Unukalhai

Unukalhai
	Unukalhai se ligging (in die rooi sirkel).
Sterrebeeld	Slang
Bayer-naam	Alpha Serpentis
Spektraaltipe	K2 III
Soort	Reusester
	Waarnemingsdata (Epog J2000)
Regte klimming	15h 44m 16.07431s
Deklinasie	+06° 25′ 32.2633″
Skynmagnitude (m)	2,623
Absolute magnitude (M)	0,88 ± 0,03
B-V-kleurindeks	+1,167
U-B-kleurindeks	+1,248
	Besonderhede
Radius (R☉)	12
Ligsterkte (L☉)	70
Temperatuur (K)	4 498
Afstand (ligjaar)	74
Rotasiespoed (km/s)	4,3
Metaalinhoud [Fe/H]	0,03
	Ander name
	Cor Serpentis, 24 Serpentis, HR 5854, HD 140573, SAO 121157, HIP 77070, BD+06° 3088, ADS 9765, CCDM 15442+0626
Portaal	Sterrekunde

Unukalhai (ook bekend as Alpha Serpentis of α Ser) is ’n dubbelster in die kop van die sterrebeeld Slang (Serpens). Met ’n skynbare magnitude van 2,6^[2] is dit die helderste ster in die sterrebeeld en kan dit van die grootste deel van die Aarde af met die blote oog gesien word. Volgens parallaksmetings is dit sowat 74 ligjare van die Son af.

Eienskappe

Alpha Serpentis is ’n reusester met ’n sterreklassifikasie van K2 III, wat beteken dit het al die waterstof in sy kern opgebruik en weg van die hoofreeks geëvolueer. Sy geraamde radius is sowat 12 keer dié van die Son.^[4] Sy effektiewe temperatuur van 4 498 K^[6] gee dit die oranje kleur wat tipes is van K-tipe sterre.^[8]

Die ster straal sowat 38 keer die ligsterkte van die Son uit en nog 32 keer in die infrarooi, dus altesaam 70 keer soveel.^[5] ’n Metgeselster met ’n skynbare magnitude van 11.8 kom by ’n hoekskeiding van 58 boogsekondes van Alpha Serpentis af voor, terwyl ’n ster van die 13de magnitude 2,3 boogminute weg is.

Name

Die ster se Bayer-naam is "Alpha Serpentis" en sy Flamsteed-naam "24 Serpentis". Sy tradisionele naam "Unukalhai" (ook Unuk al Hay of Unuk Elhaija gespel) kom van die Arabiese عنق الحيّة ʽunuq al-ḥayyah, "die slang se nek", en die naam "Cor Serpentis" van die Latyn vir "die hart van die slang". In 2016 het die Internasionale Astronomiese Unie se sternaamwerkgroep (WGSN) die naam "Unukalhai" vir die ster goedgekeur.^[9]^[10]

Verwysings

↑ ^1,0 ^1,1 van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V
↑ ^2,0 ^2,1 ^2,2 ^2,3 Gutierrez-Moreno, Adelina et al. (1966), A System of photometric standards, 1, Publicaciones Universidad de Chile, Department de Astronomy, pp. 1–17, Bibcode: 1966PDAUC...1....1G
↑ Carney, Bruce W. et al. (Maart 2008), "Rotation and Macroturbulence in Metal-Poor Field Red Giant and Red Horizontal Branch Stars", The Astronomical Journal 135 (3): 892–906, doi:10.1088/0004-6256/135/3/892, Bibcode: 2008AJ....135..892C
↑ ^4,0 ^4,1 Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, 1 (3de ed.), Birkhäuser, ISBN 3-540-29692-1, https://books.google.com/books?id=OvTjLcQ4MCQC&pg=PA41 .
↑ ^5,0 ^5,1 Kaler, James B., "UNUKALHAI (Alpha Serpentis)", Stars (University of Illinois), http://stars.astro.illinois.edu/sow/unukalhai.html, besoek op 2012-01-11
↑ ^6,0 ^6,1 ^6,2 ^6,3 Massarotti, Alessandro et al. (Januarie 2008), "Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity", The Astronomical Journal 135 (1): 209–231, doi:10.1088/0004-6256/135/1/209, Bibcode: 2008AJ....135..209M
↑ "UNUKALHAI -- Star in double system", SIMBAD (Centre de Données astronomiques de Strasbourg), http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=Beta+Pyx, besoek op 2012-01-11
↑ "The Colour of Stars", Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), 21 Desember 2004, archived from the original on 10 Maart 2012, https://www.webcitation.org/6630AbtJZ?url=http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html, besoek op 2012-01-16
↑ Kunitzsch, Paul; Smart, Tim (2006). A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations (2de hers. uitg.). Cambridge, Massachusetts: Sky Pub. ISBN 978-1-931559-44-7.
↑ "IAU Catalog of Star Names" (in Engels). Geargiveer vanaf die oorspronklike op 11 Mei 2020. Besoek op 28 Julie 2016.

Eksterne skakels

Hierdie artikel is vertaal uit die Engelse Wikipedia

[aaa474_2_653-1] 1,0 ^1,1 van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V

[sps1966-2] 2,0 ^2,1 ^2,2 ^2,3 Gutierrez-Moreno, Adelina et al. (1966), A System of photometric standards, 1, Publicaciones Universidad de Chile, Department de Astronomy, pp. 1–17, Bibcode: 1966PDAUC...1....1G

[aj135_3_892-3] Carney, Bruce W. et al. (Maart 2008), "Rotation and Macroturbulence in Metal-Poor Field Red Giant and Red Horizontal Branch Stars", The Astronomical Journal 135 (3): 892–906, doi:10.1088/0004-6256/135/3/892, Bibcode: 2008AJ....135..892C

[lang2006-4] 4,0 ^4,1 Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, 1 (3de ed.), Birkhäuser, ISBN 3-540-29692-1, https://books.google.com/books?id=OvTjLcQ4MCQC&pg=PA41 .

[kaler-5] 5,0 ^5,1 Kaler, James B., "UNUKALHAI (Alpha Serpentis)", Stars (University of Illinois), http://stars.astro.illinois.edu/sow/unukalhai.html, besoek op 2012-01-11

[aj135_1_209-6] 6,0 ^6,1 ^6,2 ^6,3 Massarotti, Alessandro et al. (Januarie 2008), "Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity", The Astronomical Journal 135 (1): 209–231, doi:10.1088/0004-6256/135/1/209, Bibcode: 2008AJ....135..209M

[SIMBAD-7] "UNUKALHAI -- Star in double system", SIMBAD (Centre de Données astronomiques de Strasbourg), http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=Beta+Pyx, besoek op 2012-01-11

[csiro-8] "The Colour of Stars", Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), 21 Desember 2004, archived from the original on 10 Maart 2012, https://www.webcitation.org/6630AbtJZ?url=http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html, besoek op 2012-01-16

[Kunitzsch-9] Kunitzsch, Paul; Smart, Tim (2006). A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations (2de hers. uitg.). Cambridge, Massachusetts: Sky Pub. ISBN 978-1-931559-44-7.

[IAU-CSN-10] "IAU Catalog of Star Names" (in Engels). Geargiveer vanaf die oorspronklike op 11 Mei 2020. Besoek op 28 Julie 2016.

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