Stars A curved line of stars comprising Alpha,
Kappa,
Mu,
Beta,
Nu and
Gamma Phoenicis was seen as a boat by the ancient Arabs. French explorer and astronomer
Nicolas Louis de Lacaille charted and designated 27 stars with the
Bayer designations Alpha through to Omega in 1756. Of these, he labelled two stars close together Lambda, and assigned Omicron, Psi and Omega to three stars, which subsequent astronomers such as
Benjamin Gould felt were too dim to warrant their letters. A different star was subsequently labelled Psi Phoenicis, while the other two designations fell out of use. Ankaa is the brightest star in the constellation. It is an orange giant of
apparent visual magnitude 2.37 and
spectral type K0.5IIIb, 77 light years distant from Earth and orbited by a secondary object about which little is known. Lying close by Ankaa is
Kappa Phoenicis, a
main sequence star of spectral type A5IVn and apparent magnitude 3.90. Located centrally in the asterism,
Beta Phoenicis is the second brightest star in the constellation and another
binary star. Together the stars, both yellow giants of spectral type G8, shine with an apparent magnitude of 3.31, though the components are of individual apparent magnitudes of 4.0 and 4.1 and orbit each other every 168 years.
Zeta Phoenicis or
Wurren is an
Algol-type
eclipsing binary, with an
apparent magnitude fluctuating between 3.9 and 4.4 with a period of around 1.7 days (40 hours); its dimming results from the component two blue-white B-type stars, which orbit and block out each other from Earth. The two stars are 0.05 AU from each other, while a third star is around 600 AU away from the pair, and has an orbital period exceeding 5000 years. The system is around 300 light years distant. In 1976, researchers Clausen, Gyldenkerne, and Grønbech calculated that a nearby 8th magnitude star is a fourth member of the system. AI Phe is an eclipsing binary star identified in 1972. Its long mutual eclipses and combination of spectroscopic and astrometric data allows precise measurement of the masses and radii of the stars which is viewed as a potential cross-check on stellar properties and distances independent on Ceiphid Variables and such techniques. The long eclipse events require space-based observations to avoid Solar interference. Gamma Phoenicis is a
red giant of spectral type M0IIIa and varies between magnitudes 3.39 and 3.49. It lies 235 light years away.
Psi Phoenicis is another red giant, this time of spectral type M4III, and has an apparent magnitude that ranges between 4.3 and 4.5 over a period of around 30 days. Lying 340 light years away,
W Phoenicis is a
Mira variable, ranging from magnitude 8.1 to 14.4 over 333.95 days. A red giant, its spectrum ranges between M5e and M6e. Located 6.5 degrees west of Ankaa is
SX Phoenicis, a variable star which ranges from magnitude 7.1 to 7.5 over a period of a mere 79 minutes. Its spectral type varies between A2 and F4. It gives its name to a group of stars known as
SX Phoenicis variables.
Rho and
BD Phoenicis are
Delta Scuti variables—short period (six hours at most) pulsating stars that have been used as
standard candles and as subjects to study
astroseismology. Rho is spectral type F2III, and ranges between magnitudes 5.20 and 5.26 over a period of 2.85 hours. BD is of spectral type A1V, and ranges between magnitudes 5.90 and 5.94.
Nu Phoenicis is a yellow-white main sequence star of spectral type F9V and magnitude 4.96. Lying some 49 light years distant, it is around 1.2 times as massive as the Sun, and likely to be surrounded by a disk of dust. It is the closest star in the constellation that is visible with the unaided eye. White dwarfs are extremely dense stars compacted into a volume the size of the Earth. With around 85% of the mass of the Sun, Gliese 915 has a
surface gravity of 108.39 ± 0.01 (2.45 · 108)
cm·
s−2, or approximately 250,000 of
Earth's. Ten stars have been found to have planets to date, and four planetary systems have been discovered with the
SuperWASP project.
HD 142 is a yellow giant that has an apparent magnitude of 5.7, and has a planet (
HD 142 b) 1.36 times the mass of Jupiter which orbits every 328 days.
HD 2039 is a yellow subgiant with an apparent magnitude of 9.0 around 330 light years away which has a planet (
HD 2039 b) six times the mass of Jupiter.
WASP-18 is a star of magnitude 9.29 which was discovered to have a hot Jupiter-like planet (
WASP-18b) taking less than a day to orbit the star. The planet is suspected to be causing WASP-18 to appear older than it really is.
WASP-4 and
WASP-5 are solar-type yellow stars around 1000 light years distant and of 13th magnitude, each with a single planet larger than Jupiter.
WASP-29 is an orange dwarf of spectral type K4V and visual magnitude 11.3, which has a planetary companion of similar size and mass to Saturn. The planet completes an orbit every 3.9 days.
WISE J003231.09-494651.4 and
WISE J001505.87-461517.6 are two
brown dwarfs discovered by the
Wide-field Infrared Survey Explorer, and are 63 and 49 light years away respectively. Initially hypothesised before they were belatedly discovered, brown dwarfs are objects more massive than planets, but which are of insufficient mass for
hydrogen fusion characteristic of stars to occur. Many are being found by sky surveys. Phoenix contains
HE0107-5240, possibly one of the oldest stars yet discovered. It has around 1/200,000 the
metallicity that the Sun has and hence must have formed very early in the history of the universe. With a visual magnitude of 15.17, it is around 10,000 times dimmer than the faintest stars visible to the naked eye and is 36,000 light years distant.
Robert's Quartet (composed of the irregular galaxy
NGC 87, and three spiral galaxies
NGC 88,
NGC 89 and
NGC 92) is a group of four galaxies located around 160 million light-years away which are in the process of colliding and merging. They are within a circle of radius of 1.6 arcmin, corresponding to about 75,000 light-years. Located in the galaxy ESO 243-49 is
HLX-1, an
intermediate-mass black hole—the first one of its kind identified. It is hypothesized to be a remnant of a dwarf galaxy that was absorbed in a
collision with ESO 243-49. Before its discovery, this class of black hole was only hypothesized. Lying within the bounds of the constellation is the gigantic
Phoenix Cluster, which is around 7.3 million light years wide and 5.7 billion light years away, making it one of the most massive
galaxy clusters. It was first discovered in 2010, and the central galaxy is producing an estimated 740 new stars a year. Larger still is
El Gordo, or officially ACT-CL J0102-4915, whose discovery was announced in 2012. Located around 7.2 billion light years away, it is composed of two subclusters in the process of colliding, resulting in the spewing out of hot gas, seen in X-rays and infrared images.
Meteor showers Phoenix is the
radiant of two annual
meteor showers. The
Phoenicids, also known as the December Phoenicids, were first observed on 3 December 1887. The shower was particularly intense in December 1956, and is thought related to the breakup of the
short-period comet 289P/Blanpain. It peaks around 4–5 December, though is not seen every year. A very minor meteor shower peaks around July 14 with around one meteor an hour, though meteors can be seen anytime from July 3 to 18; this shower is referred to as the July Phoenicids. ==See also==