Messier 80
| Messier 79 | |
|---|---|
 | |
| Klotformiga stjärnhopen Messier 79 fotograferad av Hubbleteleskopet . Foto: HST/NASA/ESA | |
| Observationsdata | |
| Stjärnbild | Skorpionen |
| Rektascension | 16t 17m 02,41s[1] |
| Deklination | -22° 58′ 33,9″[1] |
| Klass | II[3] |
| Avstånd | 32 600[2] (10 000 pc) ljusår |
| Skenbar storlek | 10 bågminuter |
| Skenbar magnitud | +7,87[4] |
| Fysiska egenskaper | |
| Massa | 5,2 x 105[5] solmassor |
| Uppskattad ålder | 12,54 miljarder år[6] |
| Upptäckt | |
| Upptäcktsår | 1781 |
| Upptäckare | Charles Messier |
| Andra beteckningar | |
| M80, NGC 6093[4] | |
| Se också: Klotformiga stjärhopar, Lista över klotformiga stjärhopar | |
Messier 80 (M80) även känd som NGC 6093 är en klotformig stjärnhop i stjärnbilden Skorpionen. Den upptäcktes 1781 av Charles Messier. Stjärnhopen ligger, när det gäller dess positionsvinkel från solsystemet, halvvägs mellan Alfa Scorpii (Antares) och Beta Scorpii inom ett område av Vintergatan som är rik på nebulosor. Med låg nivå av ljusföroreningar kan den observeras under den 67:e norra breddgraden med ett amatörteleskop, som visas som en fläckig boll av ljus.
Egenskaper
Messier 80 befinner sig omkring 32 600 ljusår bort från jorden och ligger 60 000 ljusår från Vintergatans centrum. Den ligger på mer än dubbelt så stort avstånd som det galaktiska centret och i regioner som anses vara galaktiska halo. Den har en skenbar vinkeldiameter på ca 10 bågminuter, som på det beräknade avståndet motsvarar en rumslig diameter av ca 95 ljusår.
Messier 80 omfattar flera hundratusen stjärnor, och rankas bland de tätaste klotformiga stjärnhoparna i Vintergatan. Den är värd för relativt många blå eftersläntrare, stjärnor som verkar vara mycket yngre än stjärnhopen. Man tror att dessa har förlorat en del av dess yttre lager på grund av närkontakter med andra stjärnor i hopen eller kanske från kollisioner mellan stjärnor i det täta klustret. Bilder från Rymdteleskopet Hubble har visat uttalade områden med dessa eftersläntrare i M80, vilket tyder på att den centrala delen av hopen har en mycket hög fångst- och kollisionssannolikhet.
Den 21 maj 1860 hittades en nova i M80 som levererade en magnitud av +7,0 till teleskop, kikare och skarpsynta ögon. Denna variabla stjärna, som gavs beteckningen T Scorpii, nådde en absolut magnitud på −8,5 och lyste tillfälligt upp stjärnhopen.
Galleri
M80 ligger längst till höger på denna bild med Rho Ophiuchi molnkomplex uppåt
Karta som visar platsen för M80
Se även
- Messierobjekt
Referenser
- Den här artikeln är helt eller delvis baserad på material från engelskspråkiga Wikipedia, Messier 80, 16 mars 2021.
Noter
- ^ [a b] Goldsbury, Ryan; Richer, Harvey B.; Anderson, Jay; Dotter, Aaron; Sarajedini, Ata; Woodley, Kristin (December 2010), ”The ACS Survey of Galactic Globular Clusters. X. New Determinations of Centers for 65 Clusters”, The Astronomical Journal 140 (6): 1830–1837, doi:, Bibcode: 2010AJ....140.1830G.
- ^ Paust, Nathaniel E. Q.; Reid, I. Neill; Piotto, Giampaolo; Aparicio, Antonio; Anderson, Jay; Sarajedini, Ata; Bedin, Luigi R.; Chaboyer, Brian; et al. (February 2010), ”The ACS Survey of Galactic Globular Clusters. VIII. Effects of Environment on Globular Cluster Global Mass Functions”, The Astronomical Journal 139 (2): 476–491, doi:, Bibcode: 2010AJ....139..476P.
- ^ Shapley, Harlow; Sawyer, Helen B. (August 1927), ”A Classification of Globular Clusters”, Harvard College Observatory Bulletin 849 (849): 11–14, Bibcode: 1927BHarO.849...11S.
- ^ [a b] Messier 80 (u-strasbg.fr). Hämtad 21 november 2006
- ^ Boyles, J.; Lorimer, D. R.; Turk, P. J.; Mnatsakanov, R.; Lynch, R. S.; Ransom, S. M.; Freire, P. C.; Belczynski, K. (November 2011), ”Young Radio Pulsars in Galactic Globular Clusters”, The Astrophysical Journal 742 (1): 51, doi:, Bibcode: 2011ApJ...742...51B.
- ^ Forbes, Duncan A.; Bridges, Terry (May 2010), ”Accreted versus in situ Milky Way globular clusters”, Monthly Notices of the Royal Astronomical Society 404 (3): 1203–1214, doi:, Bibcode: 2010MNRAS.404.1203F.
Externa länkar
Wikimedia Commons har media som rör Messier 80.- SEDS informerar om Messier 80
- Messier 80, Galactic Globular Clusters Database page
- Messier 80 at ESA/Hubble
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Media som används på denna webbplats
This stellar swarm is M80 (NGC 6093), one of the densest of the 147 known globular star clusters in the Milky Way galaxy. Located about 28,000 light-years from Earth, M80 contains hundreds of thousands of stars, all held together by their mutual gravitational attraction. Globular clusters are particularly useful for studying stellar evolution, since all of the stars in the cluster have the same age (about 12 billion years), but cover a range of stellar masses. Every star visible in this image is either more highly evolved than, or in a few rare cases more massive than, our own Sun. Especially obvious are the bright red giants, which are stars similar to the Sun in mass that are nearing the ends of their lives.
A rich collection of colourful astronomical objects is revealed in this picturesque image of the Rho Ophiuchi cloud complex from NASA’s Wide-field Infrared Explorer, or WISE. The Rho Ophiuchi cloud (pronounced ‘oh-fee-yoo-ki’ and named after a bright star in the region) is found rising north of the plane of the Milky Way in the night sky, bordering the constellations Ophiuchus and Scorpius. It’s one of the nearest star-forming regions to Earth, allowing us to resolve much more detail than in more distant similar regions, like the Orion nebula.
The amazing variety of different colours seen in this image represents different wavelengths of infrared light. The bright white nebula in the centre of the image (IC 4603) is glowing due to heating from nearby stars, resulting in what is called an emission nebula. The same is true for most of the multi-hued gas prevalent throughout the entire image, including the bluish bow-shaped feature near the bottom right. The bright red area in the bottom right is light from the star in the centre – Sigma Scorpii – that is reflected off of the dust surrounding it, creating what is called a reflection nebula. And the much darker areas scattered throughout the image are pockets of cool dense gas that block out the background light, resulting in absorption (or ‘dark’) nebulae. WISE’s longer wavelength detectors can typically see through dark nebulae, but these are exceptionally opaque.
The bright pink objects just left of centre are young stellar objects (YSOs). These baby stars are just now forming; many of them are still enveloped in their own tiny compact nebulae. In visible light, these YSOs are completely hidden in the dark nebula that surrounds them, which is sometimes referred to as their baby blanket. We can also see some of the oldest stars in our Milky Way Galaxy in this image, found in two separate (and much more distant) globular clusters. The first cluster, M80, is on the far right edge of the image towards the top. The second, NGC 6144, is found close to the bottom edge near the centre. They both appear as small densely compacted groups of blue stars. Globular clusters such as these typically harbour some of the oldest stars known, some as old as 13 billion years, born soon after the Universe formed.
There are two other items of interest in this image as well. At the 3 o’clock position, relative to the bright central region, and about two-thirds of the way from the centre to the edge, there is a small faint red dot. That dot is an entire galaxy far, far away known as PGC 090239. And, at the bottom left of the image, there are two lines emerging from the edge. These were not created by foreground satellites; they are diffraction spikes (optical artefacts from the space telescope) from the bright star Antares that is just out of the field of view.
Position of object (J2000): RA = 16h 25m 17s; Dec = -24° 14’ 49”
Constellation: Ophiucus and Scorpius
Field of View: 1.967x1.948 degrees
The picture covers approximately Declination -22° to -26.1° and Right Ascension 16h17m to 16h37m.
Orientation: North is 0.12966 degrees left of up
Color Mapping: Blue=3.4 microns; Cyan=4.6 microns; Green=12 microns; Red=22 microns