Using NASA’s Hubble Space Telescope, the team took hundreds of high-resolution photos and compared the images pixel-by-pixel to identify the dimmest stars in the globular star cluster NGC 6397.
“The light from these faint stars is so dim that it is equivalent to that produced by a birthday candle on the Moon, as seen from Earth,” says Richer, lead investigator of the project, which was chosen over several thousand other proposals to gain almost five days access to Hubble.
The team surveyed two distinct stellar populations -- red dwarfs and white dwarfs -- in NGC 6397. Located in the southern constellation Ara, approximately 8,500 light-years away, NGC 6397 is the second closest globular star cluster to Earth.
At approximately eight per cent the mass of the Sun, the lowest mass red dwarfs are the least massive stars in the Universe still capable of burning hydrogen in their cores and supporting stable nuclear reactions.
White dwarfs are the burnt out remnants of more massive stars that died long ago. By measuring the temperatures of white dwarfs -- much like checking the temperature of smoldering coals in a campfire to estimate how long ago it was burning -- astronomers are able to determine the star’s age. This information provides important clues to the age of the globular cluster, which formed in the early Universe.
Analysing this relic population of white dwarfs is also the only way to calculate the original number of high-mass stars in the cluster.
“These stars, which died long ago, were among the first to have formed in the Universe,” says Richer, the world’s leading expert in using white dwarfs as a tool for dating globular clusters. “Pinning down their age narrows down the age range of the Universe.”
NB: Detailed results will be published in the Aug. 18 edition of the journal Science. For an advance copy of the paper, contact Natasha Pinol, AAAS / Science at 202.326.7088 or email@example.com.
Prof. Richer will present the team’s findings at an Aug. 17 press conference during the General Assembly of the International Astronomical Union (IAU) in Prague. For more information, visit http://www.astronomy2006.com.
Electronic images are available at http://hubblesite.org/news/2006/37/.
High-resolution photos of Prof. Richer and star cluster NGC 6397 is available at http://www.publicaffairs.ubc.ca/download/.Biography: Harvey B. Richer
Richer has been at the University of British Columbia since the early 1970s. He has received various awards and distinctions including: Canada-U.S. Fulbright Scholar (2005), Canada Council for the Arts Killam Fellowship (2001-03), and the Gemini Scientist for Canada (2000-03).
His research is largely focused on stellar astronomy and on what resolved systems of stars can tell us about dark matter, the age of the Universe, the dynamical evolution of stellar systems, and the formation of galaxies. To investigate these diverse subjects, he observes a wide range of objects, including nearby stars, open and globular star clusters, and the resolved components of our neighbouring galaxies.
To accomplish his research goals, he uses a variety of telescopes, particularly the Twin Gemini Telescopes, the Canada-France-Hawaii Telescope and the Hubble Space Telescope.
Randy Schmidt | EurekAlert!
New quantum liquid crystals may play role in future of computers
21.04.2017 | California Institute of Technology
Light rays from a supernova bent by the curvature of space-time around a galaxy
21.04.2017 | Stockholm University
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
Two researchers at Heidelberg University have developed a model system that enables a better understanding of the processes in a quantum-physical experiment...
Glaciers might seem rather inhospitable environments. However, they are home to a diverse and vibrant microbial community. It’s becoming increasingly clear that they play a bigger role in the carbon cycle than previously thought.
A new study, now published in the journal Nature Geoscience, shows how microbial communities in melting glaciers contribute to the Earth’s carbon cycle, a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
21.04.2017 | Physics and Astronomy
21.04.2017 | Health and Medicine
21.04.2017 | Physics and Astronomy