Nu Octantis

Nu Octantis (afgekort as ν Oct) is ’n spektroskopiese dubbelster^[8] in die sterrebeeld Oktant met ’n wentelperiode van sowat 2,9 jaar.^[7] Met sy skynbare magnitude van 3,73^[3] is dit die helderste ster in die sterrebeeld. Dit is sowat 69,1 ligjare van die Son af.^[2] Die primêre ster is ’n oranje reusester van spektraaltipe K1 III,^[1] en is dus ’n ster wat die waterstof in sy kern opgebruik en uitgesit het. Die sekondêre ster is waarskynlik ’n rooidwerg met ’n lae massa.^[4]

Nu Octantis
Die ligging van Nu Octantis (in die rooi sirkel).
Sterrebeeld	Oktant
Spektraaltipe	K1 III[1]
Soort	Dubbelster
Waarnemingsdata (Epog J2000)
Regte klimming	21h 41m 28.64977s[2]
Deklinasie	-77° 23′ 24.1563″[2]
Skynmagnitude (m)	3,73[3]
Absolute magnitude (M)	2,1[3] +2,02[4]
B-V-kleurindeks	+1.00[5]
U-B-kleurindeks	+0,89[5]
Besonderhede
Massa (M☉)	1,04[6] 1,61 / 0,585[4]
Radius (R☉)	5,9[6] 5,81 ± 0,12[4]
Ligsterkte (L☉)	17,53[3]
Ouderdom (jaar)	~2,5-3 miljard[4]
Temperatuur (K)	4 860 ± 40[7]
Afstand (ligjaar)	69,1
Rotasiespoed (km/s)	2[4]
Metaalinhoud [Fe/H]	0,18 ± 0,04[4]
Ander name
CD-77 1079, CCDM J21415-7723A, FK5 810, GC 30289, GJ 9744, HIP 107089, HR 8254, HD 205478, SAO 257948, WDS J21415-7723A
Portaal    Sterrekunde

In 2009 is voorgestel die stelsel het ’n eksoplaneet, geskoei op versteurings in die wentelperiode.^[7] Die versteurings kan egter daaraan toegeskryf word dat die sekondêre ster self ’n dubbelster is,^[9] aangesien die vorming van ’n planeet in so ’n stelsel moeilik sal wees vanweë dinamiese versteurings.^[10]

Verwysings

1. Gray, R. O.; et al. (Julie 2006). "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample". The Astronomical Journal. 132 (1): 161–170. arXiv:astro-ph/0603770. Bibcode:2006AJ....132..161G. doi:10.1086/504637.
2. Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. Vizier-katalogus
3. Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. Vizier-katalogus
4. Ramm, D. J.; et al. (2016). "The conjectured S-type retrograde planet in ν Octantis: more evidence including four years of iodine-cell radial velocities". Monthly Notices of the Royal Astronomical Society. 460 (4): 3706–3719. arXiv:1605.06720. Bibcode:2016MNRAS.460.3706R. doi:10.1093/mnras/stw1106.
5. Mallama, A. (2014). "Sloan Magnitudes for the Brightest Stars". The Journal of the American Association of Variable Star Observers. 42: 443. Bibcode:2014JAVSO..42..443M.Vizier-katalogus
6. Allende Prieto, C.; Lambert, D. L. (1999). "Fundamental parameters of nearby stars from the comparison with evolutionary calculations: Masses, radii and effective temperatures". Astronomy and Astrophysics. 352: 555. arXiv:astro-ph/9911002. Bibcode:1999A&A...352..555A. Vizier-katalogus
7. Ramm, D. J.; Pourbaix, D.; Hearnshaw, J. B.; Komonjinda, S. (April 2009). "Spectroscopic orbits for K giants β Reticuli and ν Octantis: what is causing a low-amplitude radial velocity resonant perturbation in ν Oct?". Monthly Notices of the Royal Astronomical Society. 394 (3): 1695–1710. Bibcode:2009MNRAS.394.1695R. doi:10.1111/j.1365-2966.2009.14459.x.
8. 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.
9. Morais, M. H. M.; Correia, A. C. M. (Februarie 2012). "Precession due to a close binary system: an alternative explanation for ν-Octantis?". Monthly Notices of the Royal Astronomical Society. 419 (4): 3447–3456. arXiv:1110.3176. Bibcode:2012MNRAS.419.3447M. doi:10.1111/j.1365-2966.2011.19986.x.
10. Gozdziewski, K.; Slonina, M.; Migaszewski, C.; Rozenkiewicz, A. (Maart 2013). "Testing a hypothesis of the ν Octantis planetary system". Monthly Notices of the Royal Astronomical Society. 430 (1): 533–545. arXiv:1205.1341. Bibcode:2013MNRAS.430..533G. doi:10.1093/mnras/sts652.

Eksterne skakels

• Hierdie artikel is vertaal uit die Engelse Wikipedia