(Press-News.org) Contact information: Dave Finley
dfinley@nrao.edu
575-835-7302
National Radio Astronomy Observatory
New studies give strong boost to binary-star formation theory
VLA observations support 1 competing explanation for how double stars are formed
Using the new capabilities of the upgraded Karl G. Jansky Very Large Array (VLA), scientists have discovered previously-unseen binary companions to a pair of very young protostars. The discovery gives strong support for one of the competing explanations for how double-star systems form.
Astronomers know that about half of all Sun-like stars are members of double or multiple-star systems, but have debated over how such systems are formed.
"The only way to resolve the debate is to observe very young stellar systems and catch them in the act of formation," said John Tobin, of the National Radio Astronomy Observatory (NRAO). "That's what we've done with the stars we observed, and we got valuable new clues from them," he added.
Their new clues support the idea that double-star systems form when a disk of gas and dust whirling around one young star fragments, forming another new star in orbit with the first. Young stars that still are gathering matter from their surroundings form such disks, along with jet-like outflows rapidly propelling material in narrow beams perpendicular to the disk.
When Tobin and an international team of astronomers studied gas-enshrouded young stars roughly 1,000 light-years from Earth, they found that two had previously-unseen companions in the plane where their disks would be expected, perpendicular to the direction of the outflows from the systems. One of the systems also clearly had a disk surrounding both young stars.
"This fits the theoretical model of companions forming from fragmentation in the disk," Tobin said. "This configuration would not be required by alternative explanations," he added.
The new observations add to a growing body of evidence supporting the disk-fragmentation idea. In 2006, a different VLA observing team found an orbiting pair of young stars, each of which was surrounded by a disk of material. The two disks, they found, were aligned with each other in the same plane. Last year, Tobin and his colleagues found a large circumstellar disk forming around a protostar in the initial phases of star formation. This showed that disks are present early in the star formation process, a necessity for binary pairs to form through disk fragmentation.
"Our new findings, combined with the earlier data, make disk fragmentation the strongest explanation for how close multiple star systems are formed," said Leslie Looney of NRAO and the University of Illinois.
"The increased sensitivity of the VLA, produced by a decade-long upgrade project completed in 2012, made the new discovery possible," Claire Chandler of NRAO said.
The new capability was particularly valuable at the VLA's highest frequency band, from 40-50 GHz, where dust in the disks surrounding young stars emits radio waves. The astronomers observed the young stars during 2012 with the VLA and with the Combined Array for Research in Millimeter-wave Astronomy (CARMA) in California.
Tobin, Chandler, and Looney were part of a research team of astronomers from the U.S., Mexico, and the Netherlands. The scientists published their findings in the Astrophysical Journal.
###
The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.
New studies give strong boost to binary-star formation theory
VLA observations support 1 competing explanation for how double stars are formed
2013-12-31
ELSE PRESS RELEASES FROM THIS DATE:
Final recommendations on lung cancer screening
2013-12-31
Final recommendations on lung cancer screening
Embargoed news from Annals of Intenral Medicine
Final word: Task Force says screen high-risk populations for lung cancer
High-risk adults between the ages of 55 and 80 should receive annual lung cancer screening ...
Climate change spurs tropical mangroves to expand in the north
2013-12-31
Climate change spurs tropical mangroves to expand in the north
As mangrove trees lose ground to deforestation and urban sprawl, one development seems to be giving them a boost: climate change. Fewer winter cold snaps have enabled them to conquer new territory around their northern ...
Mangroves expand north as Florida freezes decline
2013-12-31
Mangroves expand north as Florida freezes decline
Mangrove forests have been expanding northward along the Atlantic coast of Florida for the last few decades not because of a general warming trend, but likely because cold snaps there are becoming a thing of the ...
With few hard frosts, tropical mangroves push north
2013-12-31
With few hard frosts, tropical mangroves push north
N Florida coast transformed by extreme weather change, not overall warming
COLLEGE PARK, MD – Cold-sensitive mangrove forests have expanded dramatically along Florida's Atlantic Coast as the frequency of killing frosts ...
Minority physicians care for a majority of underserved patients in the US
2013-12-31
Minority physicians care for a majority of underserved patients in the US
Minority physicians also play a large role in the care of patients with poorer health, according to a new study in JAMA Internal Medicine
CAMBRIDGE, Mass. – Black, Hispanic and Asian ...
Conversations on sex lacking between doctors and teens
2013-12-31
Conversations on sex lacking between doctors and teens
DURHAM, N.C. – Doctors are missing a prime opportunity to share information about sex with their teenage patients by failing to broach the subject during checkups, according to researchers ...
High good and low bad cholesterol levels are healthy for the brain, too
2013-12-31
High good and low bad cholesterol levels are healthy for the brain, too
(SACRAMENTO, Calif.) -- High levels of "good" cholesterol and low levels of "bad" cholesterol are correlated with lower levels of the amyloid plaque deposition ...
Field trial with lignin modified poplars shows potential for bio-based economy
2013-12-31
Field trial with lignin modified poplars shows potential for bio-based economy
But work still needs to be done
The results of a field trial with genetically modified poplar trees in Zwijnaarde, Belgium, shows that the wood of lignin ...
Most clinical studies on vitamins flawed by poor methodology
2013-12-31
Most clinical studies on vitamins flawed by poor methodology
CORVALLIS, Ore. – Most large, clinical trials of vitamin supplements, including some that have concluded they are of no value or even harmful, have a flawed methodology that renders them largely ...
Molecular evolution of genetic sex-determination switch in honeybees
2013-12-31
Molecular evolution of genetic sex-determination switch in honeybees
5 amino acid differences separate males from females
It's taken nearly 200 years, but scientists in Arizona and Europe have teased out how the molecular switch for sex gradually ...
LAST 30 PRESS RELEASES:
Intra-arterial tenecteplase for acute stroke after successful endovascular therapy
Study reveals beneficial microbes that can sustain yields in unfertilized fields
Robotic probe quickly measures key properties of new materials
Climate change cuts milk production, even when farmers cool their cows
Frozen, but not sealed: Arctic Ocean remained open to life during ice ages
Some like it cold: Cryorhodopsins
Demystifying gut bacteria with AI
Human wellbeing on a finite planet towards 2100: new study shows humanity at a crossroads
Unlocking the hidden biodiversity of Europe’s villages
Planned hydrogen refuelling stations may lead to millions of euros in yearly losses
Planned C-sections increase the risk of certain childhood cancers
Adults who have survived childhood cancer are at increased risk of severe COVID-19
Drones reveal extreme coral mortality after bleaching
New genetic finding uncovers hidden cause of arsenic resistance in acute promyelocytic leukemia
Native habitats hold the key to the much-loved smashed avocado’s future
Using lightning to make ammonia out of thin air
Machine learning potential-driven insights into pH-dependent CO₂ reduction
Physician associates provide safe care for diagnosed patients when directly supervised by a doctor
How game-play with robots can bring out their human side
Asthma: patient expectations influence the course of the disease
UNM physician tests drug that causes nerve tissue to emit light, enabling faster, safer surgery
New study identifies EMP1 as a key driver of pancreatic cancer progression and poor prognosis
XPR1 identified as a key regulator of ovarian cancer growth through autophagy and immune evasion
Flexible, eco-friendly electronic plastic for wearable tech, sensors
Can the Large Hadron Collider snap string theory?
Stuckeman professor’s new book explores ‘socially sustainable’ architecture
Synthetic DNA nanoparticles for gene therapy
New model to find treatments for an aggressive blood cancer
Special issue of Journal of Intensive Medicine analyzes non-invasive respiratory support
T cells take aim at Chikungunya virus
[Press-News.org] New studies give strong boost to binary-star formation theoryVLA observations support 1 competing explanation for how double stars are formed