Indian finds X-rays from the rings of Saturn
NASA scientist Anil Bhardwaj has become the first to report on X-rays from the rings of Saturn, writes Lalit Jha.india Updated: Aug 27, 2005 11:19 IST
A few months after discovering that the planet Saturn acts as a "diffused mirror" for solar X-rays, scientist Anil Bhardwaj in his latest findings has revealed that its rings sparkle with X-rays.
Bhardwaj, a planetary scientist from the Indian Space Research Organisation (ISRO) working at the National Aeronautics and Space Administration (NASA) has, in process, probably become the first scientist to report on X-rays from the rings of Saturn.
At present Bhardwaj is on the prestigious National Academy of Science Fellowship at the NASA's Marshall Space Flight Centre, Huntsville, Alabama. Rings of Saturn, first seen in 1610 by Galileo Galilei are one of the most fascinating objects in our Solar system.
"Calculations suggest that the fluorescent scattering of solar X-rays by oxygen atoms present in the water (H2O) icy ring material is the main mechanism of production of the rings X-rays," Bhardwaj said. Rings are known to be made of mostly water.
"Some contributions can come from the icy-dust over the rings too," said Bhardwaj, who used the prestigious Chandra X-ray Observatory of the NASA for his study of the planet.
Giving details of his latest findings, Bhardwaj said the likely source for this radiation was the fluorescence caused by the solar X-rays striking oxygen atoms in the water molecules that comprise most of the icy rings.
Bhardwaj, who is actively involved in the Chandrayaan-I mission, said his latest findings suggests that Saturn's ring shine in X-rays due to scattered solar radiation.
"Our observations suggest that solar UV-X-ray radiation plays an important role in the physical and chemical processes in the rings of Saturn," he said.
"Another important aspect of this study is that one can even study distribution of H2O ice in Saturn rings, but the signal to noise ratio is very low to do such study," he said.
Bhardwaj said, the X-rays in the Saturn ring mostly come from the B ring, which is about 25,000 km wide and is about 40,000 km above the surface of the planet.
"There is some evidence for a concentration of X-rays on the morning side of the rings," he said, adding that the one possible explanation for this concentration is that the X-rays are associated with optical features called spokes, which are largely confined to the dense B ring and most often seen on the morning side.
According to Bhardwaj, the spokes, which appear as radial shadows in the rings, are due to transient clouds of fine ice-dust particles which are lifted off ring surface, and typically last an hour or so before disappearing.
"Higher X-ray brightness on the morning side of the rings could be due to the additional solar fluorescence from the transient ice clouds that produce the spokes," he said.
Bhardwaj, who came to US on this prestigious fellowship, in January 2004, was at the Space Physics Laboratory of the ISRO's Vikram Sarabhai Space Centre, Thiruvanathapuram.
He did his B Sc (Hons) and M.Sc in Physics from Lucknow University and Ph D in Physics (Space and Planetary Science) from the Institute of Technology, the Banaras Hindu University. In 1993, Bhardwaj joined ISRO as a senior research scientist.