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قدرت غیر عادی یک ...
#1
[تصویر:  13475209051.jpg]



In 1604, a new star appeared in the night sky that was much brighter
than Jupiter and dimmed over several weeks. This event was witnessed by
sky watchers including the famous astronomer Johannes Kepler. Centuries
later, the debris from this exploded star is known as the Kepler
supernova remnant.
Astronomers have long studied the Kepler supernova remnant and tried to
determine exactly what happened when the star exploded to create it. New
analysis of a long observation from NASA’s Chandra X-ray Observatory is
providing more clues. This analysis suggests that the supernova
explosion was not only more powerful, but might have also occurred at a
greater distance, than previously thought.




This image shows the Chandra data derived from more than eight days
worth of observing time. The X-rays are shown in five colors from lower
to higher energies: red, yellow, green, blue, and purple. These various
X-ray slices were then combined with an optical image from the Digitized
Sky Survey, showing stars in the field.




Previous analysis
of this Chandra image has determined that the stellar explosion that
created Kepler was what astronomers call a “Type Ia” supernova. This
class of supernovas occurs when a white dwarf gains mass, either by
pulling gas off a companion star or merging with another white dwarf,
until it becomes unstable and is destroyed by a thermonuclear explosion.




Unlike other well-known Type Ia supernovas and their remnants, Kepler’s
debris field is being strongly shaped by what it is running into. More
specifically, most Type Ia supernova remnants are very symmetrical, but
the Kepler remnant is asymmetrical with a bright arc of X-ray emission
in its northern region. This indicates the expanding ball of debris
from the supernova explosion is plowing into the gas and dust around the
now-dead star.




The bright X-ray arc can be explained in two ways. In one model, the
pre-supernova star and its companion were moving through the
interstellar gas and losing mass at a significant rate via a wind,
creating a bow shock wave similar to that of a boat moving through
water. Another possibility is that the X-ray arc is caused by debris
from the supernova expanding into an interstellar cloud of gradually
increasing density.




The wind and bow shock model described above requires that the Kepler
supernova remnant is located at a distance of more than 23,000 light
years. In the latter alternative, the gas into which the remnant is
expanding has higher density than average, and the distance of the
remnant from the earth is between about 16,000 and 20,000 light years.
Both alternatives give greater distances than the commonly used value of
13,000 light years.




In either model, the X-ray spectrum -- that is, the amount of X-rays
produced at different energies -- reveals the presence of a large amount
of iron, and indicates an explosion more energetic than the average
Type Ia supernova. Additionally, to explain the observed X-ray spectrum
in this model, a small cavity must have been cleared out around the star
before it exploded. Such a cavity, which would have a diameter less
than a tenth that of the remnant’s current size, might have been
produced by a fast, dense outflow from the surface of the white dwarf
before it exploded, as predicted by some models of Type Ia supernovas.




Evidence for an unusually powerful Type Ia supernova has previously been observed in another remnant
with Chandra and an optical telescope. These results were
independently verified by subsequent observations of light from the
original supernova explosion that bounced off gas clouds, a phenomenon
called light echoes. This other remnant is located in the Large
Magellanic Cloud, a small galaxy about 160,000 light years from Earth,
making it much farther away than Kepler and therefore more difficult to
study.




These results were published in the September 1st, 2012 edition of The
Astrophysical Journal. The authors of this study are Daniel Patnaude
from the Smithsonian Astrophysical Observatory in Cambridge, MA; Carles
Badenes from University of Pittsburgh in Pittsburgh, PA; Sangwook Park
from the University of Texas at Arlington, TX, and Martin Laming from
the Naval Research Laboratory in Washington DC.




NASA's Marshall Space Flight Center in Huntsville, Ala., manages the
Chandra program for NASA's Science Mission Directorate in Washington.
The Smithsonian Astrophysical Observatory controls Chandra's science and
flight operations from Cambridge, Mass.




Credits: X-ray: NASA/CXC/SAO/D.Patnaude, Optical: DSS

در مورد اظهار نظر آقایون در تاپیک دلخوری باید بگم:
آقایون: کم گوی و گزیده گوی چون در// تا ز اندک تو جهان شود پر!!!
هرچند ک کلام گوهر بار از زبان شما جاری نشده، نمیشود و نخواهد شد!!!
پاسخ
 سپاس شده توسط Behnaz ، crux ، motahare
#2
اینارو ترجمه شده بذارید

آموزش نجومتونم که.....







‫این روزها حالم خوب است
خوب ِ خوب !!
نه نشانی از دلتنگی نه روزنی از سیاهی
...و نه وسوسه ای از دل بسـتگی! ! !
. . .نوشتنم را بهانه ای نیست
...جز گفتن این که
"من"
بعد از "تو"
به هیچ "او"یی
اجازه ی "ما" شدن
نخواهم داد


پاسخ
 سپاس شده توسط amir astronomer
#3
درود بر شما
بله حق با شماست ترجمه ی این مطالب مطمئنا در این سایت مفیدتر خواهد بود اما مطلبی ک هست اینه ک فرآیند ترجمه کردن این متنها کمی زمانبر هست و تا من بخوام مطلبو ترجمه کنم و بذارم تو سایت دیگه خبر از ارزشش کم میشه و ب اصطلاح میسوزه

از همه ی علاقه مندان عذر میخوام ، آموزش نجوم هم در راه هست
در مورد اظهار نظر آقایون در تاپیک دلخوری باید بگم:
آقایون: کم گوی و گزیده گوی چون در// تا ز اندک تو جهان شود پر!!!
هرچند ک کلام گوهر بار از زبان شما جاری نشده، نمیشود و نخواهد شد!!!
پاسخ
 سپاس شده توسط mr.allahbeigi ، crux ، motahare
#4
خیلی خوب بود
بلخره اومدم :|
دلتون واسم تنگ شده بود
عخییییی d:
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