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	Goombridge 1618
Observationsdata; Epok: J2000.0
Stjärnbild	Stora björnen
Rektascension	10t 11m 22,13995s
Deklination	+49° 27′ 15,2510″
Skenbar magnitud ()	+6,60
Stjärntyp
Spektraltyp	K7.5 Ve
U–B	+1,27
B–V	+1,34
Variabeltyp	BY Draconis-variabel, Flarestjärna
Astrometri
Radialhastighet ()	-26,48 ± 0,12 km/s
Egenrörelse (µ)	RA: -1 363,287 ± 0,016 mas/år; Dek.: -505,770 ± mas/år
Parallax ()	205,3148 ± 0,0224
Avstånd	15,886 ± 0,002 lå (4,8706 ± 0,0005 pc)
Absolut magnitud ()	+8,11
Detaljer
Massa	0,670 ± 0,033 M☉
Radie	0,605 ± 0,02 R☉
Luminositet	0,15 L☉
Temperatur	3 970 ± 51 K
Metallicitet	-0,03
Vinkelhastighet	2,8 km/s
Ålder	6,6 miljarder år
Andra beteckningar
	HD 88230, AG+49 914, AP J10112218+4927153, BD+50 1725, CCDM J10114+4927A, DO 33188, 2E 2238, G 196-9, GJ 380, HIC 49908, HIP 49908, IRAS 10082+4942, LHS 280, LSPM J1011+4927, 2MASS J10112218+4927153, NLTT 23613, NSV 4765, PLX 2390, PPM 51736, 1RXS J101124.1+492718, SAO 43223, TYC 3437-811-1, UCAC4 698-052810, USNO-B1.0, 1394-00210100, uvby98 100088230, WDS J10114+4927A, WISEA J101120.70+492709.9, YZC 26 3582, [GKL99] 214, Gaia DR2 823773494718931968, Gaia DR3 823773494718931968

Groombridge 1618 eller HD 88230, är en ensam stjärna i mellersta delen av stjärnbilden Stora björnen. Den har en skenbar magnitud av ca 6,60^[2] och kräver åtminstone en handkikare för att kunna observeras. Baserat på parallax enligt Gaia Data Release 3 på ca 205,3 mas^[1] beräknas den befinna sig på ett avstånd av ca 15,9 ljusår (ca 4,87 parsec) solen. Den rör sig närmare solen med en heliocentrisk radialhastighet av ca -26 km/s.^[1]

Observation

Stjärnan identifierades först som post 1618 i A Catalog of Circumpolar Stars av Stephen Groombridge, publicerad postumt 1838.^[12] Den har en sådan egenrörelse över himlen att den kunde noteras vara belägen ganska nära, vilket gjorde den till en tidig kandidat för parallaxmätningar. År 1884 mättes parallaxvinkeln till 0,322 ± 0,023 bågsekund, vilket är större än det moderna värdet på 0,205 bågsekund.^[13]

Egenskaper

Groombridge 1618 är en orange till gul stjärna i huvudserien av spektralklass K7.5 V,^[3] som genererar energi genom kärnfusion av väte i dess kärna. Den har en massa av ca 0,67^[6] solmassa, en radie av ca 0,61^[6] solradie och utsänder energi från dess fotosfär motsvarande ca 0,15^[7] gånger solen vid en effektiv temperatur av ca 4 000 K.^[8] Stjärnan är en BY Draconis-variabel med en magnetisk ytstyrka på 750 G.^[14] Kromosfären är relativt inaktiv^[15] och producerar stjärnfläckar jämförbara med solfläckar. Men liksom UV Ceti har den observerats genomgå ökningar i ljusstyrka som en flarestjärna.^[4]

Referenser

Den här artikeln är helt eller delvis baserad på material från engelskspråkiga Wikipedia, Groombridge 1618, 14 maj 2023..

Noter

^ [a b c d e f g h] 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.
^ [a b c d] Argue, A. N. (1966), "UBV photometry of 550 F, G and K type stars", Monthly Notices of the Royal Astronomical Society, 133 (4): 475–493, Bibcode:1966MNRAS.133..475A, doi:10.1093/mnras/133.4.475
^ [a b c] Lépine, Sébastien; et al. (2013), "A Spectroscopic Catalog of the Brightest (J < 9) M Dwarfs in the Northern Sky", The Astronomical Journal, 145 (4): 102, arXiv:1206.5991, Bibcode:2013AJ....145..102L, doi:10.1088/0004-6256/145/4/102, S2CID 117144290.
^ [a b] Andrillat, Y.; Morguleff, N. (1967), Hack, Margherita (ed.), "Three potassium-flare stars", Proceedings of the Colloquium, held in Trieste, June 13–17, 1966, Trieste, p. 160, Bibcode:1967lts..conf..160A.
^ Holmberg, J.; et al. (July 2009), "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics", Astronomy and Astrophysics, 501 (3): 941–947, arXiv:0811.3982, Bibcode:2009A&A...501..941H, doi:10.1051/0004-6361/200811191, S2CID 118577511.
^ [a b c d] Ségransan, Damien; Kervella, Pierre; Forveille, Thierry; Queloz, Didier (2003). "First radius measurements of very low mass stars with the VLTI". Astronomy and Astrophysics. 397 (3): L5–L8. arXiv:astro-ph/0211647. Bibcode:2003A&A...397L...5S. doi:10.1051/0004-6361:20021714. S2CID 10748478.
^ [a b c] Eiroa, C.; et al. (December 2011), "Herschel discovery of a new class of cold, faint debris discs", Astronomy & Astrophysics, 536: L4, arXiv:1110.4826, Bibcode:2011A&A...536L...4E, doi:10.1051/0004-6361/201117797, S2CID 14234038.
^ [a b c] Woolf, Vincent M.; Wallerstein, George (January 2005). "Metallicity measurements using atomic lines in M and K dwarf stars". Monthly Notices of the Royal Astronomical Society. 356 (3): 963–968. arXiv:astro-ph/0410452. Bibcode:2005MNRAS.356..963W. doi:10.1111/j.1365-2966.2004.08515.x. S2CID 15664454. See table 3.
^ López-Morales, Mercedes (May 2007). "On the Correlation between the Magnetic Activity Levels, Metallicities, and Radii of Low-Mass Stars". The Astrophysical Journal. 660 (1): 732–739. arXiv:astro-ph/0701702. Bibcode:2007ApJ...660..732L. doi:10.1086/513142. S2CID 119530297.
^ Hämtad 2024-07-08.
^ "NSV 4765 -- Flare Star". SIMBAD. Centre de Données astronomiques de Strasbourg. Hämtad 2013-08-01.
^ Dyson, F. W.; Thackeray, W. G.; Christie, W. H. M. (1905). "New reduction of Groombridge's catalogue of circumpolar stars". Proceedings of the Royal Society of Edinburgh. Bibcode:1905Gmb...C......0D.
^ Ball, Robert S. (1884). "On the Annual Parallax of Groombridge 1618". Dunsink Observatory Publications. 5 (2): 187–217. Bibcode:1884DunOP...5..187B.
^ Gudel, M. (October 1992), "Radio and X-ray emission from main-sequence K stars", Astronomy and Astrophysics, 264 (2): L31–L34, Bibcode:1992A&A...264L..31G.
^ Byrne, P. B.; Doyle, J. G. (November 1990), "Activity in late-type stars. VII - Chromospheric and transition region line fluxes in 2 dM and 1 dM(e) stars", Astronomy and Astrophysics, 238 (1–2): 221–226, Bibcode:1990A&A...238..221B.

[A-1] [a b c d e f g h] 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.

[B-2] [a b c d] Argue, A. N. (1966), "UBV photometry of 550 F, G and K type stars", Monthly Notices of the Royal Astronomical Society, 133 (4): 475–493, Bibcode:1966MNRAS.133..475A, doi:10.1093/mnras/133.4.475

[C-3] [a b c] Lépine, Sébastien; et al. (2013), "A Spectroscopic Catalog of the Brightest (J < 9) M Dwarfs in the Northern Sky", The Astronomical Journal, 145 (4): 102, arXiv:1206.5991, Bibcode:2013AJ....145..102L, doi:10.1088/0004-6256/145/4/102, S2CID 117144290.

[E-4] [a b] Andrillat, Y.; Morguleff, N. (1967), Hack, Margherita (ed.), "Three potassium-flare stars", Proceedings of the Colloquium, held in Trieste, June 13–17, 1966, Trieste, p. 160, Bibcode:1967lts..conf..160A.

[F-5] Holmberg, J.; et al. (July 2009), "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics", Astronomy and Astrophysics, 501 (3): 941–947, arXiv:0811.3982, Bibcode:2009A&A...501..941H, doi:10.1051/0004-6361/200811191, S2CID 118577511.

[G-6] [a b c d] Ségransan, Damien; Kervella, Pierre; Forveille, Thierry; Queloz, Didier (2003). "First radius measurements of very low mass stars with the VLTI". Astronomy and Astrophysics. 397 (3): L5–L8. arXiv:astro-ph/0211647. Bibcode:2003A&A...397L...5S. doi:10.1051/0004-6361:20021714. S2CID 10748478.

[H-7] [a b c] Eiroa, C.; et al. (December 2011), "Herschel discovery of a new class of cold, faint debris discs", Astronomy & Astrophysics, 536: L4, arXiv:1110.4826, Bibcode:2011A&A...536L...4E, doi:10.1051/0004-6361/201117797, S2CID 14234038.

[J-8] [a b c] Woolf, Vincent M.; Wallerstein, George (January 2005). "Metallicity measurements using atomic lines in M and K dwarf stars". Monthly Notices of the Royal Astronomical Society. 356 (3): 963–968. arXiv:astro-ph/0410452. Bibcode:2005MNRAS.356..963W. doi:10.1111/j.1365-2966.2004.08515.x. S2CID 15664454. See table 3.

[K-9] López-Morales, Mercedes (May 2007). "On the Correlation between the Magnetic Activity Levels, Metallicities, and Radii of Low-Mass Stars". The Astrophysical Journal. 660 (1): 732–739. arXiv:astro-ph/0701702. Bibcode:2007ApJ...660..732L. doi:10.1086/513142. S2CID 119530297.

[SIMBAD-10] Hämtad 2024-07-08.

[L-11] "NSV 4765 -- Flare Star". SIMBAD. Centre de Données astronomiques de Strasbourg. Hämtad 2013-08-01.

[M-12] Dyson, F. W.; Thackeray, W. G.; Christie, W. H. M. (1905). "New reduction of Groombridge's catalogue of circumpolar stars". Proceedings of the Royal Society of Edinburgh. Bibcode:1905Gmb...C......0D.

[N-13] Ball, Robert S. (1884). "On the Annual Parallax of Groombridge 1618". Dunsink Observatory Publications. 5 (2): 187–217. Bibcode:1884DunOP...5..187B.

[D-14] Gudel, M. (October 1992), "Radio and X-ray emission from main-sequence K stars", Astronomy and Astrophysics, 264 (2): L31–L34, Bibcode:1992A&A...264L..31G.

[O-15] Byrne, P. B.; Doyle, J. G. (November 1990), "Activity in late-type stars. VII - Chromospheric and transition region line fluxes in 2 dM and 1 dM(e) stars", Astronomy and Astrophysics, 238 (1–2): 221–226, Bibcode:1990A&A...238..221B.

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