Astronomers discovered 7 earth-sized planets orbiting nearby star

Astronomers have discovered seven earth-sized planets orbiting same star which is 40 light-years away according to a study published on wednesday ( 22nd Feb 2017) in the journal of nature.  The discovery was announced at a news conference at NASA headquarters in Washington.  

This discovery which is outside of our solar system is a rare event because the planets have the winning combination of being similar to the size of Earth and being all temperate, meaning they could have water on their surfaces and potentially support life..

The seven planets were all found in a tight formation around an ultra cool dwarf star called TRAPPIST-1.  Some estimates indicate that they are rocky planets rather than being gaseous like Jupiter.   Three planets are in habitable zone of the star and may even have oceans on their surfaces.  These three planets are called as Trappist-1e, 1f and 1g.

The researchers believe that Trappist-1f is the best candidate for supporting life. It is little bit cooler than Earth but can be suitable with the right atmosphere and enough green house gases.

These planets are very close to each other and the star.   They are all within five times within a space five times smaller than the distance from Mercury to our Sun.  This proximity allows the researchers to make a study of the planets in depth as well, gaining insight about planetary systems other than our own.  The seven planets of Trappist-1 are compared with Mercury, Venus, Earth and Mars.

As we move away from the closest to the star to outwards,  the planets have respective orbits from one and half to nearly 13 Earth days.  The orbit of the farthest planet is still not known.   If you stand on surface of one of the planets, you would receive 200 times less light than you get from the Sun, but you would still receive just as much energy to keep you warm since the star is so close..   It would also afford some views, as the other planets would appear in the sky as big as the moon. 

If you stand on Trappist-1f,  the star would appear three times as big as the sun in our sky.  The researchers believe that because of red nature of the star, the light would be a salmon hue.  The researchers believe that the planets were formed together further from the star.  Then they would have moved into their current lineup.   Like our moon,  the researchers believe that the planets closest to the star are tidally locked.  This means that the planets always face one side to the star.  One side of the planet is night and other side always day;.

As per preliminary studies on climate,  the researchers believe that the three planets which are closest to the star may be too warm to support liquid water, while the outermost planet, Trappist-1h, is probably too distant and cold to support water on the surface.

Trappist-1 is a star which is half the temperature and a tenth of the mass of the Sun.  It is red, dim and just a bit larger than Jupiter.  But these tiny ultra cool stars are common in our galaxy.  By using a global network ground-based telescopes like TRAPPIST and space-based telescopes like Spitzer, the researchers continued looking toward the Trappist system and were able to determine the  orbits and orbital periods and distances of the planets from the star, their radius and their masses.  

The researchers are planning to define the atmosphere of each planet as well as determine whether they truly do have liquid water on their surface and search for life on these planets.  All this would happen in the next decade.  Even though 40 light years is not too distant, but it would take us millions of years to reach this star system.  But for research purpose, it is a close opportunity and the best target to search for life beyond our solar system.

James Webb Space Telescope will be launched i 2018 and positioned at a distance of 1 million miles from Earth with a view of the Universe.  It can observe large exoplanets and detect starlight filtered through their atmosphere.. They are also searching for similar star systems to conduct atmosphere research.  Four telescopes named SPECULOOS ( Search for habitable planets EClipsing ULtra-cOOl Stars) based in Chile will survey the southern sky for this purpose.  

This star system will probably outlive us because this type of star evolves so slowly.  When out Sun dies, TRAPPIST-1 will still be young star and will live for another trillion years.   After we are all gone, if there is another part of the Universe for life to carry on,  it may be in the TRAPPIST-1 system.

Newly discovered Jupiter twin hints of a new solar system to our solar system

A group of astronomers used ESO 3.6 meter telescope to identify a planet similar to our Jupiter orbiting a Sun-like star at the same distance similar to our Jupiter from Sun.  The star name is HIP-11915.

As per the present theories, the formation of Jupiter like heavy mass planets play an important role in shaping the architecture of planetary systems.   The existence of a Jupiter like planet in a Jupiter-like orbit around a Sun-like star opens up the possibility of a system of planets around that star may be similar to our Solar System.   The Star HIP 11915 is about the same age as our Sun and its composition is similar to Sun which suggests that there may be rocky planets orbiting around that star.

As per the most recent theories, the arrangement of our Solar System, so supportive to life, was made possible due to the presence of Jupiter and the gravitational influence of this gas giant exerted on our Solar System during the formative years.  There fore it would seem that finding a Jupiter twin is an important milestone in finding a planetary system similar to our own Solar System.

The Jupiter twin is 200 light years from our Earth.  The image below shows an artist's impression of the Jupiter twin orbiting around the Sun like star..

NASA's Hubble Telescope finds signs of water on 5 alien planets

NASA's Hubble Telescope has detected water in the atmospheres of five alien planets which are beyond our solar system.   

These five planets are Jupiter size planets which are very hot and unlikely to host life.  But this finding of water in other extra solar planets marks a step forward in search of distant planets which may be capable of supporting life.

 Two research teams of NASA used the wide field camera 3 of Hubble to analyze starlight passing through the atmospheres of five hot Jupiter like planets which are known as
WASP-17b, HD209458b, WASP-12b, WASP-19b and XO-1b.  The atmospheres of all the five planets showed the signs of water with the strongest signs found in the air of
WASP-17b and HD209458b..

Astronomers discover new planets, 3 of which are habitable

Astronomers  have discovered a new solar system which contains planets.  Three of those planets are suitable for living.   These three planets are habitable - means in the zone around the star where liquid water could exist which makes them possible candidates for presence of life.

The star named Gliese 667C is orbited by 7 planets and is a part of a triple star system known as Gliese 667.   "We identified three strong signals in the star before, but it was possible that smaller planets were hidden in the data," said Guillem Anglada-Escudé of the University of Göttingen in Germany, who led the study. "We reexamined the existing data, added some new observations, and applied two different data analysis methods especially designed to deal with multi-planet signal detection."

"Both methods yielded the same answer: There are five very secure signals and up to seven low-mass planets in short-period orbits around the star."    The Gliese 667C solar system is strikingly similar to ours and the three planets identified as habitable are confirmed to be super-Earths: planets that have more mass than Earth but less mass than larger planets like Uranus and Neptune.

The star is 22 light-years away from earth and is located in the constellation of Scorpius which is very close to our solar system, astronomers said -- within the Sun’s neighborhood, so to speak -- and much closer than the star systems investigated using telescopes such as the planet-hunting Kepler space telescope.


"This is the first time that three such planets have been spotted orbiting in this zone in the same system," astronomer Paul Butler of the Carnegie Institute for Science who participated in the study said.  

Similar systems have been found before and are very common in the Milky Way, however, most of these systems are built around Sun-like stars and are too hot to be habitable.
The Gliese 667C system is the first example of a system that contains multiple habitable planets surrounding a low-mass star.

The discovery of more systems like Gliese 667C could mean that the amount of potentially habitable planets in our galaxy are more numerous than believed.