کشف یک سیاره بیگانه با ابعادی ۱۱ برابر بزرگتر از مشتری

HD-106906

سیاره‌ای غول‌پیکر، با ابعادی ۱۱ برابر سیاره مشتری تحت عنوان ۶۰۹۶۰۱HD در دورترین مدار شناسایی شده در اطراف یک ستاره کشف شد. دانشمندان و ستاره‌شناسان ناسا بر این باورند که  سیاره جدید در فاصله ای ۶۵۰ برابر مسافت زمین تا خورشید در حال چرخش است. برای مقایسه این فاصله ۲۰ برابر دورتر از مدار نپتون تا خورشید میباشد. تمامی سیاره‌های موجود در منظومه خورشیدی در برابر آن ذره‌ای کوچک به نظر می آیند. کشف چنین جرم عظیم و دورافتاده‌ای سوالاتی جدید را درباره چگونگی شکل‌گیری این سیاره‌ها برانگیخته است.

ونسا بیلی از کارشناسان تیم تحقیقاتی دانشکده نجوم دانشگاه آریزونای امریکا در گفت‌وگو با خبرنگاران محلی اعلام کرد: سیاره جدید دارای ویژگی‌های کاملاً منحصر به فرد و خاصی است. طبق فرضیه‌های موجود ابر سیارات در مسافتی بسیار دورتر از ستاره‌ خودشان در چرخش هستند و از طریق شیوه‌ای مشابه سیستم‌های ستاره‌های دو تایی شکل می‌گیرند. کشف سیاره جدید حقایق نجومی و نظریه‌های کاملاً متفاوتی را به وجود آورده است. ستاره‌شناسان ناسا بر این باورند با آزمایش‌های فراوان به اسرار وجود این سیارات پی ببرند. اغلب نظریه‌های تایید شده درباره نحوه شکل‌گیری و پیدایش سیارات، آنان را به صورت اجرامی کوچک و احاطه شده در گاز و گرد وغبار اطراف ستاره تعریف کرده‌اند.

HD-106906

به گفته دانشمندان سیاره ۶۰۹۶۰۱HD در حدود ۱۳ میلیون سال سن دارد و بر اثر گرمای موجود از زمان پیدایش خود، در حال درخشش است. از این رو محققان احتمال می‌دهند که شاید سیاره‌های غول‌پیکر به شیوه‌ای مشابه با سیستم‌های ستاره‌ای دوتایی متولد می‌شوند. این سیستم‌ها زمانی متولد می‌شوند که دو توده گازی مشابه به صورت جداگانه متلاشی می‌شوند و ستاره‌هایی را به وجود می‌آورند و این ستاره‌ها به اندازه‌ای به یکدیگر نزدیکند که می‌توانند کشش گرانشی دوجانبه‌ای را به یکدیگر وارد آورده و دو ستاره در مدار یکدیگر قفل می‌شوند. این سیاره توسط محققان  تلسکوپ ماژلان در شیلی کشف و با تلکسوپ فضایی‌هابل تایید شد.

منبع : space

 

Giant Alien Planet Discovered in Most Distant Orbit Ever Seen

An enormous alien planet — one that is 11 times more massive than Jupiter — was discovered in the most distant orbit yet found around a single parent star.

The newfound exoplanet, dubbed HD 106906 b, dwarfs any planetary body in the solar system, and circles its star at a distance that is 650 times the average distance between the Earth and the sun. The existence of such a massive and distantly orbiting planet raises new questions about how these bizarre worlds are formed, the researchers said.

"This system is especially fascinating because no model of either planet or star formation fully explains what we see," study lead researcher Vanessa Bailey, a fifth-year graduate student in the University of Arizona's department of astronomy, said in a statement.

In the most commonly accepted theories of planet formation, it is thought that planets that orbit close to their parent star, such as Earth, began as small, asteroid-type bodies that clumped together in the primordial disk of gas and dust around the burgeoning star. Yet, this process operates too slowly to explain how giant planets form far away from their star, the researcher said.

Alternative hypotheses have suggested that distant giant planets may form in ways similar to mini binary star systems, Bailey said.

"A binary star system can be formed when two adjacent clumps of gas collapse more or less independently to form stars, and these stars are close enough to each other to exert a mutual gravitation attraction and bind them together in an orbit," she explained.

In the HD 106906 system, the star and planet may have collapsed independently, but the materials that clumped together to form the planet were insufficient for it to grow large enough to ignite into a new star, Bailey said.

But, there are still problems with this scenario. For one, difference between the masses of two stars in a binary system is typically no more than a ratio of 10 to 1.

"In our case, the mass ratio is more than 100-to-1," Bailey said. "This extreme mass ratio is not predicted from binary star formation theories — just like planet formation theory predicts that we cannot form planets so far from the host star."

Researchers are also keen to study the new planet, because leftover material from when the planet and star formed can still be detected.

"Systems like this one, where we have additional information about the environment in which the planet resides, have the potential to help us disentangle the various formation models," Bailey said. "Future observations of the planet's orbital motion and the primary star's debris disk may help answer that question."

Giant Alien Planet Discovered in Most Distant Orbit Ever Seen
By Denise Chow, Staff Writer   |   December 06, 2013 10:20am ET
Exoplanet HD 106906 b
[Pin It] An artist's conception of a young planet in a distant orbit around its host star. The star still harbors a debris disk, remnant material from star and planet formation, interior to the planet's orbit.
Credit: NASA/JPL-Caltech
View full size image

An enormous alien planet — one that is 11 times more massive than Jupiter — was discovered in the most distant orbit yet found around a single parent star.

The newfound exoplanet, dubbed HD 106906 b, dwarfs any planetary body in the solar system, and circles its star at a distance that is 650 times the average distance between the Earth and the sun. The existence of such a massive and distantly orbiting planet raises new questions about how these bizarre worlds are formed, the researchers said.

"This system is especially fascinating because no model of either planet or star formation fully explains what we see," study lead researcher Vanessa Bailey, a fifth-year graduate student in the University of Arizona's department of astronomy, said in a statement. [The Strangest Alien Planets (Gallery)]

HD 106906 System
[Pin It] This is a discovery image of planet HD 106906 b in thermal infrared light. The planet is more than 20 times farther away from its star than Neptune is from the sun.
Credit: Vanessa Bailey
View full size image

In the most commonly accepted theories of planet formation, it is thought that planets that orbit close to their parent star, such as Earth, began as small, asteroid-type bodies that clumped together in the primordial disk of gas and dust around the burgeoning star. Yet, this process operates too slowly to explain how giant planets form far away from their star, the researcher said.

Alternative hypotheses have suggested that distant giant planets may form in ways similar to mini binary star systems, Bailey said.

"A binary star system can be formed when two adjacent clumps of gas collapse more or less independently to form stars, and these stars are close enough to each other to exert a mutual gravitation attraction and bind them together in an orbit," she explained.

In the HD 106906 system, the star and planet may have collapsed independently, but the materials that clumped together to form the planet were insufficient for it to grow large enough to ignite into a new star, Bailey said.

But, there are still problems with this scenario. For one, difference between the masses of two stars in a binary system is typically no more than a ratio of 10 to 1.

"In our case, the mass ratio is more than 100-to-1," Bailey said. "This extreme mass ratio is not predicted from binary star formation theories — just like planet formation theory predicts that we cannot form planets so far from the host star."

Researchers are also keen to study the new planet, because leftover material from when the planet and star formed can still be detected.

"Systems like this one, where we have additional information about the environment in which the planet resides, have the potential to help us disentangle the various formation models," Bailey said. "Future observations of the planet's orbital motion and the primary star's debris disk may help answer that question."

Alien Planet Quiz: Are You an Exoplanet Expert?
Astronomers have confirmed more than 800 planets beyond our own solar system, and the discoveries keep rolling in. How much do you know about these exotic worlds?
Start the Quiz
Artist's conception of alien planets Kepler-36b and c
۰ of 10 questions complete

The planet HD 106906 b is only 13 million years old, and is still glowing from the residual heat from its formation," the researchers said. By comparison, Earth formed 4.5 billion years ago, which makes it roughly 350 times older than the newfound exoplanet.

The planet was found using a thermal infrared camera mounted on the Magellan telescope in the Atacama Desert in Chile. The researchers used data from the Hubble Space Telescope to confirm their discovery.

The study, which has been accepted for publication in a future issue of The Astrophysical Journal Letters, could lead to a better understanding of distantly orbiting exoplanets.

"Every new directly detected planet pushes our understanding of how and where planets can form," study co-investigator Tiffany Meshkat, a graduate student at Leiden Observatory in the Netherlands, said in a statement. "Discoveries like HD 106906 b provide us with a deeper understanding of the diversity of other planetary systems."

 

پاسخ بدهید

وارد کردن نام و ایمیل اجباری است | در سایت ثبت نام کنید یا وارد شوید و بدون وارد کردن مشخصات نظر خود را ثبت کنید *

*