Delta Scorpii
Encyclopedia
Delta Scorpii is a star
in the constellation
Scorpius
. It has the traditional name Dschubba (or Dzuba, from Arabic jabhat, "forehead" (of the scorpion
) or also Iclarcrau or Iclarkrav.
Because Delta Scorpii is near the ecliptic
it is occasionally occulted
by the Moon
, or (extremely rarely) by planet
s.
. Spectra taken after the outburst began have shown that Delta Sco is throwing off luminous gases from its equatorial region. As of 2005 the flareup continues. Although the brightness varies, it remains well above its previous constant magnitude.
to Mercury
. Furthermore, there is a star that takes about 10 years to orbit Dschubba in a highly eccentric
orbit that takes it close in to the primary once a decade. The last close encounter of these two stars happened in mid-2000 and it may have triggered the outburst of the primary star. A possible fourth companion star lies at about twice the distance again from the main star.
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
in the constellation
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....
Scorpius
Scorpius
Scorpius, sometimes known as Scorpio, is one of the constellations of the zodiac. Its name is Latin for scorpion, and its symbol is . It lies between Libra to the west and Sagittarius to the east...
. It has the traditional name Dschubba (or Dzuba, from Arabic jabhat, "forehead" (of the scorpion
Scorpion
Scorpions are predatory arthropod animals of the order Scorpiones within the class Arachnida. They have eight legs and are easily recognized by the pair of grasping claws and the narrow, segmented tail, often carried in a characteristic forward curve over the back, ending with a venomous stinger...
) or also Iclarcrau or Iclarkrav.
Because Delta Scorpii is near the ecliptic
Ecliptic
The ecliptic is the plane of the earth's orbit around the sun. In more accurate terms, it is the intersection of the celestial sphere with the ecliptic plane, which is the geometric plane containing the mean orbit of the Earth around the Sun...
it is occasionally occulted
Occultation
An occultation is an event that occurs when one object is hidden by another object that passes between it and the observer. The word is used in astronomy . It can also refer to any situation wherein an object in the foreground blocks from view an object in the background...
by the Moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...
, or (extremely rarely) by planet
Planet
A planet is a celestial body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.The term planet is ancient, with ties to history, science,...
s.
Variability
In June 2000, Delta Scorpii was observed by Sebastian Otero to be 0.1 magnitudes brighter than normal. Its brightness has varied since then and has reached as high as magnitude 1.6 or 1.7, altering the familiar appearance of ScorpiusScorpius
Scorpius, sometimes known as Scorpio, is one of the constellations of the zodiac. Its name is Latin for scorpion, and its symbol is . It lies between Libra to the west and Sagittarius to the east...
. Spectra taken after the outburst began have shown that Delta Sco is throwing off luminous gases from its equatorial region. As of 2005 the flareup continues. Although the brightness varies, it remains well above its previous constant magnitude.
Companion stars
Dschubba is accompanied by a class B star that orbits the primary every 20 days at a distance comparable to the distance from the SunSun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
to Mercury
Mercury (planet)
Mercury is the innermost and smallest planet in the Solar System, orbiting the Sun once every 87.969 Earth days. The orbit of Mercury has the highest eccentricity of all the Solar System planets, and it has the smallest axial tilt. It completes three rotations about its axis for every two orbits...
. Furthermore, there is a star that takes about 10 years to orbit Dschubba in a highly eccentric
Eccentricity (mathematics)
In mathematics, the eccentricity, denoted e or \varepsilon, is a parameter associated with every conic section. It can be thought of as a measure of how much the conic section deviates from being circular.In particular,...
orbit that takes it close in to the primary once a decade. The last close encounter of these two stars happened in mid-2000 and it may have triggered the outburst of the primary star. A possible fourth companion star lies at about twice the distance again from the main star.
External links
- *Jim Kaler's Stars, University of Illinois: Dschubba
- Delta Scorpii brighter than ever (Sky and Telescope, February 4, 2002)
- Delta Scorpii still showing off (Sky and Telescope, June 25, 2003)