In the extreme environment at the centre of our galaxy, a newly discovered star called S4714 orbits the supermassive black hole Sagittarius A*.

S4714 is just one of a group of stars that have now been discovered skimming Sgr A* on closer orbits than any other stars discovered previously.

Not only does this discovery suggest there are even more stars on daredevil orbits around our galaxy's supermassive black hole, it has given us the first candidates for a type of star originally proposed nearly 20 years ago - those that get so close to a black hole, they are 'squeezed' by its tidal forces.

For years, a star called S2 was regarded as the nearest star to the black hole.

At its closest approach, or periapse, its 16-year orbit brought it within around 18 billion kilometres of Sgr A*, the gravitational kick from this close approach accelerating the star to 3 percent of the speed of light.

After years of work, they've now discovered five new S stars even closer than S2 - S4711, S4712, S4713, S4714 and S4715.

S4711, a blue B-type star around 150 million years old, has an even shorter orbital period than S62; it goes around Sgr A* once every 7.6 years, with a periapse distance of 21.5 billion kilometres.

Although it doesn't skim as close, its shorter orbital period means it has the shortest mean distance to the black hole throughout its entire orbit that we've yet discovered.

Meanwhile, S4714 has a longer orbital period than S4711 - 12 years - but its orbit is extremely eccentric, meaning the ellipse shape is elongated; about as elongated as a stable orbit can get, actually.

During this close approach, the star speeds up to 24,000 kilometres per second, slowing down as it swings back out as far as 250 billion kilometres from the black hole.