Graver (constellation)
See also: Graver (homonymy)
The Burin is a minor Constellation of the Southern hemisphere, wedged between the Éridan and the Colombe.
It is visible only starting from the south of the Europe and with this place only at the end of the Automne and in Hiver, close to the horizon.
History
The Graver is one of the 14 new constellations introduced by Nicolas-Louis de Lacaille in 1752. Its name comes from the proximity of the Sculpteur, whose graver would be a tool. However, Lacaille named this constellation “the Gravers”, but the two objects were molten thereafter in only one.
Observation of stars
The Graver is composed of star S slightly luminous of which four only are visible with the naked eye. It is a constellation without interest as regards the observation to the naked eye.; Localization of the constellation The graver is located between the Colombe and Éridan.
; Form constellation The stars of this constellation are very weak, and no form is really visible.
- From the nozzle of the dove: on the basis of α Col towards the West, one meets successively ε Col with ~2°, ο Col with ~2° in the same direction (a little more in north), and one falls finally on γ Cel (with ~3°) followed β Cel (with still ~4°).
- α Cel is located full South compared to β Cel, with approximately 4°.
- δ Cel is located at ~3° SSO of α Cel, and forms the Southern point of a small equilateral triangle with α Cel (in north) and α Hor (towards the west).
- For those which want to test their sight (and conditions of visibility), ζ Cel is a star magnitude 6.3 located at the north of β Cel. It is hardly visible, immediately with ~2° in the east of the couple ν1 ν 2 Eri.
Principal stars
See also: List of stars of the Graver
α Caeli
The most brilliant star of the constellation of the Graver is α Caeli and is however not particularly luminous since it reaches only the Magnitude connect 4,44.It is about a star doubles, his companion being a star of class M about magnitude 13. The primary elections resemble the Sun and its mass to 1,5 times the mass of this last is equal. His/her companion is smaller since it reaches only 0,3 times the mass of the Sun. These two stars are measured rather little, they would be distant one from the other of more than 1.000 UA and Orbite stripes in 130 years.
Other stars
γ Caeli, the 2nd star of the constellation with a magnitude of 4,55, is also double; his/her companion is magnitude 8,0.X Caeli is a variable star of the type δ Scuti (a type of pulsating stars, presenting very weak variations of luminosity over very short periods), its magnitude varies from 6,3 to 6,4 in 3:14 min. It was called before γ ² Caeli.
R Caeli, slightly in the south-west of β Caeli, is a variable star of type Mira, in the constellation of the Baleine. It passes from magnitude 6,7 to the magnitude 13,7 in 391 days.
Celestial objects
The Graver does not contain many brilliant objects of the deep sky: only two objects are more brilliant than the magnitude 13: NGC 1679, a Spiral galaxy located approximately two degrees at the south of ζ Caeli, and NGC 1567, another galaxy - elliptic this one - in the extreme-south of the galaxy (close to the borders with the Sea-bream and the Clock). Besides the Graver is nevertheless a rather dense constellation in galaxies and contains several tens of galaxy cluster of Abel.
See too
- List of stars of the Graver