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Refined Parameters of the Planet Orbiting HD 189733
We report on the BVRI multiband follow-up photometry of the transitingextrasolar planet HD 189733b. We revise the transit parameters and finda planetary radius of RP=1.154+/-0.033RJ and aninclination of iP=85.79d+/-0.24d. The new density (~1 gcm-3) is significantly higher than the former estimate (~0.75g cm-3) this shows that from the current sample of ninetransiting planets, only HD 209458 (and possibly OGLE-10b) haveanomalously large radii and low densities. We note that due to theproximity of its parent star, HD 189733b currently has one of the mostprecise radius determinations among extrasolar planets. We calculate newephemerides, P=2.218573+/-0.000020 days andT0=2453629.39420+/-0.00024 (HJD), and estimate the timingoffsets of the 11 distinct transits with respect to the predictions of aconstant orbital period, which can be used to reveal the presence ofadditional planets in the system.
| The Henry Draper Extension Charts: A catalogue of accurate positions, proper motions, magnitudes and spectral types of 86933 stars
The Henry Draper Extension Charts (HDEC), published in the form offinding charts, provide spectral classification for some 87000 starsmostly between 10th and 11th magnitude. This data, being highlyvaluable, as yet was practically unusable for modern computer-basedastronomy. An earlier pilot project (Roeser et al. 1991) demonstrated apossibility to convert this into a star catalogue, using measurements ofcartesian coordinates of stars on the charts and positions of theAstrographic Catalogue (AC) for subsequent identification. We presenthere a final HDEC catalogue comprising accurate positions, propermotions, magnitudes and spectral classes for 86933 stars of the HenryDraper Extension Charts.
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Observation and Astrometry data
| Constellation: | Petit Renard |
| Right ascension: | 20h00m56.95s |
| Declination: | +22°50'49.1" |
| Apparent magnitude: | 8.094 |
| Distance: | 240.385 parsecs |
| Proper motion RA: | 14.7 |
| Proper motion Dec: | 1.7 |
| B-T magnitude: | 9.435 |
| V-T magnitude: | 8.205 |
Catalogs and designations:
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