Astronomy has unveiled some of the most impressive results: two Earth-sized Exoplanets orbiting a very nearby star called HD 101581. We have NASA’s Transiting Exoplanet Survey Satellite (TESS) and ground-based observations to celebrate for this exciting achievement. It adds two more members to the catalog of significantly increasing exoplanets that are likely to have potential significance in understanding planetary systems beyond our own.
Recent discoveries: HD 101581 b and c, Earth-like bodies with scorching temperature
The latest exoplanets discovered are two newly supported objects called HD 101581 b and HD 101581 c, which are notable for being similar in size to Earth and proximity to their host star. The closest of the two, HD 101581 b, has a radius of 0.956 Earth radii and a maximum mass of 3.6 Earth masses.
It takes only 4.47 days for the planet to orbit its host star, at only 0.046 AU (astronomical units). This tightly packed arrangement causes the planet to have an equilibrium temperature of a searing 834 K, or 561°C. The slightly more distant HD 101581 c has a rather near radius of 0.99 Earth radii and a maximum mass of 4.2 Earth masses.
Nevertheless, it has an equilibrium temperature of 747 K (474 °C) and the planet swoops by every 6.21 days at a distance of 0.057 AU. The dimensions and masses of both planets suggest they are Earthly-terrestrial. Interestingly, astronomers have discovered a signal that could be attributed to a third planet in the system, which will be named TOI-6276.03. If proven to exist, this planet would be coequal in dimensions with a radius of approximately 0.98 Earth radii and an orbital period of 7.87 days, thus establishing the case of considering HD 101581 a three-planet system.
The K-Dwarf HD101581 is a nice candidate for an exoplanet search
HD 101581, also designated TOI-6276, refers to a K-dwarf star that resides at a distance of around 41.7 light years within the constellation of Leo. This star, which has been existing for approximately 7 billion years, has an average radius and mass equal to about 0.63 and 0.74 times that of the typical sun, respectively.
With an effective temperature of around 4634 K, HD 101581 is a very cool and dim star, making it an exceptionally good candidate for closely studying exoplanets. HD 101581 is the brightest currently known star which has multiple transiting planets with sizes below 1.5 times the radii of the Earth and, at about 7.77 in V-band magnitude, makes for one of the brightest stars in these categories. This, in turn, brings it into focus for atmospheric characterizations and comparison studies of small rocky planets.
Peas in a pod: HD 101581 is an amazing compact multi-planet system that wows astronomers
That proves success even more for TESS, having discovered over 7,300 candidate exoplanets since 2018 from which, 589 are confirmed, with the planets of HD 101581 being uniquely highlighted by their near-resonant orbits and sizes.
The system architecture is rather that of “peas-in-a-pod,” where planets are equally spaced and alike in measure, a mechanism that can be observed in many compact multi-planet systems. Furthermore, the close distance of these planets from their respective stars has created a good setup for seeing the effect of stellar radiation on the planetary atmosphere.
The extreme equilibrium temperatures are very unlikely to allow any liquid water to exist on the planets, but they could still provide some key information on planetary formation and evolution in extreme conditions. The finding on the two Earth-magnitude exoplanets revolving about HD 101581 seems to add to the growing list of milestones being identified in the already well-initiated quest for a grasp of how planetary systems differ from one another.
Compact orbits coupled with a bright host star give these planets the appearance of tantalizing targets for atmospheric studies and future observations. HD 101581 is one more system reminding us of the never-ending possibilities before us as we explore the universe and the different and intricate architectures that define it.
