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Fact Box: Hottest Known Planet in Universe

Scientists have discovered the hottest known exoplanet, designated KELT-9b which is warmer than most stars in the universe. The study has been published in the journal Nature.

Exoplanet is a planet that does not orbit the Sun and instead orbits a different star, stellar remnant, or brown dwarf. They are also called as extrasolar planet.

Salient Highlights

  • The planet orbits a massive star KELT-9 every day and a half.
  • The planet’s day-side temperature is 4,326 degree Celsius and is only 926 degree Celsius cooler than the Sun.
  • The planet is located 650 light years from Earth and sports a giant, glowing gas tail like a comet.
  • The ultraviolet radiation experienced by the planet from its star KELT-9 is so fierce that the planet may be evaporating producing a glowing gas tail.
  • The Jupiter-like planet is 2.8 times more massive than Jupiter. However, it is only half as dense as that of the Jupiter.
  • Due to extreme radiation from its host star the atmosphere of the planet has puffed up like a balloon. It has been classified as a planet by considering its mass but its atmosphere is not similar to any other known planet.
  • Due to the bombardment of stellar radiation, the planet is very hot so much so that the  molecules such as water, carbon dioxide and methane can not form there.

Background

The first planet outside our solar system was found out in 1995. With the help of NASA’s Kepler telescope, the discovery of planets has become easier. So far, astronomers have identified 52 potentially habitable planets and around 3,600 planets outside our solar system. With the launch of James Webb Space Telescope (JWST) by NASA in 2018, chances of studying planets and detecting a familiar atmosphere will increase manifold. JWST will succeed the Hubble space telescope.

 

 

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Astronomers discover Venus-like planet orbiting a dim star Kepler-1649

Astronomers using NASA’s Kepler space telescope have discovered a Venus-like planet orbiting a dim star called Kepler-1649.

The newly found planet is one-fifth the diameter of our Sun and is only slightly larger than Earth. It is located 219 light years away from Earth.

Key Facts
  • The Venus-like planet tightly embraces its low-temperature star Kepler-1649 by encircling it every nine days.
  • The tight orbit around the star causes the flux of sunlight reaching it to be 2.3 times as great as the solar flux on Earth. For comparison, the solar flux on Venus is 1.9 times the terrestrial value (on earth).
  • The discovery will provide insight into the nature of planets encircling around M dwarf stars, by far the most common type in the universe.

About Venus

  • Venus is the second planet from the Sun, orbiting it every 224.7 Earth days. It is named after the Roman goddess of love and beauty.
  • It is a terrestrial planet and is sometimes called Earth’s “sister planet” because of their similar size, mass, proximity to Sun, and bulk composition. It has no natural satellite.
  • But it is radically different from Earth in other respects. It has densest atmosphere of four terrestrial planets, consisting of more than 96% CO2. The atmospheric pressure at its planet’s surface is 92 times that of Earth.
  • Note: Venus is by far the hottest planet in the Solar System, with a mean surface temperature 462 °C even though Mercury is closer to the Sun.

About Kepler Space Telescope (KST)

  • KST is an unmanned space observatory launched in 2009 by National Aeronautics and Space Administration (NASA).
  • It is tasked with determining how commonly, Earth-like planets occur throughout the Milky Way galaxy.
  • KST works by observing a dimming in the light of a star, known as a transit, each time an orbiting planet passes in front of it.
  • It has been designed for a statistical mission and not to probe into the environmental conditions of planets that exist in the so-called Goldilocks zone (Habitable zone) of their stars.

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Scientists for first time saw eclipses of binary star shed light on orbiting exoplanet

A team of scientists from Raman Research Institute, Bengaluru and University of Delhi for the first time have seen indications of a massive planet orbiting a low mass X-ray binary star system.

The system MXB 1658-298 is an X-ray binary and a part of the constellation Ophiuchus (serpent bearer). It is nearly 30,000 light years away and the planet is expected to be nearly 8,000 times as massive as the earth. 

Key Facts
  • X-ray binaries consist of a pair of stars orbiting each other of which one is compact one such as a black hole or a neutron star.
  • In this case it is a neutron star which draws matter from its less-massive companion and generates X-rays which are detected by detectors placed in satellites in space.
  • This discovery is made with a new technique, X-Ray observation by measuring periodic delays in X-ray eclipses. It is a new technique of detecting exoplanets and observations are done from space observatories.
  • In X-ray binaries, the time in-between eclipses of the source can increase, decrease and also shows abrupt changes. But in MXB 1658-298, time between the eclipses increases and decreases periodically.

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