Astronomes have been for years now in search of the el Planet nine (sometimes also called planet x), a trans-Nettunian planet-that is, beyond the orbit of Neptune-whose presence seems necessary to explain the anomalous orbit of different objects in the most remote suburbs of the Solar System. A new studyled by Terry Long Phan of the Tsing Hua University of Taiwan, claims to have finally found This elusive object thanks to the comparison between the data of two infrared telescopes that have resumed the same regions of heaven 23 years from each other. Astronomes have sought objects whose data in these data movement is compatible with that expected by the planet nine in a period of 23 years, finding one in particular that seems to have theright identikit of planet nine. Different doubts However, they remain on the truthfulness of the discovery, since the authors do not consider the case that the detection is a false positive or an infrared galaxy not visible in one of the two catalogs used.
What is the planet nine
The existence of the planet nine It was proposed by Caltech’s astronomers Mike Brown and Konstantin Batygin In the 2016 To explain theanomalous orbit of some objects Trans-Nettunianithat is, positioned beyond the orbit of Neptune. In fact, it seems that these distant objects are influenced by the gravitational attraction of a huge and invisible body, much larger than the earth and positioned far beyond the orbit of Pluto. Although for years there have been several studies that have claimed to have found clues to its existence, so far there has not been No final test on the presence of this planet In the cold suburbs of the Solar System, not even using the most powerful telescopes at our disposal.
How the Planet candidate nine was found
The team led by Terry Long Phan of the TSing Hua University of Taiwan attempted to find the planet nine using one ingenious methodology. Astronomes have used i Archive data of two space telescopes sensitive to the wavelengths of the far infrared, IRAS and Akari. The use of the Afraoxy is advisable for the search for planet nine, since such a cold and distant world receives and reflects only a tiny amount of optical light.
The data of the IRAS and Akari telescopes cover the same portion of heavenbut have been obtained 23 years one from each other. This allowed astronomers to compare the images and seek those objects that are in this time span are moved to heaven of a quantity like that expected by a hypothetical planet nine. The researchers in particular searched for objects that have moved about 3 Arcominutes every year for 23 yearscompatible with what was expected for a mass planet between 7 and 17 times that of the earth and between 500 and 700 astronomical units, that is, between 75 and 105 billion km from us.
Initially the team found 13 candidate objects who had moved a quantity consistent with the expected orbit of the planet nine. After an in -depth selection process, which also included a visual inspection of the original images, astronomers have restricted the list to a valid candidatewhich shows a separation between the 42 and 69.6 Arcominuti (about twice the diameter of the full moon) and which never appears in the same position in two images taken in consecutive moments.
The criticisms of the study
Despite the exceptional nature of the discovery, the authors recognize that i data used are not enough To identify the object found such as planet nine and that more observations are necessary to confirm the discovery. To cool further the spirits thought about it Mike Brown himself, who, in a long post on the Social Blue Sky, raised different doubts about the robustness of the discovery.
The Caltech astronomer has in fact punished how researchers do not mention the probability that the object found by them be a false positivethat is, for example, different sources that are found in the right positions to be considered as the same object. The researchers also do not mention the possibility that objects that appear and disappear in a catalog may be Astrophysical sources which naturally vary in infrared brightness or the possibility that the object found not is a planet, but a galaxy Which shows the same infrared brightness awaited by a planet (the images have too low a resolution to distinguish the shape of a galaxy). Even more “worrying” is theabsence of an estimate of the orbit of the object found. Mike Brown, using the data available, found that the object would move on aorbit perpendicular to the solar system plancompletely disagreed with what is expected from the planet nine.
In short, the Hunt for planet nine continue And it is in full swing. According to many, our greatest hope of finding it lies in the telescope Vera Rubin That, starting this year, the southern sky will son every night in search of objects that vary in position and brightness, just as the elusive planet nine would do.
