Star catalogue

A star catalogue, or star catalog, is an astronomical catalogue that lists stars. In astronomy, many stars are referred to simply by catalogue numbers. There are a great many different star catalogues which have been produced for different purposes over the years, and this article covers only some of the more frequently quoted ones. Star catalogues were compiled by many different ancient peoples, including the Babylonians, Greeks, Chinese, Persians, and Arabs. Most modern catalogues are available in electronic format and can be freely downloaded from NASA's Astronomical Data Center.

Completeness and accuracy is described by the weakest apparent magnitude V (largest number) and the accuracy of the positions.

Historical catalogues

Ancient Near East

From their existing records, it is known that the ancient Egyptians recorded the names of only a few identifiable constellations and a list of thirty-six decans that were used as a star clock. The Egyptians called the circumpolar star 'the star that cannot perish' and, although they made no known formal star catalogues, they nonetheless created extensive star charts of the night sky which adorn the coffins and ceilings of tomb chambers.

ADS 48

ADS 48 is a multiple star system in the constellation of Andromeda consisting of 7 stars. The components, in order from A to G, have apparent visual magnitudes of 8.83, 9.00, 13.30, 12.53, 11.68, 9.97, and 13.00.

ADS 48A and ADS 48B are in orbital motion around each other while ADS 48F is a common proper motion companion. The others are unassociated background stars.

References

Eta Corvi

Eta Corvi (Eta Crv, η Corvi, η Crv) is an F-type main-sequence star, the sixth-brightest star in the constellation of Corvus. Two debris disks have been detected orbiting this star, one warm within a few astronomical units (AU) and another out at ~150 AU.

Properties

Eta Corvi is only about 30% of the Sun's age. The concentration of iron in its atmosphere is only about 93% that of the Sun's. The projected rotational velocity at the equator (v sin i) is a brisk 68 km/s. A yellow-white main sequence star of spectral type F2V, it has an estimated surface temperature of 6950 K. It is 1.52 times as massive as the Sun and is 4.87 times as luminous. It is 59 light-years distant from our Solar System.

The IRAS satellite detected an excess of infrared radiation from this star, beyond what would normally be expected for a stellar object of this class. Observations in the submillimetre band confirmed the presence of excess dust in orbit around the star having about 60% of the mass of the Moon and a temperature of 80 K. The data indicated a debris disk with an estimated maximum radius of 180 AU from the star, or 180 times the separation of Earth and the Sun. (Compare to the Kuiper belt, which extends out to 55 AU from the Sun.)