Delta Scuti
Encyclopedia
Delta Scuti is a white, F-type
giant star
in the constellation
Scutum
. It is approximately 187 light years
from Earth
. Delta Scuti is the prototype of the Delta Scuti type
variable star
s. It is a high-amplitude δ Scuti type pulsator with light variations of about 0.15 minutes. It has peculiar chemical abundances that are similar to those of Am star
s.
In 1900, it was discovered that this star had a variable radial velocity by William W. Campbell
and William H. Wright
using the Mills spectrograph at the Lick Observatory
. The 0.19377 day period of this variability as well as 0.2 magnitude changes in luminosity demonstrated in 1935 that the variability was intrinsic, rather than being the result of a spectroscopic binary. In 1938, a secondary period was discovered, and pulsation theory was proposed to model the variation. Since then, observation of Delta Scuti has shown that it pulsates in multiple discrete radial and non-radial modes. The strongest mode has a frequency of 59.731 μHz, the next strongest has a frequency of 61.936 μHz, and so forth, with a total of eight different frequency modes now modeled.
This star has two optical companions. The first is a +12.2 magnitude star located is 15.2 arcseconds from Delta Scuti. The second is a +9.2 magnitude star that is 53 arcseconds away.
Stellar classification
In astronomy, stellar classification is a classification of stars based on their spectral characteristics. The spectral class of a star is a designated class of a star describing the ionization of its chromosphere, what atomic excitations are most prominent in the light, giving an objective measure...
giant star
Giant star
A giant star is a star with substantially larger radius and luminosity than a main sequence star of the same surface temperature. Typically, giant stars have radii between 10 and 100 solar radii and luminosities between 10 and 1,000 times that of the Sun. Stars still more luminous than giants are...
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....
Scutum
Scutum
Scutum is a small constellation introduced in the seventeenth century. Its name is Latin for shield.-History:Scutum is the only constellation that owes its name to a non-classical historical figure...
. It is approximately 187 light years
Light Years
Light Years is the seventh studio album by Australian recording artist Kylie Minogue. It was released on 25 September 2000 by Parlophone and Mushroom Records. The album's style was indicative of her return to "mainstream pop dance tunes"....
from Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
. Delta Scuti is the prototype of the Delta Scuti type
Delta Scuti variable
A Delta Scuti variable is a variable star which exhibits variations in its luminosity due to both radial and non-radial pulsations of the star's surface. Typical brightness fluctuations are from 0.003 to 0.9 magnitudes in V over a period of a few hours, although the amplitude and period of the...
variable star
Variable star
A star is classified as variable if its apparent magnitude as seen from Earth changes over time, whether the changes are due to variations in the star's actual luminosity, or to variations in the amount of the star's light that is blocked from reaching Earth...
s. It is a high-amplitude δ Scuti type pulsator with light variations of about 0.15 minutes. It has peculiar chemical abundances that are similar to those of Am star
Am star
An Am star or metallic-line star is a type of chemically peculiar star of spectral type A whose spectrum has strong and often variable absorption lines of metals such as zinc, strontium, zirconium, and barium, and deficiencies of others, such as calcium and scandium...
s.
In 1900, it was discovered that this star had a variable radial velocity by William W. Campbell
William Wallace Campbell
William Wallace Campbell was an American astronomer, and director of Lick Observatory from 1900 to 1930. He specialized in spectroscopy.-Biography:...
and William H. Wright
William Hammond Wright
William Hammond Wright was an American astronomer. He was director of the Lick Observatory from 1935 until 1942....
using the Mills spectrograph at the Lick Observatory
Lick Observatory
The Lick Observatory is an astronomical observatory, owned and operated by the University of California. It is situated on the summit of Mount Hamilton, in the Diablo Range just east of San Jose, California, USA...
. The 0.19377 day period of this variability as well as 0.2 magnitude changes in luminosity demonstrated in 1935 that the variability was intrinsic, rather than being the result of a spectroscopic binary. In 1938, a secondary period was discovered, and pulsation theory was proposed to model the variation. Since then, observation of Delta Scuti has shown that it pulsates in multiple discrete radial and non-radial modes. The strongest mode has a frequency of 59.731 μHz, the next strongest has a frequency of 61.936 μHz, and so forth, with a total of eight different frequency modes now modeled.
This star has two optical companions. The first is a +12.2 magnitude star located is 15.2 arcseconds from Delta Scuti. The second is a +9.2 magnitude star that is 53 arcseconds away.