Scorpius-Centaurus Association

Scorpius-Centaurus Association

The Scorpius-Centaurus Association (sometimes called Sco-Cen) is the nearest
OB Association to the Sun. This stellar association is composed of three subgroups (Upper Scorpius,Upper Centaurus-Lupus, and Lower Centaurus-Crux), whose mean distances range from380 to 470 light years [cite journal|title=A Hipparcos Census of Nearby OB Associations|author=de Zeeuw, P.T., Hoogerwerf, R., de Bruijne, J.H.J., Brown, A.G.A., & Blaauw, A.|year=1999|journal=Astronomical Journal|volume=117|pages=354–399|url=|doi=10.1086/300682] . The Sco-Cen subgroups range in age from 5 million years (Upper Scorpius) to roughly 15 million years (Upper Centaurus-Lupus and Lower Centaurus-Crux). Many of the bright blue stars in the constellations Scorpius, Lupus, Centaurus, and Crux are members of the Sco-Cen association, including Antares (the most massive member of Upper Scorpius), and most of the stars in the Southern Cross [cite journal|title=The Nearest OB Association: Scorpius-Centaurus (Sco OB2)|author=Preibisch, T., Mamajek, E.|year=2009|journal=Handbook of Star-Forming Regions|volume=2|pages=0|url=|year=2009] . Hundreds of stars have beenidentified as members of Sco-Cen, with masses ranging from roughly 15 solar masses(Antares) down to below the hydrogen-burning limit (i.e. brown dwarfs) [cite journal| title=Exploring the Full Stellar Population of the Upper Scorpius OB Association| author=Preibisch, T., et al.|journal=Astronomical Journal|volume=124|pages=404–416|url=| doi=10.1086/341174| year=2002] ,and the total stellar population in each of the three subgroups is probablyof the order 1000-2000 [cite journal|url=
author=Mamajek, E.E., Meyer, M.R., & Liebert, J.|year=2002|journal=Astronomical Journal
volume=124|pages=1670–1694|title=Post-T Tauri Stars in the Nearest OB Association|doi=10.1086/341952
] .

The stellar members of the Sco-Cen association have convergent proper motions of approximately 0.02-0.04
arcseconds per year, indicative that the stars have nearly parallel velocity vectors, moving at about 20 km/s with respect to the Sun. The dispersion of the velocities within the subgroups are only of order 1-2 km/s [cite journal| title=Astrometric radial velocities. III. Hipparcos measurements of nearby star clusters and associations|author=Madsen, S., et al.|year=2002 |journal=Astronomy & Astrophysics|volume=381|pages=446–463|url=| doi=10.1051/0004-6361:20011458] , and the group is most likely gravitationally unbound. Several supernovae have exploded in Sco-Cenover the past 15 million years, leaving a network of expanding gas superbubbles around the group [cite journal| year=1992| url=
author=de Geus, E.J.| title=Interaction of Stars and Interstellar Matter in Scorpio Centaurus| journal=Astronomy & Astrophysics|volume=262|pages=258–270
] , including the Loop I Bubble. To explain the presence of radioactive 60Fe in deep oceanferromanganese crusts, it has been hypothesized that a nearby supernova, possiblya member of Sco-Cen, exploded in the Sun's vicinity roughly 3 million years ago [cite journal| year=2005| url=| author=Fields, B.D., Hochmuth, K.A., & Ellis, J.| title=Deep-Ocean Crusts as Telescopes: Using Live Radioisotopes to Probe Supernova Nucleosynthesis| journal=Astrophys. J.| volume=621| pages=902–907| doi=10.1086/427797] .


Wikimedia Foundation. 2010.

Игры ⚽ Поможем написать курсовую

Look at other dictionaries:

  • Scorpius-Centaurus-Assoziation — Die Scorpius Centaurus Assoziation, auch Sco Cen genannt, ist die der Sonne nächstgelegene Sternassoziation aus Sternen der Spektralklassen O und B. Wie einige andere Assoziationen heller Sterne mit einer Entfernung von unter 500 pc ist sie ein… …   Deutsch Wikipedia

  • Asociación estelar de Scorpius-Centaurus — La Asociación estelar de Scorpius Centaurus (llamada también Sco Cen) es la asociación estelar OB más cercana al Sol. Se compone de tres subgrupos (Scorpius Superior, Centaurus Superior Lupus, y Centaurus Inferior Crux), cuyas distancias medias… …   Wikipedia Español

  • Scorpius — Infobox Constellation name = Scorpius abbreviation = Sco genitive = Scorpii symbology = the Scorpion RA = 16 hrs. 53 min. 15 sec. dec= −30° 44 12 areatotal = 497 arearank = 33rd numbermainstars = 15 numberbfstars = 47 numberstarsplanets = 5… …   Wikipedia

  • Stellar association — A stellar association is a very loose star cluster, looser than both open clusters and globular clusters. Stellar associations will normally contain from 10 to 100 or more stars. The stars share a common origin, but have become gravitationally… …   Wikipedia

  • Crux — Southern Cross redirects here. For other uses, see Southern Cross (disambiguation). For other uses, see Crux (disambiguation). Crux Constellation List of stars in Crux Abbreviation C …   Wikipedia

  • Beta Pictoris — Starbox begin name=Beta PictorisStarbox image caption=Map of the Pictor constellation showing the position of Beta Pictoris.Starbox observe epoch=J2000 ra=05h 47m 17.1scite web|url=http://simbad.u id?protocol=html… …   Wikipedia

  • 1RXS J160929.1-210524 — Starbox begin name = 1RXS J160929.1 210524Starbox image caption = The star and its 8 x Jupiter mass planetary companion credit = Gemini Observatory Starbox observe epoch = J2000.0 equinox = J2000.0 constell = Scorpius ra = RA|16|09|30.3SIMBAD… …   Wikipedia

  • Stellar kinematics — is the study of the movement of stars without needing to understand how they acquired their motion. This differs from stellar dynamics, which takes into account gravitational effects. The motion of a star relative to the Sun can provide useful… …   Wikipedia

  • Nuage interstellaire local — Le Nuage interstellaire local, appelé parfois Peluche locale, est un nuage interstellaire mesurant environ 30 années lumière de large. Le système solaire s y déplace actuellement, depuis son entrée s étalant entre 40 000 à… …   Wikipédia en Français

  • Local Interstellar Cloud — The Local Interstellar Cloud, casually called the Local Fluff, is the interstellar cloud (roughly 30 light years across) through which our solar system is currently moving. The Solar System entered the Local Interstellar Cloud at some time… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”