Irandaily | No. 4405 | Science

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Nearest Sun-Like Star Has Planets

The nearest single Sun-like star to the Earth hosts five planets--one of which is in the “habitable zone” where liquid water can exist, astronomers say.
Tau Ceti’s planetary quintet--reported in an online paper that will appear in Astronomy and Astrophysics--was found in existing planet-hunting data, BBC said.
The study’s refined methods of sifting through data should help find even more far-flung worlds.
The star now joins Alpha Centauri as a nearby star known to host planets.
In both those cases, the planets were found not by spying them through a telescope but rather by measuring the subtle effects they have on their host stars’ light.
In the gravitational dance of a planet around a star, the planet does most of the moving. But the star too is tugged slightly to and fro as the planet orbits, and these subtle movements of the star show up as subtle shifts in the color of the star’s light we see from Earth.
This “radial velocity” measurement is a tricky one; stars’ light changes also for a range of other reasons, and requires picking out the specifically planetary component from all this ‘noise’.
Now, Hugh Jones of the University of Hertfordshire and colleagues have refined their “noise modeling” in order to subtract it, and thereby see the smallest signals hiding in the data--starting with Tau Ceti.
“It’s a star on which we have a lot of data--an order of magnitude more data than we have for pretty much any other star,” Prof Jones told BBC News.
“It’s a good test case for how low can we go, what size of signals can we pick up.”
The team started with data from three planet-hunting missions: Harps, AAPS, and HiRes, all of which had data on Tau Ceti.
The trick to honing the technique was to put in “fake planets”--to add signals into the messy data that planets should add--and find ways to reduce the noise until the fake planets became more and more visible in the data.
“Putting all that together, we optimized a noise-modeling strategy that allows us to recover our fake signals--but in the process of doing that, we actually saw that we were finding signals as well,” Prof Jones said--actual planets.
The quintet includes planets between two and six times the Earth’s mass, with periods ranging from 14 to 640 days.
One of them, dubbed HD 10700e, lies about half as far from Tau Ceti as the Earth is from the Sun--and because Tau Ceti is slightly smaller and dimmer than our Sun, that puts the planet in the so-called habitable zone.

Rudolph’s Red Nose Mystery Solved

Most people know Rudolph the Red-Nosed Reindeer had a very shiny nose--but why? Medical researchers say they’ve now found the answer.
According to LiveScience, the secret to Rudolph’s rosy schnozzle is the dense network of blood vessels in his nose.
Reindeers have 25 percent more capillaries carrying red, oxygen-rich blood in their nasal architecture than humans, say the scientists from the Erasmus Medical Center in Rotterdam, the Netherlands, and the University of Rochester in New York.
“In colder climates and also when they are higher up in the atmosphere pulling Santa’s sleigh, the increase in blood flow in the nose will help keep the (nose’s) surface warm,” Dr. John Cullen of the University of Rochester told MedPage.
The dense network of blood vessels in reindeer noses is also essential for regulating the animal’s internal body temperature; like many mammals, reindeer don’t sweat.
The researchers took advantage of high-tech instruments like hand-held intravital video microscopes to compare the blood vessels of two reindeer (Rangifer tarandus) with those of human volunteers (five healthy humans and one with nasal polyps).
One of the human volunteers was examined after inhaling 0.0035 ounces (100 milligrams) of cocaine, “a drug routinely used in ear, nose, and throat medicine as a local anesthetic and vasoconstrictor”, the researchers write in the British Medical Journal this week.
“We’re kind of glad they didn’t do the same thing with the reindeer, because the last thing we would want is reindeer on cocaine, pulling Santa around the sky,” said Cullen.
Their results showed reindeer noses do turn a rosy red; after a treadmill test, the reindeer’s nose showed up as red (warm) in a thermographic image. In addition, they found glandlike structures in the nasal mucous membrane of reindeer and humans; the structures were surrounded by capillaries, and the researchers suspect, at least in humans, they secrete mucus.