Featured Research

from universities, journals, and other organizations

Looking for life by the light of dying stars

Date:
April 24, 2013
Source:
American Friends of Tel Aviv University
Summary:
Astronomers have now demonstrated that with the advanced technology available in the next decade we should be able to detect biomarkers like oxygen and methane in the planets that orbit dead stars called "white dwarfs" -- and to find new forms of life on those planets.

NGC 2440: Cocoon of a new white dwarf.
Credit: H. Bond (STScI), R. Ciardullo (PSU), WFPC2, HST, NASA

Because it has no source of energy, a dead star -- known as a white dwarf -- will eventually cool down and fade away. But circumstantial evidence suggests that white dwarfs can still support habitable planets, says Prof. Dan Maoz of Tel Aviv University's School of Physics and Astronomy.

Related Articles


Now Prof. Maoz and Prof. Avi Loeb, Director of Harvard University's Institute for Theory and Computation and a Sackler Professor by Special Appointment at TAU, have shown that, using advanced technology to become available within the next decade, it should be possible to detect biomarkers surrounding these planets -- including oxygen and methane -- that indicate the presence of life.

Published in the Monthly Notices of the Royal Astronomical Society, the researchers' "simulated spectrum" demonstrates that the James Webb Space Telescope (JWST), set to be launched by NASA in 2018, will be capable of detecting oxygen and water in the atmosphere of an Earth-like planet orbiting a white dwarf after only a few hours of observation time -- much more easily than for an Earth-like planet orbiting a sun-like star.

Their collaboration is made possible by the Harvard TAU Astronomy Initiative, recently endowed by Dr. Raymond and Beverly Sackler.

Faint light, clear signals

"In the quest for extraterrestrial biological signatures, the first stars we study should be white dwarfs," said Prof. Loeb. Prof. Maoz agrees, noting that if "all the conditions are right, we'll be able to detect signs of life" on planets orbiting white dwarf stars using the much-anticipated JWST.

An abundance of heavy elements already observed on the surface of white dwarfs suggest rocky planets orbit a significant fraction of them. The researchers estimate that a survey of 500 of the closest white dwarfs could spot one or more habitable planets.

The unique characteristics of white dwarfs could make these planets easier to spot than planets orbiting normal stars, the researchers have shown. Their atmospheres can be detected and analyzed when a star dims as an orbiting planet crosses in front of it. As the background starlight shines through the planet's atmosphere, elements in the atmosphere will absorb some of the starlight, leaving chemical clues of their presence -- clues that can then be detected from the JWST.

When an Earth-like planet orbits a normal star, "the difficulty lies in the extreme faintness of the signal, which is hidden in the glare of the 'parent' star," Prof. Maoz says. "The novelty of our idea is that, if the parent star is a white dwarf, whose size is comparable to that of an Earth-sized planet, that glare is greatly reduced, and we can now realistically contemplate seeing the oxygen biomarker."

In order to estimate the kind of data that the JWST will be able to see, the researchers created a "synthetic spectrum," which replicates that of an inhabited planet similar to Earth orbiting a white dwarf. They demonstrated that the telescope should be able to pick up signs of oxygen and water, if they exist on the planet.

A critical sign of life

The presence of oxygen biomarkers would be the most critical signal of the presence of life on extraterrestrial planets. Earth's atmosphere, for example, is 21 percent oxygen, and this is entirely produced by our planet's plant life as a result of photosynthesis. Without the existence of plants, an atmosphere would be entirely devoid of oxygen.

The JWST will be ideal for hunting out signs of life on extraterrestrial planets because it is designed to look into the infrared region of the light spectrum, where such biomarkers are prominent. In addition, as a space-based telescope, it will be able to analyze the atmospheres of Earth-like planets outside our solar system without weeding out the similar signatures of Earth's own atmosphere.


Story Source:

The above story is based on materials provided by American Friends of Tel Aviv University. Note: Materials may be edited for content and length.


Cite This Page:

American Friends of Tel Aviv University. "Looking for life by the light of dying stars." ScienceDaily. ScienceDaily, 24 April 2013. <www.sciencedaily.com/releases/2013/04/130424112318.htm>.
American Friends of Tel Aviv University. (2013, April 24). Looking for life by the light of dying stars. ScienceDaily. Retrieved December 20, 2014 from www.sciencedaily.com/releases/2013/04/130424112318.htm
American Friends of Tel Aviv University. "Looking for life by the light of dying stars." ScienceDaily. www.sciencedaily.com/releases/2013/04/130424112318.htm (accessed December 20, 2014).

Share This


More From ScienceDaily



More Space & Time News

Saturday, December 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Spokesman: 'NORAD Ready to Track Santa'

Spokesman: 'NORAD Ready to Track Santa'

AP (Dec. 19, 2014) Pentagon spokesman Rear Adm. John Kirby said that NORAD is ready to track Santa Claus as he delivers gifts next week. Speaking tongue-in-cheek, he said if Santa drops anything off his sleigh, "we've got destroyers out there to pick them up." (Dec. 19) Video provided by AP
Powered by NewsLook.com
NASA's Planet-Finding Kepler Mission Isn't Over After All

NASA's Planet-Finding Kepler Mission Isn't Over After All

Newsy (Dec. 18, 2014) More than a year after NASA declared the Kepler spacecraft broken beyond repair, scientists have figured out how to continue getting useful data. Video provided by Newsy
Powered by NewsLook.com
Rover Finds More Clues About Possible Life On Mars

Rover Finds More Clues About Possible Life On Mars

Newsy (Dec. 17, 2014) NASA's Curiosity rover detected methane on Mars and organic compounds on the surface, but it doesn't quite prove there was life ... yet. Video provided by Newsy
Powered by NewsLook.com
Evidence of Life on Mars? NASA Rover Finds Methane, Organic Chemicals

Evidence of Life on Mars? NASA Rover Finds Methane, Organic Chemicals

Reuters - US Online Video (Dec. 16, 2014) NASA's Mars Curiosity rover finds methane in the Martian atmosphere and organic chemicals in the planet's soil, the latest hint that Mars was once suitable for microbial life. Linda So reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins