Enormous advances in the techniques of observational astronomy have been made in recent decades, culminating today with an incredible array of observatories that are providing us with a detailed, diverse view of the Universe. These observations are the foundation of studies of the stars, and unexpected discoveries routinely drive research into new and exciting avenues.
Many of the observations described above are being made not only to improve our understanding of energetic, large-scale phenomena in the cosmos, but also as part of a search for our the cosmic origin of the subatomic nuclei comprising our bodies and our world.
For example, observations of heavy element abundances on the surfaces of old metal-poor stars that mirror the predictions of abundances from supernova r-process models suggest that these stars were exposed to the ashes of one or a few supernova explosions. Such observations are an essential ingredient in determining where the heavy elements were formed.
The interpretation of many astronomical observations requires a synergistic combination of the measurements of the properties and reactions of unstable nuclei (such as those we will pursue at FRIB), predictions of nuclear theories, data processing and evaluation work, and astrophysical simulations.
These pages will be devoted to observations of the exciting astrophysical phenomena that will be addressed by measurements at FRIB.
Today we have ground-based devices that enable us to detect:
- photons, by devices such as the Keck (shown above), SUBARU, and European Southern Observatory telescopes
- gravity waves from coalescing neutron stars, by the Laser Interferometer Gravity Observatory
- neutrinos from the sun and from supernovae by detectors at Kamiokande and the Sudbury Neutrino Observatory
- grains of meteorites via secondary mass ion spectroscopy
Discoveries relevant for FRIB astrophysics from such observatories include: measurements of elusive neutrinos shown to come from the direction of the sun and from supernovae 1987a; ultra-high precision analyses of small SiC grains inside meteorites that fell to earth that constrain s-process (and therefore r-process) abundances; and detection of r-process-like abundances on the surfaces of metal poor stars.
There are also orbital observatories, covering the entire electromagnetic spectrum, that are making measurements relevant for RIA astrophysics:
- gamma-rays by INTEGRAL
- X-rays by the CHANDRA X-ray Observatory and soon by the new Astro-EII satellite
- ultraviolet light by the Far Ultraviolet Spectroscopic Explorer
- visible light by the the Hubble Space Telescope
- infrared light by the Spitzer Space Telescope
- microwaves by the Wilkinson Microwave Anisotropy Probe
There are also specialized orbital missions such as STARDUST which is collecting bits of stardust to return for study in Earth-bound laboratories.
These observatories have been used, for example, to map the entire galaxy in gamma-ray intensity from the decay of one radioactive nuclide 26Al that is produced in exploding stars and other sites and to make multiple-wavelength observations of the remnant of the Cas A supernova explosion.
Progress in understanding the fascinating objects described above requires a close coupling of detailed observations with measurements with unstable nuclei at FRIB.Please contact us with suggestions of astronomical observation topics relevant to nuclear astrophysics research at FRIB.