Rare doomed planet with extreme seasons discovered

Illustration provided by the University of Heidelberg of the orbit of

Kepler-432b (inner, red) in comparison to the orbit of Mercury around

the Sun (outer, orange). The red dot in the middle indicates the

position of the star around which the planet is orbiting. The size of

the star is shown to scale, while the size of the planet has been

magnified ten times for illustration purposes. (Graphic: Dr. Sabine Reffert)

Excerpt from foxnews.com/science

A rare planet has been discovered, and it doesn’t seem like a stop

anyone would want to make on an intergalactic cruise. Found by two

research teams independently of each other, Kepler-432b is extreme in

its mass, density, and weather. Roughly the same size of Jupiter, the

planet is also doomed- in 200 million years it will be consumed by its

sun. “Kepler-432b is definitively a rarity among exoplanets around giant

stars: it is a close-in gas-giant planet orbiting a star whose radius

is ‘quickly’ increasing,” Davide Gandolfi, from the Landessternwarte

Koenigstuhl (part of the Centre for Astronomy of the University of

Heidelberg), told FoxNews.com. “The orbit of the planet has a radius of

about 45 million kilometers [28 million miles] (as a reference point,

the Earth-Sun distance is about 150 million kilometers [93.2 Million

miles]), while most of the planets known to orbit giant stars have wider

orbits. The stellar radius is already 3 million kilometers [almost 2

million miles] (i.e., about 4 times the Sun radius) and in less than 200

million years it will be large enough for the star to swallow up its

planet.”

Gandolfi, a member of one of the research groups who discovered the

rare planet, explains that much like Jupiter, Kepler-432b is a gas-giant

celestial body composed mostly of hydrogen and helium, and is most

likely to have a dense core that accounts for 6 percent or less of the

planet’s mass. “The planet has a mass six times that of Jupiter, but is

about the same size!” he says. “This means that it is not one of the

largest planets yet discovered: it is one of the most massive!” The

planet’s orbit brings it extremely close to its host star on some

occasions, and very far away at others, which creates extreme seasonal

changes. In its year – which lasts 52 Earth days – winters can get a

little chilly and summers a bit balmy, to say the least. According to

Gandolfi, “The highly eccentric orbit brings Kepler-432b at ‘only’ 24

million kilometers [15 million miles] from its host star, before taking

it to about three times as far away. This creates large temperature

excursions over the course of the planet year, which is of only 52 Earth

days. During the winter season, the temperature on Kepler-432b drops

down to 500 degrees Celsius [932 degrees Fahrenheit], whereas in summer

it can goes up to nearly 1000 degrees Celsius [1832 degrees

Fahrenheit].”

Then again, if you are crazy enough to visit Kepler-432b, you’d

better do it fast. As stated before, its host star is set to swallow the

planet whole in 200 million years, making the celestial body a rare

find. “The paucity of close-in planets around giant stars is likely to

be due to the fact that these planets have been already swallowed up by

their host stars,” Gandolfi says. “Kepler-432b has been discovered ‘just

in time before dinner!” The host star, which is red and possesses 1.35

times the mass of our sun, has partly exhausted the nuclear fuel in its

core, and is slowly expanding, eventually growing large enough to

swallow Kepler-432b. According to Gandolfi, this is a natural

progression for all stars. “Stars first generate nuclear energy in their

core via the fusion of Hydrogen into Helium,” he explained. “At this

stage, their radii basically do not change much. This is because the

outward thermal pressure produced by the nuclear fusion in the core is

balanced by the inward pressure of gravitational collapse from the

overlying layers. In other words, the nuclear power is the star pillar!

Our Sun is currently ‘burning’ hydrogen in its core (please note that I

used quotes: ‘burning’ does not mean a chemical reaction- we are talking

about nuclear fusion reaction). However, this equilibrium between the

two pressures does not last forever. Helium is heavier than hydrogen and

tends to sink. The stellar core of the Kepler-432b’s host star is

currently depleted of hydrogen and it is mainly made of inert helium.

The star generates thermal energy in a shell around the core through the

nuclear fusion of hydrogen into helium. As a result of this, the star

expands and cools down. This is why we call it ‘red giant’- the reddish

color comes from the fact that the external layers of the atmosphere of

the star are cooling down because they expand.”

Both research teams (the other was from the Max Planck Institute for

Astronomy in Heidelberg) used Calar Alto Observatory’s 7.2- foot

telescope in Andalucia, Spain. The planet was also studied by

Landessternwarte Koenigstuhl researchers using the 8.5-foot Nordic

Optical Telescope on La Palma, which is located in Spain’s Canary

Islands.

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Rare doomed planet with extreme seasons discovered