Desiderata for the Catalogue of Nearby Stars

1977 ◽  
Vol 35 ◽  
pp. 37-39
Author(s):  
W. Gliese
Keyword(s):  
The Sun ◽  
Royal Observatory ◽  
Trigonometric Parallaxes ◽  
Nearby Stars

In 1969 the second edition of the “Catalogue of Nearby Stars” was published. It contains 1529 single stars and systems with a total of 1890 components. The catalogue lists all stars with parallaxes equal to or larger than 0.”045. Only 1049 of these objects are nearer than 20 pc. The “Catalogue of Stars within 25 pc of the Sun”, published 1970 in the Royal Observatory Annals No. 5 consists of 1744 systems of which 1566 trigonometric parallaxes.

scholarly journals Luminosity of δ Scuti Stars After Hipparcos Satellite

1998 ◽  
Vol 11 (1) ◽  
pp. 567-567
Author(s):  
E. Antonello ◽  
L. Mantegazza ◽  
E. Poretti
Keyword(s):  
Globular Clusters ◽  
Rotational Velocity ◽  
High Amplitude ◽  
Empirical Dependence ◽  
Trigonometric Parallaxes ◽  
Nearby Stars ◽  
Observational Errors ◽  
Absolute Magnitudes ◽  
Scuti Stars ◽  
Δ Scuti Stars

The absolute magnitudes of δ Scuti stars derived from parallaxes measured by the Hipparcos satellite were compared with the previous estimates based on photometric uvby² indices, and significant differences were found which are related to photometric effects of metallicity and rotational velocity. A reliable calibration of Mv in terms of the photometric indices shall include an estimate of these effects. It is important also to take into account the possible presence of unresolved close companions in order to fully exploit the accuracy of Mv of nearby stars derived from the trigonometric parallaxes. The Mv of few bright SX Phe stars support the period-luminosity relation obtained with ground based observations of globular clusters, while it does not seem to confirm the empirical dependence of this relation on the metallicity. Some high amplitude δ Scuti stars with intermediate or normal metallicity and small and uncertain parallax have apparently a very low luminosity. Simulations of Mv determinations from observed parallaxes based on the discussion of observational errors by Lutz and Kelker (1973) have shown that the low luminosity could be an effect related to these errors.

scholarly journals XXXIV. Observations on the transit of Ve­nus, June the 6th, 1761, made in Spital-Square; the longitude of which is 4' 11" west of the Royal Observatory at Green­wich, and the latitude 51° 31' 15" north

1761 ◽  
Vol 52 ◽  
pp. 182-183
Keyword(s):  
The Sun ◽  
Royal Observatory ◽  
The Mean ◽  
The Difference ◽  
Made In

Having measured the diameter of Venus, on the sun, three times, with the object-glass micrometer, the mean was found to be 58 seconds; and but 6/10 of a second, the difference of the extremes.

scholarly journals A preliminary color-magnitude diagram for late-type stars in the solar neighborhood

1959 ◽  
Vol 10 ◽  
pp. 39-40
Author(s):  
O. C. Wilson
Keyword(s):  
Main Sequence ◽  
Star Clusters ◽  
Solar Neighborhood ◽  
Late Type ◽  
Main Sequence Stars ◽  
Individual Values ◽  
Magnitude Diagram ◽  
Trigonometric Parallaxes ◽  
Nearby Stars ◽  
The Mean

Modern photoelectric techniques yield magnitudes and colors of stars with accuracies of the order of a few thousandths and a few hundredths of a magnitude respectively. Hence for star clusters it is possible to derive highly accurate color-magnitude arrays since all of the members of a cluster may be considered to be at the same distance from the observer. It is much more difficult to do this for the nearby stars where all of the objects concerned are at different, and often poorly determined, distances. If one depends upon trigonometric parallaxes, the bulk of the reliable individual values will refer to main sequence stars, and while the mean luminosities of brighter stars are given reasonably well by this method, the scatter introduced into a color-magnitude array by using individual trigonometrically determined luminosities could obscure important features. Somewhat similar objections could be raised against the use of the usual spectroscopic parallaxes which also should be quite good for the main sequence but undoubtedly exhibit appreciable scatter for some, at least, of the brighter stars.

scholarly journals II. On a supposed periodicity in the elements of terrestrial mag­netism, with a period of 26 1/3 days

1872 ◽  
Vol 20 (130-138) ◽  
pp. 308-312 ◽  
Keyword(s):  
The Sun ◽  
Horizontal Force ◽  
Magnetic Elements ◽  
Royal Observatory ◽  
Imperial Academy ◽  
Meteorological Observations ◽  
Academy Of Sciences ◽  
Periodical Change

In a paper published in the ‘Proceedings of the Imperial Academy of Sciences of Vienna,’ vol. lxiv., Dr. Karl Hornstein has exhibited the results of a series of observations which appeared to show that the earths magnetism undergoes a periodical change in successive periods of 26 1/3 days, which might with great plausibility be referred to the rotation of the sun. It appeared to me that the deductions from the magnetic observations made at the Royal Observatory of Greenwich, and which are printed annually in the Greenwich Observations,’ or in the detached copies of ‘Results of Magnetical and Meteorological Observations made at the Royal Observatory of Greenwich, would afford good materials for testing the accuracy of this law, as applicable to a series of years. The mew results of the measured hourly ordinates of the terrestrial magnetic elements are given for every day, and it is certain that there has been no change of adjustments of the declination and horizontal-force instruments in the course of each year. For the horizontal-force instrument the temperature of the room has been maintained in a generally equable state, and in later years it has been remarkably uniform.

scholarly journals The Kinematics and Ages of Stars in Gliese’s Catalogue

1974 ◽  
Vol 3 ◽  
pp. 395-407 ◽  
Author(s):  
R. Wielen
Keyword(s):  
The Sun ◽  
Single Star ◽  
Nearby Stars

This contribution gives some results on the kinematics and ages of stars near the Sun. These results are mainly based on the catalogue of nearby stars compiled by Gliese (1957, 1969 and minor recent modifications). Table I shows the number of objects under consideration. While the old catalogue (1957) contained only stars with distances r up to 20 pc, the new edition (1969) includes many stars with slightly larger distances. In Table I, a ‘system’ is either a single star or a binary or a multiple system. The number of systems with known space velocities nearer than 20 pc has increased by about 30% from 1957 to 1969. The first edition of Gliese’s catalogue (1957) has been analyzed in detail by Gliese (1956) and von Hoerner (1960).

scholarly journals The Absolute Magnitudes of the Nearby Stars: Calibrations of mean luminosity relations

1985 ◽  
Vol 111 ◽  
pp. 369-372
Author(s):  
W. Gliese ◽  
H. Jahreiss
Keyword(s):  
Spectral Type ◽  
Trigonometric Parallaxes ◽  
Preliminary Version ◽  
Nearby Stars ◽  
The Absolute ◽  
Absolute Magnitudes

The nearby stars are most favored for determining precise absolute magnitudes and for calibrating spectral-type, luminosity relations and color, luminosity relations. To demonstrate the main problems we discuss the (Mv,B-V) relation since (B-V) data are available for most of our candidates. At Yale Observatory van Altena is compiling a new catalog of trigonometric parallaxes. We feel deeply indebted to van Altena for making available to us a preliminary version of this catalog.

scholarly journals A New Value for the Rotation Speed of the Spiral Structure

1977 ◽  
Vol 45 ◽  
pp. 293-296 ◽  
Author(s):  
J. Palouš
Keyword(s):  
Surface Density ◽  
Galactic Center ◽  
Local Density ◽  
Outer Part ◽  
Density Variation ◽  
The Sun ◽  
Basic Model ◽  
Rr Lyrae ◽  
The Galaxy ◽  
Nearby Stars

The basic model of our Galaxy, like the Schmidt (1965) model, obeys the density law ρ(R) for the Galaxy based on divers evidence, less or better known from observation. The interpretation of the interstellar hydrogen radio profiles yields the rotation curve and the run of the force component in the radial direction. The Oort constants A, B known from radial velocities and proper motions of nearby stars, the distance from the Sun to the galactic center Roestablished from the distances of RR Lyrae stars, the local density and density gradients in the vicinity of the Sun, known from the star counts, are involved in this basic model of the Galaxy. The r.m.s. velocity component in the z direction yields the approximate mass distribution in this direction. The model surface density is computed by integrating the density along the z direction in the model. The local surface density in the Schmidt model is 114 solar masses per pc2; it depends rather strongly on the assumed density variation in the outer part of the Galaxy.

scholarly journals Observation of the summer solstice, 1812, at the Royal Observatory

1832 ◽  
Vol 1 ◽  
pp. 443-444
Keyword(s):  
Plumb Line ◽  
Zenith Distance ◽  
The Sun ◽  
Summer Solstice ◽  
Royal Observatory ◽  
Point Of Departure

Since a minute description of the new circular instrument, which has been lately put up at Greenwich, is intended to be given to the Society as soon as it is completed in every respect, the Astronomer Royal takes no further notice of its construction than is necessary to show by what means the results of his observations of the sun at the last solstice was obtained. In other instruments, which take their point of departure from a plumb-line or level, the zenith distance of the sun is the primary ob­ject of investigation; and the polar distance of the sun, which is the ultimate object, is obtained by adding the co-latitude of the place, which completes the entire arc.

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