NGC 602a, the 'Tip of the 'Wing'
04.03.13
Astronomers call all elements heavier than hydrogen and helium -- that
is, with more than two protons in the atom's nucleus -- "metals." The
Wing is a region known to have fewer metals compared to most areas
within the Milky Way. There are also relatively lower amounts of gas,
dust, and stars in the Wing compared to the Milky Way.
Taken together, these properties make the Wing an excellent location to study the life cycle of stars and the gas lying in between them. Not only are these conditions typical for dwarf irregular galaxies like the SMC, they also mimic ones that would have existed in the early Universe.
Most star formation near the tip of the Wing is occurring in a small region known as NGC 602, which contains a collection of at least three star clusters. One of them, NGC 602a, is similar in age, mass, and size to the famous Orion Nebula Cluster. Researchers have studied NGC 602a to see if young stars -- that is, those only a few million years old -- have different properties when they have low levels of metals, like the ones found in NGC 602a.
Using Chandra, astronomers discovered extended X-ray emission, from the two most densely populated regions in NGC 602a. The extended X-ray cloud likely comes from the population of young, low-mass stars in the cluster, which have previously been picked out by infrared and optical surveys, using Spitzer and Hubble respectively. This emission is not likely to be hot gas blown away by massive stars, because the low metal content of stars in NGC 602a implies that these stars should have weak winds. The failure to detect X-ray emission from the most massive star in NGC 602a supports this conclusion, because X-ray emission is an indicator of the strength of winds from massive stars. No individual low-mass stars are detected, but the overlapping emission from several thousand stars is bright enough to be observed.
The Chandra results imply that the young, metal-poor stars in NGC 602a produce X-rays in a manner similar to stars with much higher metal content found in the Orion cluster in our galaxy. The authors speculate that if the X-ray properties of young stars are similar in different environments, then other related properties -- including the formation and evolution of disks where planets form -- are also likely to be similar.
X-ray emission traces the magnetic activity of young stars and is related to how efficiently their magnetic dynamo operates. Magnetic dynamos generate magnetic fields in stars through a process involving the star's speed of rotation, and convection, the rising and falling of hot gas in the star's interior.
The combined X-ray, optical and infrared data also revealed, for the first time outside our Galaxy, objects representative of an even younger stage of evolution of a star. These so-called "young stellar objects" have ages of a few thousand years and are still embedded in the pillar of dust and gas from which stars form, as in the famous "Pillars of Creation" of the Eagle Nebula.
A paper describing these results was published online and in the March 1, 2013 issue of The Astrophysical Journal. The first author is Lidia Oskinova from the University of Potsdam in Germany and the co-authors are Wei Sun from Nanjing University, China; Chris Evans from the Royal Observatory Edinburgh, UK; Vincent Henault-Brunet from University of Edinburgh, UK; You-Hua Chu from the University of Illinois, Urbana, IL; John Gallagher III from the University of Wisconsin-Madison, Madison, WI; Martin Guerrero from the Instituto de Astrofísica de Andalucía, Spain; Robert Gruendl from the University of Illinois, Urbana, IL; Manuel Gudel from the University of Vienna, Austria; Sergey Silich from the Instituto Nacional de Astrofısica Optica y Electr´onica, Puebla, Mexico; Yang Chen from Nanjing University, China; Yael Naze from Universite de Liege, Liege, Belgium; Rainer Hainich from the University of Potsdam, Germany, and Jorge Reyes-Iturbide from the Universidade Estadual de Santa Cruz, Ilheus, Brazil.
Credits: X-ray: NASA/CXC/Univ.Potsdam/L.Oskinova et al; Optical: NASA/STScI; Infrared: NASA/JPL-Caltech
› Read more/access all images
› Chandra's Flickr photoset
Taken together, these properties make the Wing an excellent location to study the life cycle of stars and the gas lying in between them. Not only are these conditions typical for dwarf irregular galaxies like the SMC, they also mimic ones that would have existed in the early Universe.
Most star formation near the tip of the Wing is occurring in a small region known as NGC 602, which contains a collection of at least three star clusters. One of them, NGC 602a, is similar in age, mass, and size to the famous Orion Nebula Cluster. Researchers have studied NGC 602a to see if young stars -- that is, those only a few million years old -- have different properties when they have low levels of metals, like the ones found in NGC 602a.
Using Chandra, astronomers discovered extended X-ray emission, from the two most densely populated regions in NGC 602a. The extended X-ray cloud likely comes from the population of young, low-mass stars in the cluster, which have previously been picked out by infrared and optical surveys, using Spitzer and Hubble respectively. This emission is not likely to be hot gas blown away by massive stars, because the low metal content of stars in NGC 602a implies that these stars should have weak winds. The failure to detect X-ray emission from the most massive star in NGC 602a supports this conclusion, because X-ray emission is an indicator of the strength of winds from massive stars. No individual low-mass stars are detected, but the overlapping emission from several thousand stars is bright enough to be observed.
The Chandra results imply that the young, metal-poor stars in NGC 602a produce X-rays in a manner similar to stars with much higher metal content found in the Orion cluster in our galaxy. The authors speculate that if the X-ray properties of young stars are similar in different environments, then other related properties -- including the formation and evolution of disks where planets form -- are also likely to be similar.
X-ray emission traces the magnetic activity of young stars and is related to how efficiently their magnetic dynamo operates. Magnetic dynamos generate magnetic fields in stars through a process involving the star's speed of rotation, and convection, the rising and falling of hot gas in the star's interior.
The combined X-ray, optical and infrared data also revealed, for the first time outside our Galaxy, objects representative of an even younger stage of evolution of a star. These so-called "young stellar objects" have ages of a few thousand years and are still embedded in the pillar of dust and gas from which stars form, as in the famous "Pillars of Creation" of the Eagle Nebula.
A paper describing these results was published online and in the March 1, 2013 issue of The Astrophysical Journal. The first author is Lidia Oskinova from the University of Potsdam in Germany and the co-authors are Wei Sun from Nanjing University, China; Chris Evans from the Royal Observatory Edinburgh, UK; Vincent Henault-Brunet from University of Edinburgh, UK; You-Hua Chu from the University of Illinois, Urbana, IL; John Gallagher III from the University of Wisconsin-Madison, Madison, WI; Martin Guerrero from the Instituto de Astrofísica de Andalucía, Spain; Robert Gruendl from the University of Illinois, Urbana, IL; Manuel Gudel from the University of Vienna, Austria; Sergey Silich from the Instituto Nacional de Astrofısica Optica y Electr´onica, Puebla, Mexico; Yang Chen from Nanjing University, China; Yael Naze from Universite de Liege, Liege, Belgium; Rainer Hainich from the University of Potsdam, Germany, and Jorge Reyes-Iturbide from the Universidade Estadual de Santa Cruz, Ilheus, Brazil.
Credits: X-ray: NASA/CXC/Univ.Potsdam/L.Oskinova et al; Optical: NASA/STScI; Infrared: NASA/JPL-Caltech
› Read more/access all images
› Chandra's Flickr photoset
J.D. Harrington, 202-358-0321
Headquarters, Washington
j.d.harrington@nasa.gov
Janet Anderson, 256-544-0034
Marshall Space Flight Center, Huntsville, Ala.
janet.l.anderson@nasa.gov
Megan Watzke 617-496-7998
Chandra X-ray Center, Cambridge, Mass.
mwatzke@cfa.harvard.edu
Headquarters, Washington
j.d.harrington@nasa.gov
Janet Anderson, 256-544-0034
Marshall Space Flight Center, Huntsville, Ala.
janet.l.anderson@nasa.gov
Megan Watzke 617-496-7998
Chandra X-ray Center, Cambridge, Mass.
mwatzke@cfa.harvard.edu
NASA
PEQUEÑA NUBE DE MAGALLANES .
La Pequeña Nube de Magallanes (denominada NGC 292 en el catálogo galáctico y a veces "SMC" del inglés Small Magellanic Cloud), es una galaxia irregular enana cercana a la Vía Láctea; se encuentra a un promedio de 200.000 años luz de distancia. Hasta el año 1994 se pensaba que orbitaba alrededor de la Vía Láctea,
pero investigaciones recientes sugieren que este no es el caso, sino
que es una galaxia espiral distorsionada al pasar cerca de la Vía
Láctea.3 4 Es uno de los objetos más lejanos visibles a simple vista. Es cien veces más pequeña que la Vía Láctea5 y por lo tanto entre 1000 y de 4000 millones de estrellas.
Está ubicada en la constelación de Tucana, a unos -72 grados de latitud celeste. Junto con la Gran Nube de Magallanes (ubicada 20 grados más al este) es una de las galaxias vecinas más cercanas a la Vía Láctea, conformando el Grupo Local con la galaxia de Andrómeda y otras cercanas.
Se especula que la Pequeña Nube de Magallanes fue alguna vez una galaxia espiral barrada, que fue distorsionada por la Vía Láctea. Todavía conserva una estructura central en forma de barra.
Debido a su baja latitud celeste, ambas Nubes de Magallanes son visibles en muchos de los países australes todas las noches (son circumpolares). Pueden ser vistas desde Hawái a 5 grados de latitud celeste desde el horizonte durante ciertas estaciones. Debido a que tiene muy poco brillo de superficie, es mejor ver la Pequeña Nube de Magallanes desde un lugar oscuro, lejos de las luces de la ciudad. La primera observación por un europeo fue documentada por Antonio Pigafetta durante el viaje de circunnavegación iniciado por Fernando de Magallanes (1519-1522).
Wikipedia.
Está ubicada en la constelación de Tucana, a unos -72 grados de latitud celeste. Junto con la Gran Nube de Magallanes (ubicada 20 grados más al este) es una de las galaxias vecinas más cercanas a la Vía Láctea, conformando el Grupo Local con la galaxia de Andrómeda y otras cercanas.
Se especula que la Pequeña Nube de Magallanes fue alguna vez una galaxia espiral barrada, que fue distorsionada por la Vía Láctea. Todavía conserva una estructura central en forma de barra.
Debido a su baja latitud celeste, ambas Nubes de Magallanes son visibles en muchos de los países australes todas las noches (son circumpolares). Pueden ser vistas desde Hawái a 5 grados de latitud celeste desde el horizonte durante ciertas estaciones. Debido a que tiene muy poco brillo de superficie, es mejor ver la Pequeña Nube de Magallanes desde un lugar oscuro, lejos de las luces de la ciudad. La primera observación por un europeo fue documentada por Antonio Pigafetta durante el viaje de circunnavegación iniciado por Fernando de Magallanes (1519-1522).
Wikipedia.
Guillermo Gonzalo Sánchez Achutegui
ayabaca@gmail.com
ayabaca@hotmail.com
ayabaca@yahoo.com
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