New type of pulsating ‘tear drop’ star found 1,500 light years from earth

The star HD74423 orbits close to a red dwarf star, which is pulling it into a teardrop shape and causing unusual pulsation patterns. Gabriel Pérez Díaz (IAC)

A team of international scientists under the lead of the Nicolaus Copernicus Astronomical Centre in Warsaw has discovered a new type of star that pulsates on just one side.

The tear-drop-shaped star was discovered in the Milky Way some 1,500 light years from earth. Named HD74423 it is estimated to be 1.7 times the mass of the sun.

It has been known for many years that stars can pulsate, with even the sun getting in on the act from time to time, but until now no star had been seen pulsating on just one hemisphere although scientists had suspected that such a phenomena might exist.

The star was discovered after scientists went through information gathered by Nasa’s TESS satellite, which has been hunting for new planets since its launch in 2018.NASA

The star was discovered after scientists went through information gathered by Nasa’s TESS satellite, which has been hunting for new planets since its launch in 2018.

"The exquisite data from the TESS satellite meant that we could observe variations in brightness due to the gravitational distortion of the star as well as the pulsations," said Professor Gerald Handler from the Nicolaus Copernicus Astronomical Centre, and the lead author of a report on the star published in latest issue of Nature Astronomy.

Professor Gerald Handler from the Nicolaus Copernicus Astronomical Centre, and the lead author of a report on the star said by analysing satellite data they “could observe variations in brightness due to the gravitational distortion of the star as well as the pulsations.”users.camk.edu.pl

They found that one half of the star appeared to be pulsating more than the other half. The reason for this is probably because HD74423 has a small red dwarf star as a close companion. 

The smaller star can distort its larger companion with its gravitation pull, thus making pulsate on one side only. Along with the pulsation the gravitational pull of the dwarf can also distort the shape of the star, pulling it into a tear-drop shape.

The team of scientists believe that there are other stars that share the same properties of HD74423 lurking in the depths of space, waiting to be discovered.