What Is It: XPoSat: ISRO’s X ray eye in the sky

At 9.10 am on the first day of 2024, the Indian Space Research Organisation will launch XPoSat, short for ‘X ray Polarimeter Satellite’. Once launched, the satellite will study X rays emitted by phenomena in space and their polarisation from earth orbit. X rays are electromagnetic radiation whose wavelength is 0.01 10 nanometres (where 1 nanometre is one billionth of a metre), corresponding to energies of 100 100,000 electron volt (eV).

Electromagnetic radiation is characterised by an electric field and a magnetic field vibrating perpendicular to each other. The polarisation of electromagnetic radiation refers to the orientation of these two fields as the radiation moves through space. X rays can be polarised when they get scattered.

For example, when an X ray travelling through space encounters an atom, the electric field of the X ray can energise an electron, which will then emit a photon. Since X rays are also photons, the new photon will give the impression that an X ray photon has been scattered. Polarised X rays are also produced when the path of a fast moving charged particle is bent by a magnetic field.

Studying these X rays can reveal which way the magnetic field is pointing, and tracking how these X rays evolve in time can reveal many things about the body producing such fields, like a pulsar. The XPoSat satellite has two payloads to make these measurements. POLIX will study X rays with energy 8 30 keV emitted by around 40 astronomical sources in five years.

XSPECT will study X rays with energy 0.8 15 keV and track changes in continuous X ray emissions. COMMents SHARE Copy link Email Facebook Twitter Telegram LinkedIn WhatsApp Reddit ISRO / space programme.