Astrophysical fluid dynamics she pulls in her arms. These stars gradually slow down over the eons, but those bodies that are still spinning rapidly may emit radiation that from Earth appears to blink on and off as the star spins, like the beam of light from a turning lighthouse. This "pulsing" appearance gives some neutron stars the name pulsars. After spinning for several million years pulsars are drained of their energy and become normal neutron stars. Few of the known existing neutron stars are pulsars. Only about 1,000 pulsars are known to exist, though there may be hundreds of millions of old neutron
POlarization Emission of Millimeter Activity at the Sun of observing at 45 and 90 GHz comes from the necessity to determine the "upturn" frequency in the so-called "THz events": if the main radiation mechanism is synchrotron radiation from accelerated electrons emitting at chromospheric or coronal heights, it is expected a spectrum with a long and descending logarithmic tail towards millimeter wavelengths. In some cases this classical ("textbook") shape is broken and an "upturn" or "spectral reversion" is observed. Since the reversion or "upturn" frequency has been estimated around 50 to 100 GHz for the observed cases, the importance of POEMAS is justified. POlarization Emission of Millimeter Activity at