X-ray Polarimeter Satellite (XPoSat)

The  Indian Space Research Organisation is collaborating with Raman Research Institute to construct an X-ray polarimeter satellite (XPoSat) which will study various dynamics of bright astronomical X-ray sources in extreme conditions. This is an important topic for the IAS exam science and technology segment.

X-ray polarimeter satellite (XPoSat):

• The X-ray polarimeter satellite (XPoSat) will be launched in the later part of this year.
• Apart from NASA’s Imaging X-ray Polarimetry Explorer (IXPE) which was launched in 2021, XPoSAT is the second polarimetry mission in the world.
• Also, the X-ray polarimeter satellite (XPoSat) is India’s first polarimetry mission to various dynamics of bright astronomical X-ray sources in extreme conditions.
• The payload of an X-ray polarimeter satellite (XPoSat) is composed of POLIX (Polarimeter Instrument in X-rays) which is the primary payload and XSPECT (X-ray Spectroscopy and Timing) payload.
• POLIX t can observe about 40 bright astronomical sources of different categories during the planned five-year XPoSat mission.
• The XSPECT (X-ray Spectroscopy and Timing) payload will observe several types of sources, such as X-ray pulsars, blackhole binaries, low-magnetic field neutron stars, etc and give spectroscopic information (on how light is absorbed and emitted by objects). 
• Imaging X-ray Polarimetry Explorer (IXPE) consists of three telescopes each of which will contain a light-weight X-ray mirror and one detector unit. The telescopes will help to observe the polarized X-rays from neutron stars and supermassive black holes.
• Thus by measuring polarization using telescopes the origin of the light source and the geometry and inner workings of the light source can be understood.

X-Rays in space:

• Hotter objects will emit a shorter wavelength of peak emission and the temperature of an object determines the emission of the wavelength of radiation.
• X-rays have shorter wavelengths in the range of  0.03 and 3 nanometers which is equivalent to the size of a single atom of many elements and X-rays also have higher energy.
• X-rays come from different types of objects such as pulsars, galactic supernova remnants, and black holes which are millions of degrees Celsius. X-rays originate from these objects as a result of complex physical processes which are difficult to understand.
• X-rays are composed of moving electric and magnetic waves whose peaks and valleys move in a random direction. However Polarised light is more organised with two types of waves vibrating in the same direction.
• One of the applications of polarised lenses is that fishermen use them to reduce glare from sunlight when they are near water.

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