Pulsars help detect space weather disruptions triggered by Sun

Using uGMRT, astronomers record pulsar radio flashes once every 14 days and it was during one such observation in February 2019 that they chanced upon Coronal Mass Ejection (CME). One such disruption, resultant CME, was confirmed based on the abnormally-delayed radio signals received from PSRJ2145 – 0750, the pulsar source under uGMRT observation, on February 23, 2019.

CMEs — wave streams containing charged particles and plasma — emerge from the Sun and possess a great potential to disrupt space weather, affect satellite, telecommunications and power grids on Earth.

“The pulsar signal observed from this source on the following day, February 24, was noted to have a delay of about six times higher than what occurs normally. This excess delay was caused due to the highly electrically charged medium — present between the Earth and the Sun — which was a result of the CME event from the previous day,” said Prof Bhal Chandra Joshi, senior scientist at the TIFR — National Centre for Radio Astrophysics, Pune, who was a part of the study published recently in the journal of Astronomy and Astrophysics.

Joshi is one of the 20 astronomers associated with the Indian Pulsar Timing Array (InPTA) from Tata Institute of Fundamental Research, IIT-Roorkee, IIT-Hyderabad, Institute of Mathematical Sciences and Raman Research Institute, who were involved in this discovery.

Scientists say that when gravitational waves approach Earth, there is either an advancement or delay by a tiny measure, of the order of a few tens of microseconds, in this pulsar beam signal arriving over earth.

“We are aware of the standard delays in the arrival of the radio signals from the pulsar but since the signal from PSRJ2145 – 0750 arrived beyond this acceptable delay, it got scientists thinking. Other satellite observations confirmed a medium intensity CME on February 23, 2019,” added Joshi.

The InPTA astronomers further stated that solar cycles and Sun’s activity, either the maximum (solar activity is at its peak) or the minima (solar activity is at its lowest point) will now have to be factored in while studying pulsars.

This is because any change in the composition of the medium triggered by CMEs can also lead to deterioration in the accuracy of predicting radio flashes from the pulsars, they said.

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