Planetary system Current Affairs - 2019
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Scientists from Physical Research Laboratory (PRL), Ahmedabad have discovered for first time distant planet revolving around Sun-like star. Both the planet and the star have been named EPIC. With this discovery India joins handful of countries which have discovered planets around stars.
The planet has been named as EPIC 211945201b (or K2-236b) and host star has been named EPIC 211945201 (or K2-236). The EPIC planet is six times bigger than Earth and revolves around host about 600 light years away. EPIC was found circling very close to its host star, going around it once in about 19.5 days.
EPIC planet is smaller in size compared to Saturn and but is bigger than Neptune. Its mass is about 27 times Earth’s and six times that of Earth at radius. Its 60% mass may be made up of heavy elements like ice, silicates and iron. The planet is unlikely to be inhabitable because of its high surface temperature of around 600°C.
The discovery was made using PRL-designed PARAS (PRL Advance Radial-velocity Abu-sky Search) spectrograph to measure and confirm the mass of the new planet. PARAS is first of its kind spectrograph in the country which can measure the mass of planet going around star. It is integrated with 1.2-metre telescope located at PRL’s Gurushikhar Observatory in Mount Abu, Rajasthan. Very few such spectrographs exist around the world (mostly in US and in Europe) that can do such precise measurements.
The discovery of EPIC planetary system adds to sparse catalogue of 22 other confirmed exoplanet systems that have mass and radius in range between Saturn and Neptune. It will help in understanding formation mechanism of such super-Neptune or sub-Saturn kind of planets that are too close to host star. This planet is very unlike those in our own Solar System, by studying them will tell us more about how planetary systems are formed.
Physical Research Laboratory (PRL)
It is national research institute for space and allied sciences, supported mainly by Department of Space (DST) of Government of India. It conducts research programmes in astronomy and astrophysics, atmospheric sciences and aeronomy, solar system, Earth sciences and theoretical physic. It was founded in November 1947 by Dr. Vikram Sarabhai. It is located in Ahmedabad, Gujarat.
NASA’s will launch humanity’s first mission Parker Solar Probe (PSP) to the Sun in July 31, 2018. It is undergoing final preparations for its scheduled launch on board of NASA’s Delta IV Heavy launch vehicle from Kennedy Space Centre in Florida. After its launch, the probe will orbit directly through solar atmosphere — the corona — closer to surface than any human-made object has ever gone.
Parker Solar Probe mission
It is NASA’s first planned robotic spacecraft to study outer corona of Sun. It has been designed and built by Johns Hopkins University Applied Physics Laboratory. It is named after solar astrophysicist Eugene Parker, first spacecraft of NASA to be named after living person.
The spacecraft is designed to endure harsh environment near Sun, by approaching within 8.5 solar radii (5.9 million kilometers) to ‘surface’ (photosphere) of Sun where incident solar intensity is approximately 520 times intensity at Earth orbit.
The probe will be fitted with thermal protection system (TPS) or heat shield made of reinforced carbon-carbon composite that will allow it to survive temperatures in Sun’s corona. It main systems and scientific instruments are located in central portion of shield’s shadow, where direct radiation from Sun is fully blocked.
The primary power for mission is dual system of solar panels (photovoltaic array). Secondary source consists of much smaller secondary array power that uses pumped-fluid cooling to maintain operating temperature.
Scientific goals of PSP
- Determine structure and dynamics of magnetic fields at sources of solar wind.
- Trace flow of energy that heats corona and accelerates solar wind.
- Determine what mechanisms accelerate and transport energetic particles.
- Explore dusty plasma near Sun and its influence on solar wind and energetic particle formation.
In its seven-year mission, PSP will explore Sun’s outer atmosphere and make critical observations to answer questions about physics of stars. Its data will also be useful in improving forecasts of major eruptions on Sun and subsequent space weather events that impact technology on Earth, as well as satellites and astronauts in space.