12.03.2020 change 12.03.2020

Astronomers Find Pulsating ‘Tear Drop’ Star 1,500 Light Years From Earth

An artistic rendering of HD 74423. Credit: Gabriel Pérez Díaz/IAC An artistic rendering of HD 74423. Credit: Gabriel Pérez Díaz/IAC

A new type of pulsating star in the shape of a ‘tear drop’ has been discovered by an international team off scientists led by researchers from the Nicolaus Copernicus Astronomical Center PAS in Warsaw.

The new star named HD 74423 was spotted in the Milky Way some 1,500 light years from earth, and is thought to be 1.7 times the mass of the Sun.

And unlike standard variable stars which change brightness and give the impression of ‘rhythmically pulsating’, the new star pulsates on just one side, giving it it’s distinct shape.

According to the research published in the latest issue of Nature Astronomy the star is being distorted by the gravitational pull of its nearest companion star.

Scientists have long-thought that the axis of a star’s pulsation can be moved by tidal forces.

But until now, there was no observational evidence that such objects actually existed.

By using the TESS satellite, which has been hunting for new planets since its launch in 2018, scientists were able to observe changes in brightness resulting from both the gravitational deformation of the star and pulsations.

It turned out that the pulsation amplitude very strongly depended on the angle, at which the star was observed (and thus its orientation in the binary system).

Co-author of the report, PhD student Paulina Sowicka, said that when binary stars revolve around each other, we see different parts of the pulsating star: sometimes it is its surface directed towards the companion, sometimes the outer surface.

The lead author of the publication is Professor Gerald Handler from the Nicolaus Copernicus Astronomical Center PAS in Warsaw.

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