Chi Cygni
Encyclopedia
Chi Cygni is a variable star
of the Mira
type in the constellation Cygnus
.
Chi Cygni shows one of the largest variations in magnitude
known. Typically it brightens and fades from 5th to 13th magnitude. The average period of this brightness fluctuation is 407 days. Observed extremes were 3.3 and 14.3 respectively. Thus Chi Cygni is visible at its minimum only with telescope
s larger than 30 centimeters, while at maximum brightness is easily visible to the naked eye. Its distance is approximately 345 light years.
The astronomer Gottfried Kirch
discovered its variability in 1686.
Thomas Dick
, LL.D, writes:
"The period of this star has been settled by Maraldi and Cassini at 405 days; but from a mean of the observations of Mr. Pigot, it appears to be only 392, or at most 396-7/8 days.
"The particulars relating to it are,
"It is situated in the neck [of the Swan constellation], and nearly equi-distant from Beta and Gamma, and south by west from Deneb, at the distance of about twelve degrees, and is marked Chi."
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...
of the Mira
Mira variable
Mira variables , named after the star Mira, are a class of pulsating variable stars characterized by very red colors, pulsation periods longer than 100 days, and light amplitudes greater than one magnitude in infrared and 2.5 magnitude in visual...
type in the constellation Cygnus
Cygnus (constellation)
Cygnus is a northern constellation lying on the plane of the Milky Way. Its name is the Latinized Hellenic word for swan. One of the most recognizable constellations of the northern summer and autumn, it features a prominent asterism known as the Northern Cross...
.
Chi Cygni shows one of the largest variations in magnitude
Apparent magnitude
The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...
known. Typically it brightens and fades from 5th to 13th magnitude. The average period of this brightness fluctuation is 407 days. Observed extremes were 3.3 and 14.3 respectively. Thus Chi Cygni is visible at its minimum only with telescope
Telescope
A telescope is an instrument that aids in the observation of remote objects by collecting electromagnetic radiation . The first known practical telescopes were invented in the Netherlands at the beginning of the 1600s , using glass lenses...
s larger than 30 centimeters, while at maximum brightness is easily visible to the naked eye. Its distance is approximately 345 light years.
The astronomer Gottfried Kirch
Gottfried Kirch
Gottfried Kirch was a German astronomer. The son of a shoemaker in Guben, Electorate of Saxony, Kirch first worked as a calendar-maker in Saxonia and Franconia. He began to learn astronomy in Jena, and studied under Hevelius in Danzig...
discovered its variability in 1686.
Thomas Dick
Thomas Dick
Reverend Thomas Dick , was a Scottish church minister, science teacher and writer, known for his works on astronomy and practical philosophy, combining science and Christianity, and defusing the tension between the two.-Early life:Thomas was brought up in the strict tenets of the presbyterian...
, LL.D, writes:
"The period of this star has been settled by Maraldi and Cassini at 405 days; but from a mean of the observations of Mr. Pigot, it appears to be only 392, or at most 396-7/8 days.
"The particulars relating to it are,
- When at its full brightness, it undergoes no perceptible change for a fortnight.
- It is about three and a half months in increasing from the eleventh magnitude to its full brightness, and the same in decreasing; for which reason it may be considered as invisible during six months.
- It does not always attain the same degree of lustre, being sometimes of the 5th and sometimes of the seventh magnitude.
"It is situated in the neck [of the Swan constellation], and nearly equi-distant from Beta and Gamma, and south by west from Deneb, at the distance of about twelve degrees, and is marked Chi."