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Showing posts with label exoplanet. Show all posts
Showing posts with label exoplanet. Show all posts

Saturday 7 March 2015

Massive Exoplanet Evolved in Extreme 4-Star System

According to a team of astronomers headed by Dr Lewis Roberts from NASA’s Jet Propulsion Laboratory in Pasadena, an extrasolar gas giant called 30 Arietis Bb (30 Ari Bb) is the second known example of a planet residing in a system with four stars.

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Artists conception of the 30 Ari star system. In the foreground is the primary star about which the massive exoplanet orbits. The primary's newly-found binary partner, a red dwarf, can be seen in the upper left and the secondary binary system can be seen to the upper right.

While 30 Ari Bb was known before, it was thought to reside in a system of three stars, not four.

The system, called 30 Ari, is located in the constellation Aries, approximately 136 light-years away.

“Star systems come in myriad forms. There can be single stars, binary stars, triple stars, even quintuple star systems. It’s amazing the way nature puts these things together,” Dr Roberts said.

The planet itself is enormous, with 9.88 times the mass of Jupiter. It orbits its primary star, 30 Ari B, every 335 days. This star has a relatively close partner star, which the planet does not orbit.

The pair, in turn, is locked in a long-distance orbit with another pair of stars about 1,670 AU away.

“It’s highly unlikely that this planet, or any moons that might circle it, could sustain life,” Dr Roberts and his colleagues said.

The first four-star planet, Ph1b, was discovered in the star system Kepler-64 (KIC 4862625) in 2013 by astronomers using data from NASA’s Kepler mission.

The latest discovery, reported in the Astronomical Journal (arXiv.org preprint), suggests that exoplanets in quadruple star systems might be less rare than once thought.

The similarity between Kepler-64 and 30 Ari is that both systems are quadruples consisting of two relatively close pairs that are widely separated.

In fact, recent studies have shown that this type of star systems is itself more common than previously believed.

“About 4% of Sun-like stars are in quadruple systems, which is up from previous estimates because observational techniques are steadily improving,” said team member Dr Andrei Tokovinin of the Cerro Tololo Inter-American Observatory in Chile.

The scientists also reported on a triple-star planetary system, HD 2638, which hosts a so-called hot-Jupiter.

This giant planet, named HD 2638b, orbits its primary star tightly, completing one lap every 3 days.

Source : sci-news.com

Thursday 29 January 2015

Planets orbiting Kepler 444 suggest there’s ancient life in the Milky Way

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NASA’s exoplanet hunting Kepler space telescope has encountered a few problems as of late, but there’s still a mountain of data for astronomers to dig through from the last four years. Astronomers analyzing Kepler data recently uncovered something unusual — a solar system about 117 light years away in the direction of Lyra called Kepler-444 with at least five Earth-sized planets. That would be unusual enough, but this planetary system is also extraordinarily ancient at roughly 11.2 billion years.
Astronomers are intrigued by this discovery for several reasons. First, that’s a lot of small rocky planets. Kepler detects alien worlds by the transit method. It watches distant suns for slight dips in brightness that indicate a planet has passed between it and the telescope. These events can be used to calculate the characteristics of the planet, but it works best for larger worlds (super Earths and gas giants). Spotting five planets between the size of Mercury and Venus (basically a little smaller than Earth) is unusual.

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Artistic Depiction of Kepler 444 with its Star
 The age of Kepler-444 is also something to note. At 11.2 billion years old, the planets orbiting this star were already older than Earth is now when our sun ignited 4.5 billion years ago. The universe itself is only 13.8 billion or so years old, making Kepler-444 one of the oldest stars in the Milky Way. It would have been from the first generation of stars that dotted the sky. Kepler-444 is still very sun-like because it’s 25% smaller and cooler. That means it burns through its nuclear fuel more slowly.
Finding small rocky planets that are billions of years older than Earth suggests that advanced life may have existed in the universe for a very long time. Life on Earth might be very new by comparison. Just think, planets similar to Earth were forming more than 7 billion years before Earth formed, and some of them could have supported life. If other first-generation stars like Kepler-444 have planets, uncountable civilizations could have come into being eons before the first single-cell life appeared on Earth.
The planets orbiting Kepler-444 themselves are not able to support life as we know it. All five planets are packed very close to the parent star with orbits closer than that of Mercury in our solar system. With solar years less than 10 Earth days, they definitely stood out in the Kepler data. The surfaces of these worlds have been baked by the intense heat, reducing any organic material to cinders.
Kepler-444 isn’t a bastion of alien life, but it improves our understanding of planetary formation and points us in a new direction. Astronomers are anxious to find other ancient stars with rocky planets in hopes they might prove more hospitable to life. What if there was still something alive on one of these ancient worlds? That might sound like science fiction right now, but maybe it won’t always be — there’s still a lot of data from Kepler, and future telescopes will improve our ability to spy distant exoplanets.
 Source: Geek.com

Tuesday 27 January 2015

Scientists Discover Exoplanet With Rings Far More Impressive Than Our Saturn

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Artist’s conception of the extrasolar ring system circling the young giant planet or brown dwarf J1407b is shown. Credit: Ron Miller

Children and adults alike marvel at the rings around Saturn. In a model of our solar system, Saturn—and its rings—is typically the one that gets the most attention.

But while it is easy to be fascinated by Saturn, astronomers have recently found an exoplanet with an even grander expanse of wings that is sure to wow a new generation of stargazers.

“The star is much too far away to observe the rings directly, but we could make a detailed mode based on the rapid brightness variations in the star light passing through the ring system. If we could replace Saturn’s rings with the rings around J1407b, they would be easily visible at night and be many times larger than the full moon,” explains lead researcher Matthew Kenworthy. “The details that we see in the light curve are incredible. The eclipse lasted for several weeks, but you see rapid changes on time scales of tens of minutes as a result of fine structures in the rings.”

Study co-author Eric Mamaek, who first found the rings of the planet, comments, “The planetary science community has theorized for decades that planets like Jupiter and Saturn would have had, at an early stage, disks around them that then led to the formation of satellites. However, until we discovered this object in 2012, no-one had seen such a ring system. This is the first snapshot of satellite formation on million-kilometer scales around a substellar object.”

The University of Rochester professor of physics and astronomy goes on to say, “This planet is much larger than Jupiter or Saturn, and its ring system is roughly 200 times larger than Saturn’s rings are today. You could think of it as a kind of super Saturn.”

Source : piercepioneer.com

Sunday 18 January 2015

Researchers: Solar system may have Planet X , Planet Y

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The presence of two additional planets might explain the unexpected orbital features of some trans-Neptunian objects.

Scientists have postulated the existence of possibly two undiscovered planets beyond the orbit of Neptune to explain discrepancies in the orbits of extreme trans-Neptunian objects (ETNO). The objects have orbits that take them beyond the orbit of the planet Neptune.

Theory predicts that they be randomly distributed and that their orbits must have a semi-major axis with a value around 150 AU; an orbital inclination of nearly zero degrees; and an angle of perihelion, the point in the object’s orbit at which it is closest to the Sun, of zero to 180 degrees.

However, a dozen ETNO do not fit these orbital criteria. These objects have semi-major axis values of 150 to 525 AU, orbital inclinations of around 20 degrees, and angles of perihelion far from 180 degrees.

According to a statement, a new study by astrophysicists at the Complutense University of Madrid (UCM) and University of Cambridge have calculated that these orbital discrepancies could be explained by the existence of at least two additional planets beyond the orbits of Neptune and dwarf planet Pluto. Their study suggests that the gravitational pulls of those two planets must be disturbing the orbits of some smaller ETNO.

However, there are two difficulties with the hypothesis. One is that current models of the formation of our solar system do not allow for additional planets beyond Neptune. Secondly, the team’s sample size is very small, only 13 objects. However, additional results are in the pipeline, which will expand the sample.

“This excess of objects with unexpected orbital parameters makes us believe that some invisible forces are altering the distribution of the orbital elements of the ETNO and we consider that the most probable explanation is that other unknown planets exist beyond Neptune and Pluto,” said Carlos de la Fuente Marcos of UCM and lead author on the study.

The new findings have been published in two papers published in the journal Monthly Notices of the Royal Astronomical Society Letters.

Source : thespacereporter

Friday 14 November 2014

A Universe of Blue Dots? --"Water Common During the Formation of All Planetary Systems"

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The new SciFi blockbuster, Interstellar, shows astonauts from post apocalyptic earth, destroyed by what appears to be a modern dust-bowl, catapulted into the unknown of outer space in the hopes of finding a new home for the human race, only to discover an extraterrestrial tidal wave on a distant exo planet. How realistic is the premise of an alien water planet? New findings suggest it's based on solid science.
"This is an important step forward in our quest to find out if life exists on other planets," said Tim Harries, from the University of Exeter's Physics and Astronomy department, who was part of the research team. "We know that water is vital for the evolution of life on Earth, but it was possible that the Earth's water originated in the specific conditions of the early solar system, and that those circumstances might occur infrequently elsewhere. By identifying the ancient heritage of Earth's water, we can see that the way in which our solar system was formed will not be unique, and that exoplanets will form in environments with abundant water. Consequently, it raises the possibility that some exoplanets could house the right conditions, and water resources, for life to evolve."
The implication of these findings is that some of the solar system's water must have been inherited from the Sun's birth environment, and thus predate the Sun itself. If our solar system's formation was typical, this implies that water is a common ingredient during the formation of all planetary systems.

To date, the Kepler satellite has detected nearly 1,000 confirmed extrasolar planets. The widespread availability of water during the planet-formation process puts a promising outlook on the prevalence of life throughout the galaxy.

A pioneering new study has shown that water found on Earth predates the formation of the Sun – raising hopes that life could exist on exoplanets, the planets orbiting other stars in our galaxy. The ground-breaking research set out to discover the origin of the water that was deposited on the Earth as it formed.

It found that a significant fraction of water found on Earth, and across our solar system, predates the formation of the Sun. By showing that water is 'inherited' from the environment when a star is born, the international team of scientists believe other exoplanetary systems also had access to an abundance of water during their own formation.

As water is a key component for the development of life on Earth, the study has important implications for the potential for life elsewhere in the galaxy.

Scientists have previously been able to understand the conditions present when stars are formed by looking at the composition of comets and asteroids, which show which gases, dust and, most importantly, ices were circling the star at its birth.

The team of international scientists were able to use 'heavy water' ices – those with an excess of water made with the element deuterium rather than hydrogen – to determine whether the water ices formed before, or during, the solar system's formation.

Saturday 1 November 2014

"Unexpected Planet" Discovered by Yale Astronomers

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Astronomers have discovered a new planet that has a highly inconsistent orbit time around its Sun.

The low-mass, low-density planet, known only as PH3c, which is 2,300 light years away from the Earth, has an atmosphere loaded with hydrogen and helium.

The planet nearly escaped detection as PH3c does not have a consistent orbit time around its Sun due to the gravitational influence of other planets on its system.

“On the Earth, these effects are very small, only on the scale of one second or so,” said Joseph Schmitt, a graduate student at Yale University.

“PH3c’s orbital period changed by 10.5 hours in just 10 orbits,” explained Schmitt.

This inconsistency kept the planet out of reach for automated computer algorithms that search stellar light curves and identify regular dips caused by objects passing in front of stars, he said.

The researchers discovered the new planet with the help of Planet Hunters programme coordinated by Yale University and University of Oxford.

The programme, which has found over 60 planet candidates since 2010, enlists citizen scientists to check survey data from the Kepler spacecraft.

Not only did Planet Hunters spot PH3c, but the discovery also enabled astronomers to better characterise two other planets - one on each side of PH3c.

An outer planet PH3d is slightly larger and heavier than Saturn. An inner planet, PH3b may have a rocky composition like the Earth.

“Finding the middle planet was key to confirming the others and allowing us to find their masses,” Schmitt explained.