  | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Hydra |
| Right ascension | 08h 55m 23.62614s [1] |
| Declination | +05° 56′ 44.0354″ [1] |
| Apparent magnitude (V) | 3.10 [2] |
| Characteristics | |
| Spectral type | G9 II-III [3] |
| U−B color index | +0.82 [2] |
| B−V color index | +1.00 [2] |
| Astrometry | |
| Radial velocity (Rv) | +22.8 [4] km/s |
| Proper motion (μ) |
RA: –100.06
[1]
mas/
yr Dec.: +15.46 [1] mas/ yr |
| Parallax (π) | 19.51 ± 0.18 mas [1] |
| Distance | 167 ± 2
ly (51.3 ± 0.5 pc) |
| Absolute magnitude (MV) | –0.24 [5] |
| Details | |
| Mass | 4.2 [6] M☉ |
| Radius | 17.9 [7] R☉ |
| Luminosity | 132 [7] L☉ |
| Surface gravity (log g) | 2.48 [7] cgs |
| Temperature | 4,925 [6] K |
| Metallicity [Fe/H] | –0.21 [8] dex |
| Rotational velocity (v sin i) | 2.5 [8] km/s |
| Age | 400 [5] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Zeta Hydrae (ζ Hya, ζ Hydrae) is a solitary star in the equatorial constellation of Hydra. This is a generally faint constellation, so, at an apparent visual magnitude of +3.10, [2] this is the third-brightest member after Alphard and Gamma Hydrae.
Distance
The distance to this star has been measured using the parallax technique, yielding a value of roughly 167 light-years (51 parsecs). [1] At this distance, the visual magnitude of the star is diminished by 0.03 as a result of extinction from intervening gas and dust. [5] Delta Hydrae is about 12.9 light-years (4.0 parsecs) from Zeta Hydrae and may be a largely co-moving object. [10] The star has one of the lower-error margin readings among those of the Gaia spacecraft which computes a parallax of 20.7182 ± 0.3925 mas and, if correct, a distance of 157 ± 3 light years. [11]
Characteristics
With a stellar classification of G9 II-III, [3] this is an evolved giant star that is radiating 132 [7] times the luminosity of the Sun from its outer envelope at an effective temperature of 4,925 K. [6] At this heat, the star glows with the yellow hue of a G-type star. [12] The radius of this star, as measured using interferometry, is about 18 times the Sun's radius. [7] It has an estimated 4.2 times the mass of the Sun [6] and is around 400 million years old. [5]
Name and etymology
This star, along with δ Hya (Lisan al Sudja), ε Hya, η Hya, ρ Hya and σ Hya (Minchir), were Ulug Beg's Min al Azʽal, "Belonging to the Uninhabited Spot". [13] According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, Min al Azʽal or Minazal were the title for five stars: δ Hya as Minazal I, η Hya as Minazal II, ε Hya as Minazal III, ρ Hya as Minazal IV and ζ Hya as Minazal V (exclude σ Hya). [14]
In Chinese, 柳宿 (Liǔ Sù), meaning Willow, refers to an asterism consisting of ζ Hydrae, δ Hydra, σ Hydrae, η Hydrae, ρ Hydrae, ε Hydrae, ω Hydrae and θ Hydrae [15] Consequently, ζ Hydrae itself is known as 柳宿六 (Liǔ Sù liù, English: the Sixth Star of Willow). [16]
The people of Groote Eylandt called Unwala, "The Crab", for the star cluster including this star, δ Hya (Lisan al Sudja), ε Hya, η Hya, ρ Hya and σ Hya (Minchir). [17]
References
- ^ a b c d e f van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv: 0708.1752, Bibcode: 2007A&A...474..653V, doi: 10.1051/0004-6361:20078357, S2CID 18759600
- ^ a b c d Jennens, P. A.; Helfer, H. L. (September 1975), "A new photometric metal abundance and luminosity calibration for field G and K giants.", Monthly Notices of the Royal Astronomical Society, 172 (3): 667–679, Bibcode: 1975MNRAS.172..667J, doi: 10.1093/mnras/172.3.667
- ^ a b Morgan, W. W.; Keenan, P. C. (1973), "Spectral Classification", Annual Review of Astronomy and Astrophysics, 11 (1): 29–50, Bibcode: 1973ARA&A..11...29M, doi: 10.1146/annurev.aa.11.090173.000333
- ^ Wielen, R.; et al. (1999), "Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions", Veroeffentlichungen des Astronomischen Rechen-Instituts Heidelberg, 35 (35), Astronomisches Rechen-Institut Heidelberg: 1, Bibcode: 1999VeARI..35....1W
- ^ a b c d Takeda, Yoichi; Sato, Bun'ei; Murata, Daisuke (August 2008), "Stellar parameters and elemental abundances of late-G giants", Publications of the Astronomical Society of Japan, 60 (4): 781–802, arXiv: 0805.2434, Bibcode: 2008PASJ...60..781T, doi: 10.1093/pasj/60.4.781, S2CID 16258166
- ^ a b c d Ando, Hiroyasu; et al. (April 2008), "Detection of Small-Amplitude Oscillations in the G-Giant HD76294 (ξ Hydrae)", Publications of the Astronomical Society of Japan, 60 (2): 219–222, Bibcode: 2008PASJ...60..219A, doi: 10.1093/pasj/60.2.219
- ^ a b c d e Ando, Hiroyasu; Tsuboi, Yusuke; Kambe, Eiji; Sato, Bun'ei (August 2010), "Oscillations in G-Type Giants", Publications of the Astronomical Society of Japan, 62 (4): 1117–1126, arXiv: 1007.1286, Bibcode: 2010PASJ...62.1117A, doi: 10.1093/pasj/62.4.1117, S2CID 118677219
- ^ a b 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
- ^ "zet Hya". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2006-11-05.
- ^ Shaya, Ed J.; Olling, Rob P. (January 2011), "Very Wide Binaries and Other Comoving Stellar Companions: A Bayesian Analysis of the Hipparcos Catalogue", The Astrophysical Journal Supplement, 192 (1): 2, arXiv: 1007.0425, Bibcode: 2011ApJS..192....2S, doi: 10.1088/0067-0049/192/1/2, S2CID 119226823
- ^ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv: 1804.09365. Bibcode: 2018A&A...616A...1G. doi: 10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on 2013-12-03, retrieved 2012-01-16
- ^ Allen, R. H. (1963), Star Names: Their Lore and Meaning (Reprint ed.), New York, NY: Dover Publications Inc, p. 249, ISBN 0-486-21079-0, retrieved 2010-12-12
- ^ Rhoads, Jack W. (November 15, 1971), Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars (PDF), Jet Propulsion Laboratory, California Institute of Technology
- ^ (in Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
- ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 28 日
- ^ Selin, Helaine, ed. (1997), Encyclopaedia of the history of science, technology, and medicine in non-western cultures, Dordrecht: Kluwer Academic Publishers, p. 105, ISBN 9780792340669
| |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Hydra |
| Right ascension | 08h 55m 23.62614s [1] |
| Declination | +05° 56′ 44.0354″ [1] |
| Apparent magnitude (V) | 3.10 [2] |
| Characteristics | |
| Spectral type | G9 II-III [3] |
| U−B color index | +0.82 [2] |
| B−V color index | +1.00 [2] |
| Astrometry | |
| Radial velocity (Rv) | +22.8 [4] km/s |
| Proper motion (μ) |
RA: –100.06
[1]
mas/
yr Dec.: +15.46 [1] mas/ yr |
| Parallax (π) | 19.51 ± 0.18 mas [1] |
| Distance | 167 ± 2
ly (51.3 ± 0.5 pc) |
| Absolute magnitude (MV) | –0.24 [5] |
| Details | |
| Mass | 4.2 [6] M☉ |
| Radius | 17.9 [7] R☉ |
| Luminosity | 132 [7] L☉ |
| Surface gravity (log g) | 2.48 [7] cgs |
| Temperature | 4,925 [6] K |
| Metallicity [Fe/H] | –0.21 [8] dex |
| Rotational velocity (v sin i) | 2.5 [8] km/s |
| Age | 400 [5] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Zeta Hydrae (ζ Hya, ζ Hydrae) is a solitary star in the equatorial constellation of Hydra. This is a generally faint constellation, so, at an apparent visual magnitude of +3.10, [2] this is the third-brightest member after Alphard and Gamma Hydrae.
Distance
The distance to this star has been measured using the parallax technique, yielding a value of roughly 167 light-years (51 parsecs). [1] At this distance, the visual magnitude of the star is diminished by 0.03 as a result of extinction from intervening gas and dust. [5] Delta Hydrae is about 12.9 light-years (4.0 parsecs) from Zeta Hydrae and may be a largely co-moving object. [10] The star has one of the lower-error margin readings among those of the Gaia spacecraft which computes a parallax of 20.7182 ± 0.3925 mas and, if correct, a distance of 157 ± 3 light years. [11]
Characteristics
With a stellar classification of G9 II-III, [3] this is an evolved giant star that is radiating 132 [7] times the luminosity of the Sun from its outer envelope at an effective temperature of 4,925 K. [6] At this heat, the star glows with the yellow hue of a G-type star. [12] The radius of this star, as measured using interferometry, is about 18 times the Sun's radius. [7] It has an estimated 4.2 times the mass of the Sun [6] and is around 400 million years old. [5]
Name and etymology
This star, along with δ Hya (Lisan al Sudja), ε Hya, η Hya, ρ Hya and σ Hya (Minchir), were Ulug Beg's Min al Azʽal, "Belonging to the Uninhabited Spot". [13] According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, Min al Azʽal or Minazal were the title for five stars: δ Hya as Minazal I, η Hya as Minazal II, ε Hya as Minazal III, ρ Hya as Minazal IV and ζ Hya as Minazal V (exclude σ Hya). [14]
In Chinese, 柳宿 (Liǔ Sù), meaning Willow, refers to an asterism consisting of ζ Hydrae, δ Hydra, σ Hydrae, η Hydrae, ρ Hydrae, ε Hydrae, ω Hydrae and θ Hydrae [15] Consequently, ζ Hydrae itself is known as 柳宿六 (Liǔ Sù liù, English: the Sixth Star of Willow). [16]
The people of Groote Eylandt called Unwala, "The Crab", for the star cluster including this star, δ Hya (Lisan al Sudja), ε Hya, η Hya, ρ Hya and σ Hya (Minchir). [17]
References
- ^ a b c d e f van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv: 0708.1752, Bibcode: 2007A&A...474..653V, doi: 10.1051/0004-6361:20078357, S2CID 18759600
- ^ a b c d Jennens, P. A.; Helfer, H. L. (September 1975), "A new photometric metal abundance and luminosity calibration for field G and K giants.", Monthly Notices of the Royal Astronomical Society, 172 (3): 667–679, Bibcode: 1975MNRAS.172..667J, doi: 10.1093/mnras/172.3.667
- ^ a b Morgan, W. W.; Keenan, P. C. (1973), "Spectral Classification", Annual Review of Astronomy and Astrophysics, 11 (1): 29–50, Bibcode: 1973ARA&A..11...29M, doi: 10.1146/annurev.aa.11.090173.000333
- ^ Wielen, R.; et al. (1999), "Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions", Veroeffentlichungen des Astronomischen Rechen-Instituts Heidelberg, 35 (35), Astronomisches Rechen-Institut Heidelberg: 1, Bibcode: 1999VeARI..35....1W
- ^ a b c d Takeda, Yoichi; Sato, Bun'ei; Murata, Daisuke (August 2008), "Stellar parameters and elemental abundances of late-G giants", Publications of the Astronomical Society of Japan, 60 (4): 781–802, arXiv: 0805.2434, Bibcode: 2008PASJ...60..781T, doi: 10.1093/pasj/60.4.781, S2CID 16258166
- ^ a b c d Ando, Hiroyasu; et al. (April 2008), "Detection of Small-Amplitude Oscillations in the G-Giant HD76294 (ξ Hydrae)", Publications of the Astronomical Society of Japan, 60 (2): 219–222, Bibcode: 2008PASJ...60..219A, doi: 10.1093/pasj/60.2.219
- ^ a b c d e Ando, Hiroyasu; Tsuboi, Yusuke; Kambe, Eiji; Sato, Bun'ei (August 2010), "Oscillations in G-Type Giants", Publications of the Astronomical Society of Japan, 62 (4): 1117–1126, arXiv: 1007.1286, Bibcode: 2010PASJ...62.1117A, doi: 10.1093/pasj/62.4.1117, S2CID 118677219
- ^ a b 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
- ^ "zet Hya". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2006-11-05.
- ^ Shaya, Ed J.; Olling, Rob P. (January 2011), "Very Wide Binaries and Other Comoving Stellar Companions: A Bayesian Analysis of the Hipparcos Catalogue", The Astrophysical Journal Supplement, 192 (1): 2, arXiv: 1007.0425, Bibcode: 2011ApJS..192....2S, doi: 10.1088/0067-0049/192/1/2, S2CID 119226823
- ^ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv: 1804.09365. Bibcode: 2018A&A...616A...1G. doi: 10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on 2013-12-03, retrieved 2012-01-16
- ^ Allen, R. H. (1963), Star Names: Their Lore and Meaning (Reprint ed.), New York, NY: Dover Publications Inc, p. 249, ISBN 0-486-21079-0, retrieved 2010-12-12
- ^ Rhoads, Jack W. (November 15, 1971), Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars (PDF), Jet Propulsion Laboratory, California Institute of Technology
- ^ (in Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
- ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 28 日
- ^ Selin, Helaine, ed. (1997), Encyclopaedia of the history of science, technology, and medicine in non-western cultures, Dordrecht: Kluwer Academic Publishers, p. 105, ISBN 9780792340669