Delta Pavonis is a single
star
A star is a luminous spheroid of plasma (physics), plasma held together by Self-gravitation, self-gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night sk ...
[ in the southern ]constellation
A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object.
The first constellati ...
of Pavo. Its name is a Bayer designation
A Bayer designation is a stellar designation in which a specific star is identified by a Greek alphabet, Greek or Latin letter followed by the genitive case, genitive form of its parent constellation's Latin name. The original list of Bayer design ...
that is Latinized from δ Pavonis, and abbreviated Delta Pav or δ Pav. It has an apparent visual magnitude of 3.56,[ making it a fourth-magnitude star that is visible to the naked eye from the southern hemisphere. ]Parallax
Parallax is a displacement or difference in the apparent position of an object viewed along two different sightline, lines of sight and is measured by the angle or half-angle of inclination between those two lines. Due to perspective (graphica ...
measurements yield an estimated distance of from Earth
Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...
.[ This makes it one of the nearest bright stars to the Solar System. It is approaching the Sun with a radial velocity of −23.5 km/s, and is predicted to come as close as in around 49,200 years.][
]
Physical characteristics
This object is a subgiant
A subgiant is a star that is brighter than a normal main-sequence star of the same spectral class, but not as bright as giant stars. The term subgiant is applied both to a particular spectral luminosity class and to a stage in the evolution ...
of spectral type G8 IV; it will stop fusing hydrogen
Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter ...
at its core relatively soon, starting the process of becoming a red giant. Hence, Delta Pavonis is 24% brighter than the Sun, but the effective temperature
The effective temperature of a body such as a star or planet is the temperature of a black body that would emit the same total amount of electromagnetic radiation. Effective temperature is often used as an estimate of a body's surface temperature ...
of its outer atmosphere is less: 5,571 K.[ Its mass is 107% of Sun's mass,][ with a radius 120% of Sun's radius.][ Delta Pavonis's surface ]convection zone
A convection zone, convective zone or convective region of a star is a layer which is unstable due to convection. Energy is primarily or partially transported by convection in such a region. In a radiation zone, energy is transported by radiation ...
extends downward to about 43.1% of the star's radius, but only contains 4.8% of the star's mass.[
Spectroscopic examination of Delta Pavonis shows that it has a higher abundance of elements heavier than ]helium
Helium (from ) is a chemical element; it has chemical symbol, symbol He and atomic number 2. It is a colorless, odorless, non-toxic, inert gas, inert, monatomic gas and the first in the noble gas group in the periodic table. Its boiling point is ...
(metallicity
In astronomy, metallicity is the Abundance of the chemical elements, abundance of Chemical element, elements present in an object that are heavier than hydrogen and helium. Most of the normal currently detectable (i.e. non-Dark matter, dark) matt ...
) than does the Sun. This value is typically given in terms of the ratio of iron
Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's o ...
(chemical symbol Fe) to hydrogen (H) in a star's atmosphere, relative to that in Sun's atmosphere (iron being a good proxy for the presence of other heavy elements). The metallicity of Delta Pavonis is approximately
This notation gives the logarithm
In mathematics, the logarithm of a number is the exponent by which another fixed value, the base, must be raised to produce that number. For example, the logarithm of to base is , because is to the rd power: . More generally, if , the ...
of the iron-to-hydrogen ratio, relative to that of the Sun, meaning that Delta Pavonis's iron abundance is 235% of that of Sun.[ It is considered super metal-rich, and the high metallicity has slowed its ]evolution
Evolution is the change in the heritable Phenotypic trait, characteristics of biological populations over successive generations. It occurs when evolutionary processes such as natural selection and genetic drift act on genetic variation, re ...
.[ Studies have shown a correlation between abundant heavy elements in stars, and the presence of a planetary system,][ so Delta Pavonis has a greater than average probability of harboring planets.][
The age of Delta Pavonis is approximately 6.1 billion years.][ It appears to be rotating slowly, with a ]projected rotational velocity
Stellar rotation is the angular motion of a star about its axis. The rate of rotation can be measured from the spectrum of the star, or by timing the movements of active features on the surface.
The rotation of a star produces an equatorial bu ...
of 0.32 kilometers per second.[
]
Possible planetary system
The existence of a Jupiter-mass gas giant on a long-period orbit around Delta Pavonis is suspected, as of 2021, based on astrometric
Astrometry is a branch of astronomy that involves precise measurements of the positions and movements of stars and other celestial bodies. It provides the kinematics and physical origin of the Solar System and this galaxy, the Milky Way.
History ...
data.
SETI
Delta Pavonis has been identified by Maggie Turnbull and Jill Tarter of the SETI Institute
The SETI Institute is a not-for-profit research organization incorporated in 1984 whose mission is to explore, understand, and explain the origin and nature of life in the universe, and to use this knowledge to inspire and guide present and futu ...
as the "Best SETI
Seti or SETI may refer to:
Astrobiology
* SETI, the search for extraterrestrial intelligence.
** SETI Institute, an astronomical research organization
*** SETIcon, a former convention organized by the SETI Institute
** Berkeley SETI Research Cent ...
target" among the 100 closest G-type stars. Properties in its favor include a high metallicity, minimal level of magnetic activity
A stellar magnetic field is a magnetic field generated by the motion of conductive Plasma (physics), plasma inside a star. This motion is created through convection, which is a form of energy transport involving the physical movement of material ...
, low rotation rate, and kinematic membership in the thin disk population of the Milky Way
The Milky Way or Milky Way Galaxy is the galaxy that includes the Solar System, with the name describing the #Appearance, galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars in other arms of the galax ...
. Gas giant
A gas giant is a giant planet composed mainly of hydrogen and helium. Jupiter and Saturn are the gas giants of the Solar System. The term "gas giant" was originally synonymous with "giant planet". However, in the 1990s, it became known that Uranu ...
s orbiting in, near, or through a star's habitable zone
In astronomy and astrobiology, the habitable zone (HZ), or more precisely the circumstellar habitable zone (CHZ), is the range of orbits around a star within which a planetary surface can support liquid water given sufficient atmospheric pressu ...
may destabilize the orbits of terrestrial planets in that zone; the lack of detected radial velocity variation suggests that there are no such gas giants orbiting Delta Pavonis. However, observation has detected no artificial radio sources.[ Delta Pavonis, a close photometric match to the Sun, is the nearest solar analog that is not a member of a binary or multiple ]star system
A star system or stellar system is a small number of stars that orbit each other, bound by gravity, gravitational attraction. It may sometimes be used to refer to a single star. A large group of stars bound by gravitation is generally calle ...
.[
]
See also
* List of nearest G-type stars
References
Further reading
*
*
*
External links
*
{{DEFAULTSORT:Delta Pavonis
G-type subgiants
Pavonis, Delta
Suspected variables
Hypothetical planetary systems
Pavo (constellation)
J20084376-6610563
Pavonis, Delta
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CD-66 2367
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