Delta Pavonis

Location of δ Pavonis (circled)
Observation data Epoch J2000       Equinox J2000
Constellation	Pavo
Right ascension	20h 08m 43.60887s [1]
Declination	−66° 10′ 55.4428″ [1]
Apparent magnitude (V)	3.56 [2]
Characteristics
Spectral type	G8 IV [3]
U−B color index	0.45 [2]
B−V color index	0.76 [2]
Variable type	Suspected [4]
Astrometry
Radial velocity (Rv)	−23.52±0.81 [5] km/s
Proper motion (μ)	RA: +1,211.761  mas/ yr [1] Dec.: –1,130.237  mas/ yr [1]
Parallax (π)	163.9544 ± 0.1222  mas [1]
Distance	19.89 ± 0.01  ly (6.099 ± 0.005  pc)
Absolute magnitude (MV)	4.62 [6]
Details [7]
Mass	1.051±0.062 [8]  M☉
Radius	1.197±0.016  R☉
Luminosity	1.24±0.03  L☉
Surface gravity (log g)	4.26±0.06  cgs
Temperature	5,571±48  K
Metallicity [Fe/H]	0.33±0.03  dex
Rotation	21.4±9.3  d [9]
Rotational velocity (v sin i)	0.32 km/s
Age	6.6–6.9 [10] Gyr 9.3 [6]  Gyr
Other designations
δ Pav, NSV 12790, CD−66 2367, GJ 780, HD 190248, HIP 99240, HR 7665, SAO 254733, LFT 1520, LHS 485, LTT 7946, 2MASS J20084376-6610563 [11]
Database references
SIMBAD	data

Delta Pavonis, Latinized from δ Pavonis, is a single ^[12] star in the southern constellation of Pavo. It has an apparent visual magnitude of 3.56, ^[11] making it a fourth-magnitude star that is visible to the naked eye from the southern hemisphere. Parallax measurements yield an estimated distance of 19.89 light-years (6.10 parsecs) from Earth. ^[1] 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 17.8 light-years in around 49,200 years. ^[5]

Observations

This object is a subgiant of spectral type G8 IV; it will stop fusing hydrogen 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 of its outer atmosphere is less: 5,571 K. ^[7] Its mass is 105% of Sol's mass, with a mean radius 120% of Sol's radius. Delta Pavonis's surface convection zone extends downward to about 43.1% of the star's radius, but only contains 4.8% of the star's mass. ^[13]

Spectroscopic examination of Delta Pavonis shows that it has a higher abundance of elements heavier than helium ( metallicity) than does the Sun. This value is typically given in terms of the ratio of iron (chemical symbol Fe) to hydrogen (H) in a star's atmosphere, relative to that in Sol's atmosphere (iron being a good proxy for the presence of other heavy elements). The metallicity of Delta Pavonis is approximately

${\displaystyle {\begin{smallmatrix}\left[{\frac {Fe}{H}}\right]\ =\ 0.33\end{smallmatrix}}}$

This notation gives the logarithm of the iron-to-hydrogen ratio, relative to that of the Sun, meaning that Delta Pavonis's iron abundance is 214% of that of Sol. It is considered super metal-rich, and the high metallicity has slowed its evolution. ^[14] Studies have shown a correlation between abundant heavy elements in stars, and the presence of a planetary system, ^[15] so Delta Pavonis has a greater than average probability of harboring planets. ^[14]

The age of Delta Pavonis is approximately 6.6 to 6.9 billion years, ^[10] and is certainly in the 5 to 7 billion year range. ^[14] It appears to be rotating slowly, with a projected rotational velocity of 0.32 kilometers per second. ^[7]

Search for planets

The existence of a Jupiter-mass gas giant on a long-period orbit around Delta Pavonis is suspected, as of 2021, based on astrometric data. ^[16] A study in 2023 detected a trend in the star's radial velocity, which may indicate the presence of a planetary companion, supporting the previous astrometric result. Such a planet would, at minimum, orbit with a period of 37 years at a distance of 11.1  AU, and have a mass at least 69  M_🜨 (0.22  M_J). ^[9]

SETI

Delta Pavonis has been identified by Maggie Turnbull and Jill Tarter of the SETI Institute as the "Best SETI target" among the 100 closest G-type stars. Properties in its favor include a high metallicity, minimal level of magnetic activity, low rotation rate, and kinematic membership in the thin disk population of the Milky Way. Gas giants orbiting in, near, or through a star's habitable zone 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. ^[17] 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. ^[14]

References

Further reading

External links

• "Delta Pavonis". SolStation. Retrieved November 3, 2005.