Zeta Puppis
Encyclopedia
Zeta Puppis is a star
in the constellation
of Puppis
. It is also known by the traditional names Naos (icon, from the Greek ναύς "ship") and Suhail Hadar (سهيل هدار, possibly "roaring bright one") in Arabic.
Its spectral class
is O5Ia, making it an exceptionally hot star, and it is one of the sky's few naked-eye class O-type stars. Its surface temperature is 42,400 K
, or about seven times hotter than the surface of the Sun
. Its mass is 40 solar mass
es.
Unlike many other stars at such great distance, the precise parameters for Zeta Puppis including its velocity are known, and can extrapolate back to the region where it was formed, a molecular cloud in Vela
. We can therefore derive a much more accurate distance than we can with, for example, Deneb
. 2008 reductions of Hipparcos raw data give a distance of 335 pc ± 4%, and for Deneb, 475 pc ± 20%.
Zeta Puppis is an extreme blue supergiant
, one of the brightest stars in the Milky Way
in terms of absolute magnitude
. Visually, it is 21,000 times more powerful than the Sun
, but being an extreme blue star most of its radiation
is in the ultraviolet
, and when this is considered it is approximately 360,000 solar. Blue stars are never very large, and Naos is no exception, being "merely" 11 times the solar radius. Red supergiants such as Betelgeuse
and Mu Cephei
are the largest stars.
For comparison, at the distance of Sirius
, Naos would cast strong shadows on Earth
, with a visible magnitude of -9 (near that of the quarter moon), but if it were placed at the center of our Solar System
, its intense heat at a distance of 1 AU
would heat the Earth to an incredible 6100 K, causing it to vaporize slowly and leaving a comet
-like trail. It would appear 20 times the Sun's diameter and shine 20,000 times brighter in the sky with an extremely powerful blue-white glow. Its apparent magnitude would be -37.5 and thus even scattered or refracted light would blind a human in seconds, even with a welding mask. In order for Naos to appear equal to the Sun's apparent magnitude of -26.8 combined with Earth-like temperatures, a planet would need to be 450 AU away from Naos, over eleven times the distance from the Sun to Pluto. The star is unlikely to harbor any planets at Earth like distances (1AU).
Zeta Puppis, being typical of O-type stars, is also notable for its extremely strong stellar wind
, and it has garnered increasing attention for this over the past decade. Its stellar wind velocity has been estimated at some 2300 km/s, which sees the star shed one millionth (
) of its solar mass each year, or about 10 million times that shed by our own Sun over a comparable time period. This mass ejection is highly evident in non-visible wavelengths such as radio
and X-ray
, and it has presented some excellent opportunities for study.
In several hundred thousand years, Naos will cool on its way to becoming a red supergiant and will pass through spectral classes B, A, F, G, K, and M as it cools. When this occurs, the star's output will mostly be in the visible spectrum, and Naos will appear from Earth as one of the brightest stars in the sky. Within 2 million years, Naos will turn into a Class M5 red supergiant bigger than the orbit of the Earth and it will eventually explode into a supernova
so powerful and bright that even at 970 light years it will appear much brighter than the full Moon
and could collapse into a black hole
. If so, the inwards ejected matter of the supernova will fall back into the black hole and form a powerful accretion disc with gamma rays ejected from the poles.
distant from the position as measured. However, data obtained in 2008 in a revision of Hipparcos data (see above) shows that the star was formed instead with the cluster Trumpler 10
and has been ejected from the cluster. This narrows the question of the age of Zeta Puppis, as Trumpler 10 has been measured to be 47 million years old. There is evidence of an ionization front (a "bow shock
") ahead of Naos. Howarth et al. in 1995 determined an anomalously high rotational velocity of 211 km/s at the equator, which also seems to be a common trend in O runaway stars, as well as an apparent enrichment in helium and nitrogen on the surface. Its estimated age is about 4 million
years.
if half-integers were used instead of whole integers. It was later found that these were due to ionized helium
.
was a United States Navy
Crater class cargo ship
named after the 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....
of Puppis
Puppis
Puppis is a constellation in the southern sky. Its name is the Latin word for the poop deck of a ship, and Puppis represents the deck of the ship and its deckhouses...
. It is also known by the traditional names Naos (icon, from the Greek ναύς "ship") and Suhail Hadar (سهيل هدار, possibly "roaring bright one") in Arabic.
Its spectral class
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...
is O5Ia, making it an exceptionally hot star, and it is one of the sky's few naked-eye class O-type stars. Its surface temperature is 42,400 K
Kelvin
The kelvin is a unit of measurement for temperature. It is one of the seven base units in the International System of Units and is assigned the unit symbol K. The Kelvin scale is an absolute, thermodynamic temperature scale using as its null point absolute zero, the temperature at which all...
, or about seven times hotter than the surface of the Sun
Sun
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...
. Its mass is 40 solar mass
Solar mass
The solar mass , , is a standard unit of mass in astronomy, used to indicate the masses of other stars and galaxies...
es.
Unlike many other stars at such great distance, the precise parameters for Zeta Puppis including its velocity are known, and can extrapolate back to the region where it was formed, a molecular cloud in Vela
Vela (constellation)
Vela is a constellation in the southern sky. Its name is Latin for the sails of a ship, and it was originally part of a larger constellation, the ship Argo Navis, which was later divided into three parts, the others being Carina and Puppis.-Stars:...
. We can therefore derive a much more accurate distance than we can with, for example, Deneb
Deneb
Deneb is the brightest star in the constellation Cygnus and one of the vertices of the Summer Triangle. It is the 19th brightest star in the night sky, with an apparent magnitude of 1.25. A blue-white supergiant, Deneb is also one of the most luminous nearby stars...
. 2008 reductions of Hipparcos raw data give a distance of 335 pc ± 4%, and for Deneb, 475 pc ± 20%.
Zeta Puppis is an extreme blue supergiant
Supergiant
Supergiants are among the most massive stars. They occupy the top region of the Hertzsprung-Russell diagram. In the Yerkes spectral classification, supergiants are class Ia or Ib . They typically have bolometric absolute magnitudes between -5 and -12...
, one of the brightest stars in the Milky Way
Milky Way
The Milky Way is the galaxy that contains the Solar System. This name derives from its appearance as a dim un-resolved "milky" glowing band arching across the night sky...
in terms of absolute magnitude
Absolute magnitude
Absolute magnitude is the measure of a celestial object's intrinsic brightness. it is also the apparent magnitude a star would have if it were 32.6 light years away from Earth...
. Visually, it is 21,000 times more powerful than the Sun
Sun
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...
, but being an extreme blue star most of its radiation
Electromagnetic radiation
Electromagnetic radiation is a form of energy that exhibits wave-like behavior as it travels through space...
is in the ultraviolet
Ultraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...
, and when this is considered it is approximately 360,000 solar. Blue stars are never very large, and Naos is no exception, being "merely" 11 times the solar radius. Red supergiants such as Betelgeuse
Betelgeuse
Betelgeuse, also known by its Bayer designation Alpha Orionis , is the eighth brightest star in the night sky and second brightest star in the constellation of Orion, outshining its neighbour Rigel only rarely...
and Mu Cephei
Mu Cephei
Mu Cephei , also known as Herschel's Garnet Star, is a red supergiant star in the constellation Cepheus. It is one of the largest and most luminous stars known in the Milky Way...
are the largest stars.
For comparison, at the distance of Sirius
Sirius
Sirius is the brightest star in the night sky. With a visual apparent magnitude of −1.46, it is almost twice as bright as Canopus, the next brightest star. The name "Sirius" is derived from the Ancient Greek: Seirios . The star has the Bayer designation Alpha Canis Majoris...
, Naos would cast strong shadows on 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...
, with a visible magnitude of -9 (near that of the quarter moon), but if it were placed at the center of our Solar System
Solar System
The Solar System consists of the Sun and the astronomical objects gravitationally bound in orbit around it, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The vast majority of the system's mass is in the Sun...
, its intense heat at a distance of 1 AU
Astronomical unit
An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....
would heat the Earth to an incredible 6100 K, causing it to vaporize slowly and leaving a comet
Comet
A comet is an icy small Solar System body that, when close enough to the Sun, displays a visible coma and sometimes also a tail. These phenomena are both due to the effects of solar radiation and the solar wind upon the nucleus of the comet...
-like trail. It would appear 20 times the Sun's diameter and shine 20,000 times brighter in the sky with an extremely powerful blue-white glow. Its apparent magnitude would be -37.5 and thus even scattered or refracted light would blind a human in seconds, even with a welding mask. In order for Naos to appear equal to the Sun's apparent magnitude of -26.8 combined with Earth-like temperatures, a planet would need to be 450 AU away from Naos, over eleven times the distance from the Sun to Pluto. The star is unlikely to harbor any planets at Earth like distances (1AU).
Zeta Puppis, being typical of O-type stars, is also notable for its extremely strong stellar wind
Stellar wind
A stellar wind is a flow of neutral or charged gas ejected from the upper atmosphere of a star. It is distinguished from the bipolar outflows characteristic of young stars by being less collimated, although stellar winds are not generally spherically symmetric.Different types of stars have...
, and it has garnered increasing attention for this over the past decade. Its stellar wind velocity has been estimated at some 2300 km/s, which sees the star shed one millionth (
) of its solar mass each year, or about 10 million times that shed by our own Sun over a comparable time period. This mass ejection is highly evident in non-visible wavelengths such as radioRadio waves
Radio waves are a type of electromagnetic radiation with wavelengths in the electromagnetic spectrum longer than infrared light. Radio waves have frequencies from 300 GHz to as low as 3 kHz, and corresponding wavelengths from 1 millimeter to 100 kilometers. Like all other electromagnetic waves,...
and X-ray
X-ray
X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...
, and it has presented some excellent opportunities for study.
In several hundred thousand years, Naos will cool on its way to becoming a red supergiant and will pass through spectral classes B, A, F, G, K, and M as it cools. When this occurs, the star's output will mostly be in the visible spectrum, and Naos will appear from Earth as one of the brightest stars in the sky. Within 2 million years, Naos will turn into a Class M5 red supergiant bigger than the orbit of the Earth and it will eventually explode into a supernova
Supernova
A supernova is a stellar explosion that is more energetic than a nova. It is pronounced with the plural supernovae or supernovas. Supernovae are extremely luminous and cause a burst of radiation that often briefly outshines an entire galaxy, before fading from view over several weeks or months...
so powerful and bright that even at 970 light years it will appear much brighter than the full 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...
and could collapse into a black hole
Black hole
A black hole is a region of spacetime from which nothing, not even light, can escape. The theory of general relativity predicts that a sufficiently compact mass will deform spacetime to form a black hole. Around a black hole there is a mathematically defined surface called an event horizon that...
. If so, the inwards ejected matter of the supernova will fall back into the black hole and form a powerful accretion disc with gamma rays ejected from the poles.
Origin
It was long thought that Zeta Puppis was formed in the Vela star-forming region, about 1400 light yearsLight 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"....
distant from the position as measured. However, data obtained in 2008 in a revision of Hipparcos data (see above) shows that the star was formed instead with the cluster Trumpler 10
Trumpler 10
Trumpler 10 is an open cluster located in the constellation Vela. It was possibly discovered by Nicolas Louis de Lacaille in 1751-52, as the cluster's location data matches well with No. II.6 in his catalog. The cluster was also officially discovered by James Dunlop in 1826 and rediscovered...
and has been ejected from the cluster. This narrows the question of the age of Zeta Puppis, as Trumpler 10 has been measured to be 47 million years old. There is evidence of an ionization front (a "bow shock
Bow shock
A bow shock is the area between a magnetosphere and an ambient medium. For stars, this is typically the boundary between their stellar wind and the interstellar medium....
") ahead of Naos. Howarth et al. in 1995 determined an anomalously high rotational velocity of 211 km/s at the equator, which also seems to be a common trend in O runaway stars, as well as an apparent enrichment in helium and nitrogen on the surface. Its estimated age is about 4 million
Million
One million or one thousand thousand, is the natural number following 999,999 and preceding 1,000,001. The word is derived from the early Italian millione , from mille, "thousand", plus the augmentative suffix -one.In scientific notation, it is written as or just 106...
years.
Helium
In 1896, Edward C. Pickering observed mysterious spectral lines from ζ Puppis, which fit the Rydberg formulaRydberg formula
The Rydberg formula is used in atomic physics to describe the wavelengths of spectral lines of many chemical elements. It was formulated by the Swedish physicist Johannes Rydberg, and presented on November 5, 1888.-History:...
if half-integers were used instead of whole integers. It was later found that these were due to ionized helium
Helium
Helium is the chemical element with atomic number 2 and an atomic weight of 4.002602, which is represented by the symbol He. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table...
.
Namesakes
USS Naos (AK-105)USS Naos (AK-105)
USS Naos was laid down as SS William R. Nelson under Maritime Commission contract by California Shipbuilding Corp., Los Angeles, California, 8 June 1943, named after Naos, the star in constellation Puppis. Naos was launched 30 June 1943 and sponsored by Miss Barbara Quarg...
was a United States Navy
United States Navy
The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...
Crater class cargo ship
Crater class cargo ship
Crater-class cargo ship is a category of freighter that was constructed for use by the United States Navy during World War II under Maritime Commission EC2-S-C1 type....
named after the star.