A rich and complex planetary system for the star TOI-4010. The paper: “TOI-4010: A System of Three Large Short-period Planets with a Massive Long-period Companion” of M. Kunimoto (MIT) appeared on AJ)
To date (November 2023), we have confirmed the presence of 5539 exoplanets in 4128 planetary systems. These numbers indicate that, in the majority of cases, we have identified one planet per planetary system. This limitation is primarily due to observational constraints, as it remains challenging to detect small exoplanets with long orbital periods (distant from their stars several astronomical units, where 1 AU equals 150 million km, representing the average distance between Earth and the Sun).
However, there are noteworthy exceptions to this. One of the most known multiple exoplanetary systems is orbiting around the star Trappist-1, hosting six rocky planets, including three situated within the habitable zone (which is the region around a star where rocky planets may maintain temperatures suitable for liquid water on their surfaces). Another star hosting multiple planets is TOI-4010, a star with a mass of 0.8 solar masses and high metallicity (indicating an elevated abundance of chemical elements heavier than helium and hydrogen), which hosts three planets.
From the analysis of photometric observations obtained with the NASA satellite TESS and a comprehensive set of ground telescopes (essential for constructing the star light curve, representing the time variability of stellar luminosity), along with a series of 112 spectroscopic observations obtained using the HARPS-N spectrograph on the Telescopio Nazionale Galileo (critical for measuring stellar oscillations from equilibrium position using the radial velocity method), the team of researchers led by astronomer M. Kunimoto (Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology) has confirmed the existence of three planets around TOI-4010 and discovered an additional planet. Of particular interest is TOI-4010 b, with a mass of 11 Earth masses and a period of 1.3 days, situated in the “Neptunian deserts.” This term denotes the scarcity of known Neptunian planets with orbital periods between 1 and 4 days, likely due to intense stellar radiation incident on planets in close orbits, causing rapid evaporation of their atmospheres. TOI-4010 b may have retained much of its atmosphere due to its high metallicity, which would make such evaporation less efficient. TOI-4010 c has a mass of about 20 Earth masses and a period of 5.4 days, while TOI-4010 d is more massive (38 Earth masses) and has a longer period (14.7 days). The newly discovered object is more massive than the others, with a mass of about 692 Earth masses and an orbital period of 762 days, even though its physical parameters are still poorly constrained. The discovery is described in the paper “TOI-4010: A System of Three Large Short-period Planets with a Massive Long-period Companion“, recently published in The Astrophysical Journal. Among the long list of coauthors are the astronomers L. Affer and J. Maldonado from INAF – Astronomical Observatory of Palermo.
The figure (click here to visualize the image entirely) shows the period-radius diagram of known planets, with marked the “neptunian desert” and the position of TOI-4010 b, c, and d.
Mario Giuseppe Guarcello ( follow mariospiegacose) ( mariospiegacose) ( follow mariospiegacose)
Follow the Astronomical Observatory of Palermo on Facebok and on Instagram
Subscribe the Youtube channel of the Astronomical Observatory of Palermo