An artist's impression of the star with its tidally locked red dwarf companion. GABRIEL PÉREZ DÍAZ (IAC)
A star that pulsates on just one side was discovered in the Milky Way 15,000 light-years away from Earth. The improvement of the technology used in listening to the inside of the stars' beating heart made the scientists to expect to find more similar systems as this was the first of its kind to be discovered.
Pulsating Variable Stars
The main sequence stars have an almost unchanging luminosity. However, some giant and supergiant stars vary in luminosity because they pulsate in and out. The time between peaks of brightness or the star's luminosity fluctuations can range from a few hours to a few days.
The best examples of pulsating variable stars are Cepheid stars and RR Lyrae stars. The variation in their luminosity results from the fact that they pulse in and out.
Cepheid star is a type of star that evolved from the main sequence into the Cepheid instability strip. The changes in its brightness with a well-defined stable period amplitude were produced by the Cepheid stars pulsating radially, varying in temperature and diameter.
On the other hand, RR Lyrae stars are low metallicity stars that begin their lives with a mass and size similar to that of our Sun. They then become RR Lyrae stars during the later part of a star's evolution -the red giant phase, and typically ages around 10 billion years.
The Teardrop Star
The star which is about 1.7 times the size of the Sun is known as HD74423 has become a teardrop-shaped star because of the gravity of its neighbor, a much smaller red dwarf. They are two halves of a binary system and it was only after 40 years of searching did the astronomers spotted a first-of-its-kind star that pulsates on just one side. Other stars pulsate at its rhythmic rates.
This discovery was first spotted by amateur astronomers while they are reading through the data from NASA's Transiting Expoplanet Survey Satellite (TESS), which is dedicated to hunting planets. Upon noticing distortions in the larger star's gravity, they prompted others who are also monitoring the phenomenon.
According to David Jones the study's co-author from the University of Sydney, they saw different parts of the pulsating star as the binary star orbit with each other. At times the astronomers would see the side that points towards the companion star, and sometimes the outer face.
The HD74423 is in a binary system with a red dwarf which distorts the oscillations with its gravitational pull. This is due to the orbital period of the binary system which is two days. Although scientists have long known about pulsating stars, the case with the teardrop star is a new phenomenon.
Other discoveries by amateur astronomers
The discovery of the teardrop star may have been one of the fascinating discoveries by astronomers around the globe today. But there are more recent discoveries among the cosmos that are worth mentioning also.
For example, a 77-year old amateur astronomer recently helped discover a double nucleus galaxy. His name is Allen Lawrence, a retired engineer who used infrared images from NASA's Wide-field Infrared Survey Explorer to reveal the double nucleus galaxy.
Also, just recently NASA has announced that a 17-year old summer intern made an incredible planet discovery. Wolf Cukier, who had just finished his junior high at Scarsdale High School in New York made an incredible find while sifting through variations in star brightness captured by the space agency's TESS uploaded to the Planet Hunters TESS citizen science project.
It turns out TOI 1338 after all is a planet; it is the first circumbinary planet or a world orbiting two stars and is about 6.9 times larger than Earth, which means that its size is between Saturn and Neptune.
