Four Exoplanets Detected around Nearby Star Tau Ceti

Share

Scientists have found tantalizing signs that there are four Earth-like planets orbiting Tau Ceti, a Sun-like star just 12 million light-years away. This means that liquid water could exist on the surface of the planets, making them prime candidates for exoplanets that could harbour life as it is known on Earth. The planets have masses as low as 1.7 Earth mass meaning they're some of the smallest planets ever discovered around a Sun-like star.

This is particularly interesting because it helps refine a technique to find other Earth-like planets based on how stars "wobble", tracking the minute gravitational effects of planets on the stars that orbit them.

"A real breakthrough [in this study] is that we were for the first time able to detect periodic movement of a sun-like star of only 30 centimeters per second", Toumi said.

"We are getting tantalizingly close to the 10 cm per second limit required for detecting Earth analogs", said team member Dr. Fabo Feng, also from the University of Hertfordshire. "Our detection of such weak wobbles is a milestone in the search for Earth analogs".

"Tau Ceti is the nearest Sun-like star to the Sun and finding habitable planets around it is exciting", Avi Loeb of Harvard's Center for Astrophysics told Gizmodo, although he too noted that their habitability is, right now, a question mark.

Rivaldo endorses 'good option' Coutinho as Barcelona begin life without Neymar
Have you read Trendiee Today? I'm not the best in pre-season - I'm not very patient. Liverpool have already rejected a £90m bid from Barca.

Gold Price Hits Highest Levels In Two Months
The producer price index for final demand edged down by 0.1% in July after inching up by 0.1% in June. Genesee & Wyoming (GWR) is posting a notable gain after reporting an increase in July traffic.

ISIS used eBay to funnel cash to operative in US
The man who allegedly received the money was American citizen Mohamed Elshinawy, arrested a year ago in Maryland. Elshinawy claims he did not plan to plan to carry out an attack, and he's now awaiting trial.

Tau Ceti is similar to our Sun in size and brightness, and like our Sun hosts a multi-planet system. A massive debris disc around the star would reduce the planets' habitability due to bombardment from asteroids and comets. But even if none of tau Ceti's planets are remotely habitable, the existence of such nearby cosmic neighbors would be a boon to search for life beyond Earth.

As a planet orbits, it causes its parent star to wobble by a tiny degree.

Mikko Tuomi, another researcher at the University of Herefordshire, explained, "We came up with an ingenious way of telling the difference between signals caused by planets and those caused by star's activity". However, the researchers say that their data seemed to show four rocky planets instead of just two, so they devised a way to make their technique more sensitive to weak planetary signals.

The team made the discovery by combining more than 6,000 observations from the UCLES spectrograph on the Anglo-Australian Telescope, the HIRES spectrograph on the Keck Telescope, and reanalyzing spectra taken with the HARPS spectrograph available through the European Southern Observatory public archive. That could be crucial, because while its easier to spot exoplanets around dim red dwarf stars like Trappist-1 using the transit method, astronomers are beginning to wonder if such stars can actually support life.

Share