Eta Cygni

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η Cygni
Cygnus constellation map.svg
Red circle.svg
Location of η Cygni (circled)
Observation data
Epoch J2000.0        Equinox J2000.0 (ICRS)
Constellation Cygnus
Right ascension 19h 56m 18.37184s [1]
Declination +35° 05′ 00.3224″ [1]
Apparent magnitude  (V)3.889 [2]
Characteristics
Spectral type K0 III [3]
U−B color index +0.881 [2]
B−V color index +1.035 [2]
Astrometry
Radial velocity (Rv)−26.57±0.34 [1]  km/s
Proper motion (μ)RA: −34.165  mas/yr [1]
Dec.: −28.393  mas/yr [1]
Parallax (π)23.5482 ± 0.1078  mas [1]
Distance 138.5 ± 0.6  ly
(42.5 ± 0.2  pc)
Absolute magnitude  (MV)0.74 [4]
Details
Mass 0.9±0.1 [5]   M☉
Radius 10.2±0.3 [5]   R☉
Luminosity 60 [5]   L☉
Surface gravity (log g)2.36±0.08 [5]   cgs
Temperature 4,783±20 [6]   K
Metallicity [Fe/H]−0.02 [5]   dex
Rotational velocity (v sin i)2.2 [7]  km/s
Other designations
η Cygni, 21 Cygni, BD+34 3798, HD  188947, HIP  98110, HR  7615, SAO  69116, TYC  2677-1816-1, IRAS 19544+3456 [8]
Database references
SIMBAD data

Eta Cygni (η Cygni) is a star in the northern constellation of Cygnus. It is visible to the naked eye with an apparent visual magnitude of 3.889. [2] The star lies along the main body of the constellation, about midway between Gamma Cygni and Albireo. [9] Based upon an annual parallax shift of 23.55  mas, [1] it is located 138.5  light years from the Sun.

This is an evolved red clump [10] giant star with a stellar classification of K0 III. [3] It is presently on the horizontal branch and is generating energy through the nuclear fusion of helium at its core. The star has about 0.9 times the mass of the Sun and has expanded to 10 It radiates 60 times the solar luminosity from its outer atmosphere at an effective temperature of 4,780 K. [5]

Eta Cygni has five visual companions, [11] of which only component B appears to be physically associated. This magnitude 12.0 star lies at an angular separation of 7.80  arc seconds along a position angle of 206°, as of 2007. [12]

Related Research Articles

<span class="mw-page-title-main">Nu Aurigae</span> Variable star in the constellation Auriga

Nu Aurigae, Latinised from ν Aurigae, is the Bayer designation for a star in the northern constellation of Auriga. It is visible to the naked eye with an apparent visual magnitude of 3.96 and is approximately 200 light-years distant from the Earth. This is an evolved giant star with a stellar classification of G9.5 III. It is a red clump star, which indicates that it is generating energy through the fusion of helium at its core. The outer envelope has expanded to 18 times the radius of the Sun and cooled to 4,576 K, giving it the characteristic yellow-hued glow of a G-type star. It shines with 126 times the luminosity of the Sun.

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

Eta Ceti is a star in the equatorial constellation of Cetus. It has the traditional name Deneb Algenubi or Algenudi. The apparent visual magnitude of this star is +3.4, making it the fourth-brightest star in this otherwise relatively faint constellation. The distance to this star can be measured directly using the parallax technique, yielding a value of 120.5 light-years.

<span class="mw-page-title-main">Tau Cassiopeiae</span> K-type giant star in the constellation Cassiopeia

Tau Cassiopeiae is a solitary, orange hued star in the northern constellation of Cassiopeia. It is bright enough to be seen with the naked eye, having an apparent visual magnitude of +4.86. Based upon an annual parallax shift of 18.75 mas as seen from Earth, this system is located about 174 light years from the Sun.

<span class="mw-page-title-main">Delta Crateris</span> K-type giant star in the constellation Crater

Delta Crateris is a solitary star in the southern constellation of Crater. With an apparent visual magnitude of 3.56, it is the brightest star in this rather dim constellation. It has an annual parallax shift of 17.017 mas as measured from Earth, indicating Delta Crateris lies at a distance of 192 ly from the Sun.

HD 173780 is a single star in the northern constellation Lyra, near the southern constellation border with Hercules. It is an orange-hued star that is faintly visible to the naked eye with an apparent visual magnitude of +4.84. This object is located at a distance of approximately 237 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −17 km/s.

<span class="mw-page-title-main">Zeta Cygni</span> Star in the constellation Cygnus

Zeta Cygni is a binary star system in the northern constellation of Cygnus, the swan. It has an apparent visual magnitude of 3.26 and, based upon parallax measurements, is about 143 light-years away.

39 Cygni is a binary star system near the southern border of the northern constellation of Cygnus, approximately 270 light years away from Earth. It is visible to the naked eye as an orange-hued star with an apparent visual magnitude of 4.43. The system is moving closer to the Sun with a heliocentric radial velocity of −15 km/s.

<span class="mw-page-title-main">52 Cygni</span> Binary star system in the constellation Cygnus

52 Cygni is a giant star in the northern constellation of Cygnus with an apparent magnitude of 4.22. Based on its Hipparcos parallax, it is about 291 light-years (89 pc) away.

4 Vulpeculae is a single, orange-hued star in the northern constellation of Vulpecula. It forms part of the asterism, formerly thought to be an open cluster, called the coathanger or Brocchi's Cluster. The star is faintly visible to the naked eye with an apparent visual magnitude of 5.16. The distance to this star, based upon an annual parallax shift of 12.5320±0.1008 mas, is around 260 light years.

27 Hydrae is a triple star system system in the equatorial constellation of Hydra, located 222 light years away from the Sun. It is visible to the naked eye as a faint, orange-hued star with a combined apparent visual magnitude of 4.82. The system is moving further from the Earth with a heliocentric radial velocity of +25.6 km/s.

<span class="mw-page-title-main">Theta Librae</span> Star in the constellation Libra

θ Librae, Latinised as Theta Librae, is a single star in the southern zodiac constellation of Libra, near the constellation border with Scorpius. It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.14. The distance to this star is approximately 168 light years, as determined by parallax, and it is drifting further away with a radial velocity of 5 km/s. The position of this star near the ecliptic means it is subject to lunar occultations.

<span class="mw-page-title-main">1 Serpentis</span> Red giant star in the constellation Virgo

1 Serpentis is a red giant in the constellation Virgo with an apparent magnitude of 5.5. It is a red clump giant, a cool horizontal branch star that is fusing helium in its core. It has expanded to over 13 times the radius of the Sun and although it is cooler at 4,581 K it is 77 times more luminous. It is 322 light years away.

<span class="mw-page-title-main">Phi Cygni</span> Star in the constellation Cygnus

Phi Cygni, Latinized from φ Cygni, is a binary star system in the northern constellation of Cygnus. It is faintly visible to the naked eye with an apparent visual magnitude of 4.70. The annual parallax shift is 12.25 mas as measured from Earth, which yields a distance estimate of around 266 light years. It is moving further from the Sun with a radial velocity of +4.5 km/s.

63 Cygni is a single star in the northern constellation of Cygnus, located around 1,030 light years away from Sun. It is visible to the naked eye as an orange-hued star with an apparent visual magnitude of 4.56. 63 Cyg is moving closer to the Earth with a heliocentric radial velocity of −26 km/s.

15 Cygni is a single star in the northern constellation Cygnus. With an apparent visual magnitude of 4.90, it is a faint star but visible to the naked eye. The distance to 15 Cygni can be estimated from its annual parallax shift of 11.0 mas, which yields a separation of some 296 light years. It is moving closer to the Sun with a heliocentric radial velocity of −23.6 km/s.

109 Herculis is a single star in the northern constellation of Hercules. It is visible to the naked eye as a faint, orange-hued point of light with an apparent visual magnitude of 3.84. The star is located around 121 light-years distant, based on parallax. It is moving closer to the Earth with a heliocentric radial velocity of −58 km/s, and may come as close as 81 light-years away in around 328,000 years.

Phi3 Hydrae is a binary star in the equatorial constellation of Hydra. It originally received the Flamsteed designation of 2 Crateris before being placed in the Hydra constellation. Based upon an annual parallax shift of 15.49 mas as seen from Earth, it is located around 211 light years from the Sun. It is visible to the naked eye with an apparent visual magnitude of 4.90. It forms a triangle with the fainter φ1 Hydrae and φ2 Hydrae, between μ Hydrae and ν Hydrae.

HD 82741 is a single star in the northern constellation of Lynx. It is visible to the naked eye with an apparent visual magnitude of 4.81. The distance to HD 82741 is 223 light years, as determined from its annual parallax shift of 14.6 mas. It is moving further from the Earth with a heliocentric radial velocity of 1 km/s.

<span class="mw-page-title-main">35 Pegasi</span> Star in the constellation of Pegasus

35 Pegasi is a single star in the northern constellation of Pegasus. It is visible to the naked eye as a faint, orange-hued point of light with an apparent visual magnitude of 4.80. The star is located approximately 155 light years away from the Sun based on parallax, and is drifting further away with a radial velocity of +54 km/s. The star has a relatively high proper motion, traversing the celestial sphere at the rate of 0.318 arc seconds per annum.

20 Cygni is a single, orange-hued star in the northern constellation of Cygnus. It is a faint star but is visible to the naked eye with an apparent visual magnitude of 5.03. The distance to 20 Cygni can be estimated from its annual parallax shift of 16 mas, which yields a range of 202 light years. It is moving closer to the Earth with a heliocentric radial velocity of −22 km/s.

References

  1. 1 2 3 4 5 6 7 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv: 2208.00211 . Bibcode:2023A&A...674A...1G. doi: 10.1051/0004-6361/202243940 . S2CID   244398875. Gaia DR3 record for this source at VizieR.
  2. 1 2 3 4 Oja, T. (August 1986), "UBV photometry of stars whose positions are accurately known. III", Astronomy and Astrophysics Supplement Series, 65 (2): 405–409, Bibcode:1986A&AS...65..405O.
  3. 1 2 Morgan, W. W.; Keenan, P. C. (1973), "Spectral Classification", Annual Review of Astronomy and Astrophysics, 11: 29–50, Bibcode:1973ARA&A..11...29M, doi:10.1146/annurev.aa.11.090173.000333.
  4. ↑ Cardini, D. (January 2005), "Mg II chromospheric radiative loss rates in cool active and quiet stars", Astronomy and Astrophysics, 430: 303–311, arXiv: astro-ph/0409683 , Bibcode:2005A&A...430..303C, doi:10.1051/0004-6361:20041440, S2CID   12136256.
  5. 1 2 3 4 5 6 Kallinger, T.; Beck, P. G.; Hekker, S.; Huber, D.; Kuschnig, R.; Rockenbauer, M.; Winter, P. M.; Weiss, W. W.; Handler, G.; Moffat, A. F. J.; Pigulski, A.; Popowicz, A.; Wade, G. A.; Zwintz, K. (2019-04-01), "Stellar masses from granulation and oscillations of 23 bright red giants observed by BRITE-Constellation", Astronomy & Astrophysics, 624: A35, arXiv: 1902.07531 , Bibcode:2019A&A...624A..35K, doi:10.1051/0004-6361/201834514, ISSN   0004-6361
  6. ↑ Luck, R. Earle (September 2015), "Abundances in the Local Region. I. G and K Giants", The Astronomical Journal, 150 (3): 23, arXiv: 1507.01466 , Bibcode:2015AJ....150...88L, doi:10.1088/0004-6256/150/3/88, S2CID   118505114, 88.
  7. ↑ Massarotti, Alessandro; et al. (January 2008), "Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity", The Astronomical Journal, 135 (1): 209–231, Bibcode:2008AJ....135..209M, doi: 10.1088/0004-6256/135/1/209 , S2CID   121883397.
  8. ↑ "eta Cyg". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2017-02-19.
  9. ↑ Marett-Crosby, Michael (2013), Twenty-Five Astronomical Observations That Changed the World: And How To Make Them Yourself, The Patrick Moore Practical Astronomy Series, Springer Science & Business Media, p. 231, ISBN   978-1461468004.
  10. ↑ Puzeras, E.; et al. (October 2010), "High-resolution spectroscopic study of red clump stars in the Galaxy: iron-group elements", Monthly Notices of the Royal Astronomical Society, 408 (2): 1225–1232, arXiv: 1006.3857 , Bibcode:2010MNRAS.408.1225P, doi: 10.1111/j.1365-2966.2010.17195.x , S2CID   44228180.
  11. ↑ Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466–3471, Bibcode:2001AJ....122.3466M, doi: 10.1086/323920 .
  12. ↑ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society , 389 (2): 869–879, arXiv: 0806.2878 , Bibcode:2008MNRAS.389..869E, doi: 10.1111/j.1365-2966.2008.13596.x , S2CID   14878976.
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