18 Aquarii

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18 Aquarii
Observation data
Epoch J2000       Equinox J2000
Constellation Aquarius
Right ascension 21h 24m 11.49206s [1]
Declination −12° 52 41.1928 [1]
Apparent magnitude  (V)5.49 [2]
Characteristics
Spectral type F0 V [3]
B−V color index +0.29 [2]
Astrometry
Radial velocity (Rv)−3.0±6.9 [4]  km/s
Proper motion (μ)RA: +89.60 [1]   mas/yr
Dec.: +8.62 [1]   mas/yr
Parallax (π)21.23 ± 0.29  mas
Distance 154 ± 2  ly
(47.1 ± 0.6  pc)
Absolute magnitude  (MV)2.12 [4]
Details
Mass 1.54 [5]   M
Luminosity 11.8 [4]   L
Surface gravity (log g)3.98 [6]   cgs
Temperature 7,194 [6]   K
Metallicity [Fe/H]–0.16 [6]   dex
Rotational velocity (v sin i)138 [7]  km/s
Age 480 [5]   Myr
Other designations
18 Aqr, BD−13° 5923, FK5  1562, HD  203705, HIP  105668, HR  8187, SAO  164364 [8]
Database references
SIMBAD data

18 Aquarii is a single, [9] yellow-white hued star in the equatorial constellation of Aquarius. The designation is from the catalogue of English astronomer John Flamsteed, first published in 1712. The star is faintly visible to the naked eye with an apparent visual magnitude of 5.49 [2] and is located about 154 light-years (47 parsecs ) from Earth. [1]

This is an F-type main sequence star with a stellar classification of F0 V. [3] It is an estimated 480 [5]  million years old and has a high rate of spin with a projected rotational velocity of 138 km/s. [7] The star has 1.54 [5] times the mass of the Sun and is radiating 11.8 [4] times the Sun's luminosity from its photosphere at an effective temperature of 7,194 K. [6]

Related Research Articles

<span class="mw-page-title-main">Delta Aquarii</span> Star in the constellation Aquarius

Delta Aquarii, officially named Skat, is the third-brightest star in the constellation of Aquarius. The apparent visual magnitude is 3.3, which can be seen with the naked eye. The distance to this star is about 113 light-years based upon parallax measurements, and it has a close companion.

Chi<sup>1</sup> Sagittarii Star in the constellation Sagittarius

Chi1 Sagittarii (χ1 Sagittarii) is a binary star system in the zodiac constellation of Sagittarius. The pair have a combined apparent visual magnitude of +5.03, which is bright enough to be seen with the naked eye. Based upon an annual parallax shift of 12.95 mas as seen from Earth, it is located around 252 light years from the Sun. It is advancing through space in the general direction of the Earth with a radial velocity of −43.4 km/s.

Delta Sextantis is a solitary star in the equatorial constellation of Sextans. With an annual parallax shift of 10.13 mas, it lies at a distance of around 322 light years from the Sun. This star is faintly visible to the naked eye, having an apparent visual magnitude of +5.25. According to the Bortle scale, that means it can be viewed from dark suburban skies.

<span class="mw-page-title-main">Tau Virginis</span> Star in the constellation Virgo

Tau Virginis is a single star in the zodiac constellation Virgo. With an apparent visual magnitude of 4.28, it is faintly visible to the naked eye. The distance to Tau Virginis, based upon parallax measurements, is approximately 225 light years with a margin of error of ±3 light years.

Psi<sup>3</sup> Aquarii Binary star in the constellation Aquarius

Psi3 Aquarii, Latinized from ψ3 Aquarii, is the Bayer designation for a visual binary star system in the constellation of Aquarius. It has an apparent visual magnitude of 4.98, which is bright enough to be seen with the naked eye. Parallax measurements give a distance estimate of roughly 262 light-years.

<span class="mw-page-title-main">101 Aquarii</span> Star in the constellation Aquarius

101 Aquarii is a star in the equatorial constellation of Aquarius. 101 Aquarii is the Flamsteed designation, although it also bears the Bayer designation b3 Aquarii. The combined apparent visual magnitude of the pair is 4.71, which is bright enough to be seen with the naked eye from the suburbs. The distance of this star from Earth is estimated as 290 light-years based upon parallax measurements.

97 Aquarii is a binary star system in the equatorial constellation of Aquarius. 97 Aquarii is the Flamsteed designation. The combined apparent visual magnitude of the system is 5.20; the brighter star is magnitude 5.59 while the companion is magnitude 6.72. Based upon an annual parallax shift of 15.30 milliarcseconds, this system is at a distance of around 210 light-years from Earth.

107 Aquarii is a double star in the equatorial constellation of Aquarius. 107 Aquarii is the Flamsteed designation, although it also bears the Bayer designation i2 Aquarii. The pair have an angular separation of 6.787 arcseconds. They have a combined apparent visual magnitude of +5.305, with individual magnitudes of 5.72 and 6.72. The annual parallax shift measured for the two components is 16.1 mas and 20.0 mas respectively, although with significant statistical margins of error and flags for potential unreliability of both values. This indicates the system may be at a distance of 160–200 light-years from Earth.

51 Aquarii is a binary star system located around 410 light years away from the Sun in the equatorial constellation of Aquarius. 51 Aquarii is its Flamsteed designation. It is visible to the naked eye as a dim, yellow-white hued star with a combined apparent visual magnitude of 5.78. The system is moving further from the Earth with a heliocentric radial velocity of +6 km/s.

39 Aquarii is a star in the zodiac constellation of Aquarius. 39 Aquarii is its Flamsteed designation. It is a faint naked eye star with an apparent visual magnitude of 6.03. Based upon an annual parallax shift of 23.78 measured with a 3% margin of error, this star is at a distance of around 137 light-years from Earth. It is a double star with a magnitude 9.3 companion at an angular separation of 0.6 arcseconds along a position angle of 257°.

Omega<sup>2</sup> Aquarii Star in the constellation Aquarius

Omega2 Aquarii, Latinised from ω2 Aquarii, is the Bayer designation for a triple star system in the equatorial constellation of Aquarius. It can be seen with the naked eye, having an apparent visual magnitude of 4.49. The approximate distance to this star, 149 light-years, is known from parallax measurements taken during the Hipparcos mission.

<span class="mw-page-title-main">Tau Centauri</span> White-hued star in the constellation Centaurus

Tau Centauri, Latinized from τ Centauri, is a solitary star in the southern constellation of Centaurus. It is visible to the naked eye with an apparent visual magnitude of +3.86. The distance to this star, based upon an annual parallax shift of 24.85 mas, is 131 light years. There is a 98% chance that it is a co-moving companion of Gamma Centauri; the two stars have an estimated separation of 1.7 ly (0.53 pc).

δ Doradus is a star in the southern constellation of Dorado. Based upon an annual parallax shift of 21.80 mas as seen from Earth, it is located around 150 light years from the Sun. The star is visible to the naked eye with an apparent visual magnitude of +4.34.

<span class="mw-page-title-main">54 Ceti</span> Star in the constellation Aries

54 Ceti is an older Flamsteed designation for a star that is now located within the constellation boundaries of Aries, the Ram. In the present day it is known by star catalogue identifiers like HD 11257 or HR 534. At an apparent visual magnitude of 5.94, it can be seen with the naked eye. The distance to this star, as determined using parallax measurements made during the Hipparcos mission, is approximately 139 light-years, give or take a 6 light-year margin of error. It is located near the ecliptic and hence is subject to occasional occultation by the Moon.

HD 118889 is a binary star system in the northern constellation of Boötes. It is faintly visible to the naked eye as a point of light with an apparent visual magnitude of 5.57. The system is located at a distance of approximately 196 light years from the Sun based on stellar parallax, but is drifting closer with a radial velocity of −26 km/s.

<span class="mw-page-title-main">HD 211575</span> Star in the constellation Aquarius

HD 211575 is a star in the constellation Aquarius in between "Gamma Aquarii", "Pi Aquarii" and "Sadalmelik". It is a member of the corona of the Ursa Major moving group.

<span class="mw-page-title-main">Gamma Crateris</span> Star in the constellation Crater

Gamma Crateris is a binary star system, divisible with a small amateur telescope, and located at the center of the southern constellation of Crater. It is visible to the naked eye with an apparent visual magnitude of 4.06. With an annual parallax shift of 39.62 mas as seen from Earth, this star is located 82.3 light years from the Sun. Based upon the motion of this system through space, it is a potential member of the Castor Moving Group.

2 Ceti is a single star in the equatorial constellation of Cetus, near the border with Aquarius. It is visible to the naked eye with an apparent visual magnitude of 4.483. The distance to 2 Ceti can be estimated from its annual parallax shift of 12.0 mas, which yields a value of around 272 light years. It appears to be moving further from the Earth with a heliocentric radial velocity of about +8 km/s.

<span class="mw-page-title-main">64 Eridani</span> Single, yellow-white hued star in the constellation Eridanus

64 Eridani is a single, yellow-white hued star in the constellation Eridanus having variable star designation S Eridani. It is faintly visible to the naked eye with an apparent visual magnitude of 4.77. The annual parallax shift is measured at 12.01 mas, which equates to a distance of about 272 light years. In addition to its proper motion, it is moving closer to the Sun with a radial velocity of around −9 km/s.

Nu2 Lyrae, Latinized from ν2 Lyrae, or sometimes simply Nu Lyrae, is a solitary star in the northern constellation of Lyra. Based upon an annual parallax shift of 14.09 mas as seen from Earth, it is located around 231 light years from the Sun. With an apparent visual magnitude of 5.23, it is bright enough to be faintly visible to the naked eye.

References

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