stellar systems: application to HD188753
This paper presents a new algorithm, TRIMOR, to analyse multi-orderspectra of triple systems. The algorithm is an extension of TRICOR, thethree-dimensional correlation technique that derives the radialvelocities of triple stellar systems from single-order spectra. Thecombined correlation derived from many orders enables the detection andthe measurement of radial velocities of faint tertiary companions. Thepaper applied TRIMOR to the already available spectra of HD188753, awell-known triple system, yielding the radial velocities of the fainteststar in the system. This rendered the close pair of the triple system adouble-lined spectroscopic binary, which led to a precise mass ratio andan estimate of its inclination. The close-pair inclination is very closeto the inclination of the wide orbit, consistent with the assertion thatthis triple system has a close to coplanar configuration.
| No evidence of a hot Jupiter around HD 188753 A
Context: The discovery of a short-period giant planet (a hot Jupiter)around the primary component of the triple star system HD 188753 hasoften been considered as an important observational evidence and as aserious challenge to planet-formation theories. Aims: Followingthis discovery, we monitored HD 188753 during one year to bettercharacterize the planetary orbit and the feasibility of planet searchesin close binaries and multiple star systems. Methods: We obtainedDoppler measurements of HD 188753 with the ELODIE spectrograph at theObservatoire de Haute-Provence. We then extracted radial velocities forthe two brightest components of the system using our multi-order,two-dimensional correlation algorithm, TODCOR. Results: Ourobservations and analysis do not confirm the existence of theshort-period giant planet previously reported around HD 188753 A. MonteCarlo simulations show that we had both the precision and the temporalsampling required to detect a planetary signal like the one quoted. Conclusions: From our failure to detect the presumed planet around HD188753 A and from the available data on HD 188753, we conclude thatthere is currently no convincing evidence of a close-in giant planetaround HD 188753 A.Based on observations collected at the Observatoire de Haute-Provencewith the ELODIE echelle spectrograph mounted on the 1.93-m telescope.Table 1 is only available in electronic form at http://www.aanda.org
| Improved Astrometry and Photometry for the Luyten Catalog. II. Faint Stars and the Revised Catalog
We complete construction of a catalog containing improved astrometry andnew optical/infrared photometry for the vast majority of NLTT starslying in the overlap of regions covered by POSS I and by the secondincremental Two Micron All Sky Survey (2MASS) release, approximately 44%of the sky. The epoch 2000 positions are typically accurate to 130 mas,the proper motions to 5.5 mas yr-1, and the V-J colors to0.25 mag. Relative proper motions of binary components are measured to 3mas yr-1. The false-identification rate is ~1% for11<~V<~18 and substantially less at brighter magnitudes. Theseimprovements permit the construction of a reduced proper-motion diagramthat, for the first time, allows one to classify NLTT stars intomain-sequence (MS) stars, subdwarfs (SDs), and white dwarfs (WDs). We inturn use this diagram to analyze the properties of both our catalog andthe NLTT catalog on which it is based. In sharp contrast to popularbelief, we find that NLTT incompleteness in the plane is almostcompletely concentrated in MS stars, and that SDs and WDs are detectedalmost uniformly over the sky δ>-33deg. Our catalogwill therefore provide a powerful tool to probe these populationsstatistically, as well as to reliably identify individual SDs and WDs.
| The general catalogue of trigonometric [stellar] paralaxes
Not Available
| Photoelectric Three Colour Magnitudes for Southern Stars
Not Available
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Observation and Astrometry data
| Constellation: | Phoenix |
| Right ascension: | 00h04m24.88s |
| Declination: | -47°04'05.0" |
| Apparent magnitude: | 9.783 |
| Distance: | 44.405 parsecs |
| Proper motion RA: | 293 |
| Proper motion Dec: | 35.7 |
| B-T magnitude: | 10.785 |
| V-T magnitude: | 9.866 |
Catalogs and designations:
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