Human’s hunt for other planetary systems like our solar system is as old as the human existence itself. Very recently, astronomers have discovered three planets or planet like objects revolving round the star HD7924. This star is just 54-light year away from our very own earth.
The Automated Planet Finder or APF set at Lick observatory and ground-telescopes in Hawii and Arizoana have made this discovery possible. It’s found that all these three planets are very close to the star and revolving round the earth in 5, 15 and 24 days respectively.
The APF facility is specially designed by the astronomers after years of research. APF is made automated by combining it with computers. The software is developed to send command to the telescopes to make them work all day and night. Thus, maximum utilization of time is made possible.
It was way back to 2009 when planetary movements around HD7924 were first observed. KECK observatory, with the help of HIRES instrument installed on 10 meter KECK I telescope, found that a super-earth like planet is revolving round the said planet. This discovery took almost 5 years. The same combination of instruments was used by astronomer Andrew Howard and Barkley university professor Geoffrey Mercy to discover super-earths revolving our neighboring stars. On the process of such observation, another two planets of HD7924 were discovered. The three planets are 7-8 times larger than the earth, hence they are termed as super-earths.
The Automatic Photometric Telescope or APT at Fairborn Observatory also contributed some crucial information regarding this discovery. Sometimes star spots mimic the presence of planets. Long term observation and analysis of data make it possible to separate star spots from planetary presence. The combination of observations by APT, APF and KECK observatory have confirmed the presence of these super-earths around the star HD7924.
NASA’s Wide Field Infrared Survey Explorer or WISE has discovered the most luminous galaxy noticed till to-date in the universe. The galaxy is noted to be emanating as much light as can be illuminated by 300 trillion suns. The galaxy is named as WISE-J224607-052635.0 may have giant black hole deep inside it. The actually emanated light energy of the galaxy is blocked by the layers of dust around the galaxy and the dust layers alternatively heated up to illuminate infrared lights. This new type of discovered galaxies are named as extremely luminous infrared galaxies or ELIRGs.
The light from the galaxy hosting the black hole has travelled 12.5 billion years to reach us. The black hole inside this galaxy is expected to be billions times the mass of the Sun. The astronomers have different opinions regarding the creation of such mammoth black holes inside ELIRGs.
Three types of opinions are available in this regard. First, they may have been born bigger, i.e. to say the seeds are much bigger than the scientists had thought previously. Second opinion is that the black hole is crossing the Eddington limits and thus growing mammoth. The third opinion says that the black hole consumes more than actually possible in a normal way. This happens when the black hole spins slower than then normal speed. The slower black holes consume more matters and grow in size.
WISE has been engaged in finding exceptional galaxies like this new discovery. The infrared images captured by it have revealed various spectacular objects and events around the universe. According to studies these rare cosmic events may not be visible if WISE had not shown them. Studies have revealed 20 such ELIGRs have been detected so far. Some of these galaxies have very poor luminosity due to obstruction of thickly coated dust particles around them preventing infrared light to come out properly.
Supernova is one of the most spectacular events in the universe. Supernovae occur when small dense stars known as white dwarfs explode with unimaginable intensity. These kinds of explosions occur once in a century and needless to say such incidents are very rarely visible.
On 3rd May 2014, a team of observers led by Shrinivas Kulkarni at iPTF (intermediate Palomar Transient Factory) discovered a type Ia supernova in a nearby galaxy IC831 about 300 million light years away. The astronomers were very skeptical about the reasons behind formation of Supernova from a white dwarf, but this new observation has given birth of two different theories regarding the formation of Supernovae.
There are two competing origin theories of Supernova. In both the theories one common point of view is that white dwarf explodes in one of the pair of two stars with common centre of mass. The first theory also known as double-degenerate model proposes that the companion of the exploded white dwarf is also a white dwarf and thus two similar white dwarfs initiate a supernova. The second theory, known as single-degenerate model opines that the second star may be a sun like star or a red giant. The huge gravitational attraction of the white dwarf pulls out materials from the second star and creates a nuclear explosion inside the white dwarf.
The information collected and images analyzed by the iPTF member Yi Cao and Caltech graduate students show that single-degenerate model is very suitable with the observed happenings in the supernova on 3rd May 2014. Cao and his team members used UV light analysis to further spot this type of Supernova-Companion collision in the universe. However, astronomers don’t rule out the occurrences of double-degenerate model of explosions.
Astronomers are now on search for more and more la Supernova to make sure that both theories are very much valid in different situations.