Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Hunt for planets outside solar system uncovers a small one

26.01.2006


Perhaps edging closer to finding planets that harbor life, astronomers have discovered the smallest planet yet identified outside our solar system.



Researchers, including a University of Florida astronomer, found the planet, which has a mass about five times that of Earth, orbiting a small star near the center of the galaxy in the constellation Sagittarius.

Located about three times as far away from its star as the distance from Earth to the sun, it is probably too cold to support life. But its presence suggests there are many other small planets orbiting the star. That makes it likely that at least some are located in the so-called habitable zone, the region around stars where temperatures are moderate enough for liquid water to appear on their surfaces.


"The good thing about this is it shows that planets this size might be quite common in habitable zones," said Stephen Kane, a postdoctoral associate in UF’s astronomy department.

Kane co-authored a paper about the discovery set to appear Jan. 26 in the journal Nature.

Since the first planet was discovered outside our solar system in 1992, astronomers have found the vast majority of the 160-plus planets so far with a technique called radial velocity. The technique detects planets that are too faint to be seen with visual telescopes by observing the wobble in the stars induced by the orbiting planet.

Bigger planets have more gravitational pull, inducing bigger, more detectable wobbles. Also, the closer planets lie to the star, the more wobble they cause. As a result, radial velocity tends to turn up the largest, closest, hottest and consequently the most gaseous planets – planets, in other words, that are not good candidates for supporting life.

Astronomers discovered the new, small planet by tapping a completely different stellar phenomenon: galactic microlensing. Most easily observed with small, older stars known as M dwarfs, microlensing occurs when light from a distant star encounters the gravitational field of a closer star as the closer star passes in front or just to the side it. The gravitational field literally bends and magnifies the light.

The effect is a bit like the beam from a searchlight encountering a giant magnifying glass. But, for planet-finders, the key item of interest is that if the parent star is orbited by a planet, the planet’s gravitational field also acts as its own little lens -- magnifying some of the distant star’s light in a brief but distinctive flicker.

"There’s a very subtle effect, a spike, and that’s what we’re looking for," Kane said.

It’s rare for one star to pass so near another star that it causes microlensing to occur. The timing is also brief, with most microlensing events lasting 30 days or less. As a result, astronomers hunting such events focus their searches on the center of the galaxy, where stars are most densely distributed. This area is best viewed from the Southern Hemisphere, so astronomers coordinate observations using multiple telescopes in such places as Australia, Chile, South Africa and the Canary Islands.

"We have a real-time alert system," Kane said. "We’ve got people in Australia observing, and if they see something strange happen but their source is starting to set, they call up South Africa and say, ’Something’s happening here. Point your telescopes at this.’"

In the latest finding, some 73 astronomers affiliated with three independent groups coordinated observations of a microlensing event first identified on July 11, 2005. Nearly a month later, on Aug. 9, the astronomers observed "a short duration deviation from a single-lens light curve … due to a low-mass planet orbiting the lens star," the Nature paper says.

The planet is at the outer edge of the zone where it can be seen. With a surface temperature below 350 degrees below zero, it is probably rocky and icy. Even if conditions appeared more favorable for life, its location would make it tough to learn more: The planet is located 7,000 parsecs, or nearly 23,000 light years, from Earth.

That said, M dwarfs are the most common type of stars in the galaxy. The fact that microlensing uncovered such a small planet around one M dwarf suggests that there are likely many others, possibly with better conditions, Kane said.

"This has huge implications for finding life," he said.

Stephen Kane | EurekAlert!
Further information:
http://www.astro.ufl.edu

More articles from Physics and Astronomy:

nachricht Temperature-controlled fiber-optic light source with liquid core
20.06.2018 | Leibniz-Institut für Photonische Technologien e. V.

nachricht New material for splitting water
19.06.2018 | American Institute of Physics

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Temperature-controlled fiber-optic light source with liquid core

In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.

Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...

Im Focus: Overdosing on Calcium

Nano crystals impact stem cell fate during bone formation

Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...

Im Focus: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Munich conference on asteroid detection, tracking and defense

13.06.2018 | Event News

2nd International Baltic Earth Conference in Denmark: “The Baltic Sea region in Transition”

08.06.2018 | Event News

ISEKI_Food 2018: Conference with Holistic View of Food Production

05.06.2018 | Event News

 
Latest News

Better model of water under extreme conditions could aid understanding of Earth's mantle

21.06.2018 | Earth Sciences

What are the effects of coral reef marine protected areas?

21.06.2018 | Life Sciences

The Janus head of the South Asian monsoon

21.06.2018 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>