UVIT of ISRO: Rare UV-Bright Stars spotted

The Astronomers have spotted massive hot UV-Bright stars in Milky Way Galaxy with the help of UVIT. UVIT is Ultra Violet Imaging Telescope. It is placed in Astrosat satellite. The Astrosat is the first multi wavelength space satellite of India.

UV-Bright Star: Recent Observation of UVIT

  • The Astronomers have successfully distinguished the UV-bright star cluster from relatively cooler red giant stars and other main sequence stars. More than thirty-four UV-bright stars were discovered using the UVIT.
  • From the images, the team also derived properties of the stars such as luminosities, temperature and radii. The derived properties of the stars were placed in Hertzsprung-Russel diagram. It is the diagram that shows relationship between stars’ absolute magnitudes and luminosities versus their effective temperatures (or stellar classification). The diagram was first created in 1910 by Ejnar Hertzsprung and Henry Norris Russell.

What is a UV Bright Star?

A UV-Bright Star is brighter than the horizontal branch and bluer than the red giant branch. According to the astronomers, the inner core of the stars spotted are almost exposed. This is making them extremely hot. They were evolved from a solar stage called “Horizontal Branch Stars”. Such stars do not have an outer envelope. These stars are in their late stages of evolution just like the sun. Apart from UVIT, the astronomers also used Gaia telescope and space telescope to identify the stars.


  • The Ultra Violet Imaging Telescope is a three in one imaging technology. It can observe in Near Ultraviolet, visible and far-ultraviolet wavelengths.
  • The UVIT has two telescopes. One works in visible range, that is, 320 nano metres to 550 nano metres. The other works in Near Ultraviolet wavelength, that is, 200-300 nano metres.
  • UVIT is three times better than GALEX of NASA. GALEX is Galaxy Evolution Explorer. It was an Ultraviolet Space Telescope launched in 2003 and decommissioned in 2013.

Earlier Observations of UVIT

  • So far UVIT has carried out 1166 observations of 800 unique celestial sources.
  • It has explored several star clusters and mapped large and small satellite galaxies near Milky Way Galaxy called Magellanic Clouds.


The Astrosat was launched in 2015. It was the first multi wavelength space observatory of India. It was launched to observe the universe in ultraviolet, visible and low and high energy X-rays. The mission has put ISRO in an exclusive club of nations that currently own space-based observatories. They are US, Japan, European Space Agency and Russia.



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