PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Starless cloud cores reveal why some stars are bigger than others

2013-12-21
(Press-News.org) Contact information: Charles Blue
cblue@nrao.edu
434-296-0314
National Radio Astronomy Observatory
Starless cloud cores reveal why some stars are bigger than others

Massive stars – those at least 8 times the mass of our Sun – present an intriguing mystery: how do they grow so large when the vast majority of stars in the Milky Way are considerably smaller?

To find the answer, astronomers used the Atacama Large Millimeter/submillimeter Array (ALMA) telescope to survey the cores of some of the darkest, coldest, and densest clouds in our Galaxy to search for the telltale signs of star formation.

These objects, known as Infrared Dark Clouds, were observed approximately 10,000 light-years away in the direction of the constellations of Aquila and Scutum.

Since these cloud cores are so massive and dense, gravity should have already overwhelmed their supporting gas pressure, allowing them to collapse to form new, Sun-mass stars. If a star had not yet begun to shine, that would be a hint that something extra was supporting the cloud.

"A starless core would indicate that some force was balancing out the pull of gravity, regulating star formation, and allowing vast amounts of material to accumulate in a scaled-up version of the way our own Sun formed," remarked Jonathan Tan, an astrophysicist at the University of Florida, Gainesville, and lead author of a paper published today in the Astrophysical Journal. "This suggests that massive stars and Sun-like stars follow a universal mechanism for star formation. The only difference is the size of their parent clouds."

Average stars like our Sun begin life as dense, but relatively low-mass concentrations of hydrogen, helium, and other trace elements inside large molecular clouds. After the initial kernel emerges from the surrounding gas, material collapses under gravity into the central region in a relatively ordered fashion via a swirling accretion disk, where eventually planets can form. After enough mass accumulates, nuclear fusion begins at the core and a star is born.

While this model of star formation can account for the vast majority of stars in our Milky Way, something extra is needed to explain the formation of more massive stars. "Some additional force is needed to balance out the normal process of collapse, otherwise our Galaxy would have a fairly uniform stellar population," said Tan. "Alternatively, there has been speculation that two separate models of star formation are needed: one for Sun-like stars and one for these massive stars."

The key to teasing out the answer is to find examples of massive starless cores – to witness the very beginnings of massive star birth.

The team of astronomers from the United States, the United Kingdom, and Italy used ALMA to look inside these cores for a unique chemical signature involving the isotope deuterium to essentially take the temperatures of these clouds to see if stars had formed. Deuterium is important because it tends to bond with certain molecules in cold conditions. Once stars turn on and heat the surrounding gas, the deuterium is quickly lost and replaced with the more common isotope of hydrogen.

The ALMA observations detected copious amounts of deuterium, suggesting that the cloud is cold and starless. This would indicate that some counter force is forestalling core collapse and buying enough time to form a massive star. The researchers speculate that strong magnetic fields may be propping up the cloud, preventing it from collapsing quickly.

"These new ALMA observations reveal objects that are quite similar to the nurseries of Sun-like stars, but simply scaled-up by tens or a hundred times. This may mean that nature is more important than nurture when it comes to determining a star's size," concludes Tan.

These observations were conducted during ALMA's early science campaign. Future studies with ALMA's full array of 66 antennas will uncover even more details about these star-forming regions.



INFORMATION:

ALMA, an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.



The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.



ELSE PRESS RELEASES FROM THIS DATE:

Researchers find potential new treatment approach for pancreatic cancer

2013-12-21
Researchers find potential new treatment approach for pancreatic cancer Scientists from The University of Manchester -- part of Manchester Cancer Research Centre believe they have discovered a new way to make chemotherapy treatment more effective ...

Wayne State cholesterol study shows algal extracts may counter effects of high fat diets

2013-12-21
Wayne State cholesterol study shows algal extracts may counter effects of high fat diets Health Enhancement Products, Inc. (OTC.BB:HEPI.OB – News), in conjunction with Wayne State University's Department of Nutrition ...

Staph stoppers

2013-12-21
Staph stoppers New vaccine from University of Iowa protects against lethal pneumonia caused by staph bacteria University of Iowa researchers have developed a new vaccine that protects against lethal pneumonia caused by Staphylococcus aureus (staph) bacteria, including ...

A wrong molecular turn leads down the path to Type 2 diabetes

2013-12-21
A wrong molecular turn leads down the path to Type 2 diabetes Computing resources at the U.S. Department of Energy's (DOE) Argonne National Laboratory have helped researchers better grasp how proteins misfold to create the tissue-damaging structures that ...

UNL research raises concerns about global crop projections

2013-12-21
UNL research raises concerns about global crop projections 30 percent of world's corn, rice and wheat crop land may be 'maxed out' LINCOLN, Neb. — About 30 percent of the major global cereal crops – rice, wheat and corn – may have reached their maximum possible ...

Penn researchers grow liquid crystal 'flowers' that can be used as lenses

2013-12-21
Penn researchers grow liquid crystal 'flowers' that can be used as lenses A team of material scientists, chemical engineers and physicists from the University of Pennsylvania has made another advance in their effort to use liquid crystals as a medium for assembling ...

NASA sees powerful Tropical Cyclone Bruce staying away from land

2013-12-21
NASA sees powerful Tropical Cyclone Bruce staying away from land Tropical Cyclone Bruce continued to strengthen over wide open waters of the Southern Indian Ocean and NASA satellite data showed its eye had cleared of clouds. Bruce is forecast to stay away from ...

Religion is good for business shows Rotman study

2013-12-21
Religion is good for business shows Rotman study Toronto – Those looking for honest companies to invest in might want to check out businesses based in more religious communities, suggests a new paper from the University of ...

Not just the Koch brothers: New Drexel study reveals funders behind the climate change denial effort

2013-12-21
Not just the Koch brothers: New Drexel study reveals funders behind the climate change denial effort A new study conducted by Drexel University's environmental sociologist Robert J. Brulle, PhD, exposes the organizational underpinnings and funding behind the powerful ...

NASA satellites see Tropical Cyclone Amara affecting Rodrigues Island

2013-12-21
NASA satellites see Tropical Cyclone Amara affecting Rodrigues Island When NASA's Terra satellite passed over Tropical Cyclone Amara on December 20, its western quadrant was already moving over Rodrigues Island, Mauritius. Warnings are already in effect for the island, ...

LAST 30 PRESS RELEASES:

Toxic metals linked to impaired growth in infants in Guatemala

Being consistently physically active in adulthood linked to 30–40% lower risk of death

Nerve pain drug gabapentin linked to increased dementia, cognitive impairment risks

Children’s social care involvement common to nearly third of UK mums who died during perinatal period

‘Support, not judgement’: Study explores links between children’s social care involvement and maternal deaths

Ethnic minority and poorer children more likely to die in intensive care

Major progress in fertility preservation after treatment for cancer of the lymphatic system

Fewer complications after additional ultrasound in pregnant women who feel less fetal movement

Environmental impact of common pesticides seriously underestimated

The Milky Way could be teeming with more satellite galaxies than previously thought

New study reveals surprising reproductive secrets of a cricket-hunting parasitoid fly

Media Tip Sheet: Symposia at ESA2025

NSF CAREER Award will power UVA engineer’s research to improve drug purification

Tiny parasitoid flies show how early-life competition shapes adult success

New coating for glass promises energy-saving windows

Green spaces boost children’s cognitive skills and strengthen family well-being

Ancient trees dying faster than expected in Eastern Oregon

Study findings help hone precision of proven CVD risk tool

Most patients with advanced melanoma who received pre-surgical immunotherapy remain alive and disease free four years later

Introducing BioEmu: A generative AI Model that enables high-speed and accurate prediction of protein structural ensembles

Replacing mutated microglia with healthy microglia halts progression of genetic neurological disease in mice and humans

New research shows how tropical plants manage rival insect tenants by giving them separate ‘flats’

Condo-style living helps keep the peace inside these ant plants

Climate change action could dramatically limit rising UK heatwave deaths

Annual heat-related deaths projected to increase significantly due to climate and population change

Researchers discover new way cells protect themselves from damage

Rivers choose their path based on erosion — a discovery that could transform flood planning and restoration

New discovery reveals dopamine operates with surgical precision, not as a broad signal

New AI tool gives a helping hand to x ray diagnosis

New Leicester study reveals hidden heart risks in women with Type 2 Diabetes

[Press-News.org] Starless cloud cores reveal why some stars are bigger than others