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NASA probe flies past Pluto, world awaits historic images

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Applause by Nasa New Horizons team as countdown to the Pluto flyby ends. Picture sent on twitter by Nasa
Picture sent on twitter by NASA

Washington, In what may necessitate rewriting of science books, NASA’s New Horizons probe — after travelling over 4.8 billion km — on Tuesday flew past the mysterious dwarf planet Pluto on the outermost fringes of the solar system.

Flying past Pluto at a distance of about 12,500 km at around 5 p.m. (Indian standard Time), the probe, launched a decade ago, was expected to beam back key images of Pluto’s surface to Earth in about nine hours — the time it takes the communication to reach Earth from Pluto.

The images will also help scientists explore the mysterious Kuiper Belt — a huge band of planetary debris left over from the solar system’s formation 4.5 billion years ago.

The most dangerous hazards for the probe — flying at a speed of 45,000 km per hour — were dust particles trapped in orbit around Pluto and a strike can cripple the spacecraft, scientists said, but added that such a risk was very low.

The first images will debut on Facebook-owned photo-sharing website Instagram, NASA has announced.

“We made an editorial decision to give the world a sneak peek of the image on Instagram,” NASA social media manager John Yembrick told wired.com.

On board the New Horizons are seven sophisticated science instruments and the ashes of Clyde Tombaugh, the astronomer who discovered Pluto in 1930.

NASA was expecting a dark grey icy planet but the probe found it is red and appeared to be oxidized like Mars.

Earlier, the New Horizons probe settled one of the most basic questions about Pluto — its size. Mission scientists have found Pluto to be 2,370 km in diameter, somewhat larger than many prior estimates.

Images acquired with the Long Range Reconnaissance Imager (LORRI) on board the New Horizon probe were used to make this determination.

The result confirms that Pluto is larger than all other known solar system objects beyond the orbit of Neptune, the US space agency said in a statement.

“The size of Pluto has been debated since its discovery in 1930. We are excited to finally lay this question to rest,” said mission scientist Bill McKinnon from Washington University in St Louis.

Pluto’s newly-estimated size means that its density is slightly lower than previously thought, and the fraction of ice in its interior is slightly higher.

Measuring Pluto’s size has been a decades-long challenge due to complicating factors from its atmosphere.

Its largest moon Charon lacks a substantial atmosphere, and its diameter was easier to determine using ground-based telescopes.

New Horizons observations of Charon confirm its previous estimated size of 1,208 km across.

Two other moons – Nix and Hydra – were discovered using the Hubble Space Telescope in 2005. Nix is estimated to be about 35 km across while Hydra is roughly 45 km across.

These sizes lead mission scientists to conclude that their surfaces are quite bright, possibly due to the presence of ice.

Pluto’s two smallest moons, Kerberos and Styx, are smaller and fainter than Nix and Hydra and are harder to measure, the US space agency said.

(IANS)

 

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Habitability Of Surrounding Planets Affected By Super Flares Of Red Dwarfs: NASA

Red dwarfs -- especially young red dwarfs -- are active stars, producing flares blast out energy

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NASA, space, red dwarf
Superflares from red dwarfs may affect habitability of planets Pixabay

Using NASA’s Hubble Space Telescope, astronomers have found that violent outbursts, or superflares, from red dwarf stars could affect the habitability of any planets orbiting it.

Young low-mass stars flare much more frequently and more energetically than old stars and middle-age stars like our Sun, the findings of the study published in the Astrophysical Journal showed.

The findings are based on observations of the flare frequency of 12 red dwarfs.

Hubble is observing such stars through a large programme called HAZMAT — Habitable Zones and M dwarf Activity across Time.

“M dwarf” is the astronomical term for a red dwarf star — the smallest, most abundant and longest-living type of star in our galaxy.

Hubble Telescope. red dwarf
Hubble Telescope. Flickr

The HAZMAT programme is an ultraviolet survey of red dwarfs at three different ages — young, intermediate, and old.

“The goal of the HAZMAT programme is to help understand the habitability of planets around low-mass stars,” explained the programme’s principal investigator, Evgenya Shkolnik from Arizona State University.

“These low-mass stars are critically important in understanding planetary atmospheres,” Shkolnik added.

Stellar flares from red dwarfs are particularly bright in ultraviolet wavelengths, compared with Sun-like stars.

Red dwarf  planet
Artist’s view of planets transiting red dwarf star in TRAPPIST-1 system. Flickr

Hubble’s ultraviolet sensitivity makes the telescope very valuable for observing these flares.

The flares are believed to be powered by intense magnetic fields that get tangled by the roiling motions of the stellar atmosphere.

When the tangling gets too intense, the fields break and reconnect, unleashing tremendous amounts of energy.

The team found that the flares from the youngest red dwarfs they surveyed — just about 40 million years old — are 100 to 1,000 times more energetic than when the stars are older.

This younger age is when terrestrial planets are forming around their stars.

Red dwarf
This illustration shows a red dwarf star orbited by a hypothetical exoplanet. NASA

About three-quarters of the stars in our Milky Way galaxy are red dwarfs. Most of the galaxy’s “habitable-zone” planets — planets orbiting their stars at a distance where temperatures are moderate enough for liquid water to exist on their surface — orbit red dwarfs.

In fact, the nearest star to our Sun, a red dwarf named Proxima Centauri, has an Earth-size planet in its habitable zone.

Also Read: NASA Plans For Science Payloads For Delivery To Moon

However, red dwarfs — especially young red dwarfs — are active stars, producing flares that could blast out so much energy that it disrupts and possibly strips off the atmospheres of these fledgling planets. (IANS)