Thanks to the “gravitational microlent” technique, Hubble has identified an orphan planet of its star, comparing its surveys with those of 25 years ago.
In May 2023, the terrestrial telescopes of the Ogle project recorded a very short light flash in astronomical terms – just eight hours – called Ogle – 2023 -BLG -0524, attributable to a phenomenon of gravitational microlensing.
Ogle (Optical Gravitational Lensing Experiment) is a ambitious astronomical project Polish, started in 1992 and conducted by the University of Warsaw. Its main purpose is The study of the universe through the technique of “gravitational microlent”a method that exploits the curvature of light caused by the severity of massive objects to detect celestial bodies otherwise invisible. In this phenomenon, already foreseen by Einstein, a significant mass object acts as a lens, amplifying the light of a star or a galaxy further away while passing by them compared to our point of view here on Earth.
A unique case. What makes the case of Ogle – 2023 -BLG -0524 is the lucky randomness: the Space telescope Hubble had immortalized the same portion of heaven in 1997during another microlensing event. This has provided an observation base with a 25 -year interval – the longest ever used so far – to understand what the object that produced the gravitational lens was.
A “orphan” planet clue. The short duration of the event and the absence of a clearly visible star detected in the images of Hubble of 1997 and then in 2023 they directed astronomers to consider the possibility that to produce all this was an orphan planet. These worlds, expelled from their original systems, Vagano free in the Galaxy without stars guest. Perhaps even our solar system, to its early days, expelled of the planets who now wander orphans of their mother star, the sun.
Returning to recent discovery, the report explains that the team led by Mateusz Kapusta of the University of Warsaw has carried out careful research in the old visual “photographs”, not finding traces of any star close to the potential object-landing and therefore makes it a wandering or orphan planet. Based on data, The mass of the alleged planet oscillates between the Earth’s and that of Saturndepending on its position – if in the galactic disc or in the central bulb – which has not been defined so far.
The value of the archives. The study highlights the great potential of the observations stored: images made for different purposes, such as those of 1997, can prove to be decisive years later. However, Hubble – albeit powerful – showed its limits: the images allow you to exclude only brighter stars for genre telescopes, i.e. of magnitude 21.7 (remember that the higher the value, the less bright is the object), while weaker or red dwarf stars, may not appear in the observations.
Future perspectives. The study is a test bench for future missions. The James Webb Space Telescope, thanks to its sensitivity in the infrared, could identify much weaker stars and shed light on the nature of microlensing objects like this.
Even more ambitious is the Nancy Grace Roman mission, which will debut in 2027 e He will use the microlensing to probe our galaxy precisely in search of orphaned planets. According to forecasts, it could discover thousands of them, finally revealing the real abundance of these “Interstellar nomads”.
