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How Eccentric Orbital Solutions Can Hide Planetary Systems in 2:1 Resonant Orbits
The Doppler technique measures the reflex radial motion of a starinduced by the presence of companions and is the most successful methodto detect exoplanets. If several planets are present, their signals willappear combined in the radial motion of the star, leading to potentialmisinterpretations of the data. Specifically, two planets in 2:1resonant orbits can mimic the signal of a single planet in an eccentricorbit. We quantify the implications of this statistical degeneracy for arepresentative sample of the reported single exoplanets with availabledata sets, finding that (1) around 35% of the published eccentricone-planet solutions are statistically indistinguishable from planetarysystems in 2:1 orbital resonance, (2) another 40% cannot bestatistically distinguished from a circular orbital solution, and (3)planets with masses comparable to Earth could be hidden in known orbitalsolutions of eccentric super-Earths and Neptune mass planets.
| A large, complete, volume-limited sample of G-type dwarfs. I. Completion of Stroemgren UVBY photometry
Four-colour photometry of potential dwarf stars of types G0 to K2,selected from the Michigan Spectral Catalogues (Vol. 1-3), has beencarried out. The results are presented in a catalogue containing 4247uvby observations of 3900 stars, all south of δ = -26deg. Theoverall internal rms errors of one observation (transformed to thestandard system) of a program star in the interval 8.5 < V < 10.5are 0.0044, 0.0021, 0.0039, and 0.0059, respectively, in V, b-y, m_1_ ,and c_1_. The purpose of the catalogue, combined with earliercatalogues, is to allow selection of a large, complete, volume-limitedsample of G- and K-type dwarfs, investigate their metallicitydistribution, and compare it to predictions of various models ofgalactic chemical evolution. Future papers in this series will discussthese subjects.
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Observation and Astrometry data
| Constellation: | Tucana |
| Right ascension: | 23h43m57.23s |
| Declination: | -65°29'26.3" |
| Apparent magnitude: | 9.139 |
| Proper motion RA: | 2.5 |
| Proper motion Dec: | -21 |
| B-T magnitude: | 10.457 |
| V-T magnitude: | 9.248 |
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