Nav: Home

Scientists discover a small, dense planet orbiting a white dwarf

April 04, 2019

A new study reports discovery of one of the first small, intact planetary bodies orbiting a white dwarf star, a finding that sheds light into the twilight years of planetary systems. To date, scientists have identified about 3,000 stars that host one or more planets, most of which are main-sequence stars similar to the Sun. When such main sequence stars run out of fuel after billions of years, they transition into smaller white dwarfs, which researchers suspect could host surviving planets. Some white dwarfs show signatures of debris around them, probably from planets that were destroyed during the transition period, but evidence of intact planets around these stellar remnants has been lacking. In this study, Christopher Manser and colleagues used spectroscopy to study the gas in a debris disc surrounding the white dwarf SDSS J122859.93+104032.9. Their analysis revealed a periodic variation in gas emission lines that they concluded must be caused by a small planetary body (called a planetesimal) orbiting within the disc. The scientists calculated that the planetesimal, which orbits close to the white dwarf every two hours, must be unusually dense and no larger than 600 kilometers in diameter to avoid being ripped apart by the star's gravitational forces. Based on the object's high density, Manser et al. speculate that the planetesimal may be the remnant core of a planet whose outer layers were stripped away by the star's tidal forces. It is thus among the first detections of an intact planetesimal orbiting a white dwarf. In a related Perspective, Luca Fossati notes that the study's methods could help identify other planetesimals orbiting white dwarfs that cannot be detected with traditional planet-hunting techniques.

American Association for the Advancement of Science

Related Planets Articles:

Ultracool dwarf and the 7 planets
Astronomers have found a system of seven Earth-sized planets just 40 light-years away.
ALMA measures size of seeds of planets
Researchers using the Atacama Large Millimeter/submillimeter Array (ALMA), have for the first time, achieved a precise size measurement of small dust particles around a young star through radio-wave polarization.
Origin of minor planets' rings revealed
A team of researchers has clarified the origin of the rings recently discovered around two minor planets known as centaurs, and their results suggest the existence of rings around other centaurs.
Are planets setting the sun's pace?
The sun's activity is determined by the sun's magnetic field.
A better way to learn if alien planets have the right stuff
A new method for analyzing the chemical composition of stars may help scientists winnow the search for Earth 2.0.
A new Goldilocks for habitable planets
The search for habitable, alien worlds needs to make room for a second 'Goldilocks,' according to a Yale University researcher.
Probing giant planets' dark hydrogen
Hydrogen is the most-abundant element in the universe, but there is still so much we have to learn about it.
Universe's first life might have been born on carbon planets
Our Earth consists of silicate rocks and an iron core with a thin veneer of water and life.
Number of habitable planets could be limited by stifling atmospheres
New research has revealed that fewer than predicted planets may be capable of harbouring life because their atmospheres keep them too hot.
Footprints of baby planets in a gas disk
A new analysis of the ALMA data for a young star HL Tauri provides yet more firm evidence of baby planets around the star.

Related Planets Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Moving Forward
When the life you've built slips out of your grasp, you're often told it's best to move on. But is that true? Instead of forgetting the past, TED speakers describe how we can move forward with it. Guests include writers Nora McInerny and Suleika Jaouad, and human rights advocate Lindy Lou Isonhood.
Now Playing: Science for the People

#527 Honey I CRISPR'd the Kids
This week we're coming to you from Awesome Con in Washington, D.C. There, host Bethany Brookshire led a panel of three amazing guests to talk about the promise and perils of CRISPR, and what happens now that CRISPR babies have (maybe?) been born. Featuring science writer Tina Saey, molecular biologist Anne Simon, and bioethicist Alan Regenberg. A Nobel Prize winner argues banning CRISPR babies won’t work Geneticists push for a 5-year global ban on gene-edited babies A CRISPR spin-off causes unintended typos in DNA News of the first gene-edited babies ignited a firestorm The researcher who created CRISPR twins defends...