What Are the Unique Features of This Super-Earth?
Using the Transiting Exoplanet Survey Satellite (TESS) – a NASA space telescope system – an international team of astronomers has discovered two new exoplanets orbiting a cool orange dwarf star known as TOI-836. TOI-836 is located relatively close to our Sun.
The host star TOI-836 is approximately 90 light-years away from Earth. This star has a low metallicity. Its age is estimated to be 5.4 billion years, with a mass and radius about one-third that of the Sun.
During observations, TESS detected periodic dimming of TOI-836’s light, corresponding to the presence of orbiting planets.
The newly discovered worlds are classified as a super-Earth and a sub-Neptune. The findings were reported in a paper published in August 2022 on arXiv.org.
Two Exoplanets Near the Solar System: One Super-Earth and One Sub-Neptune
TESS is conducting a survey of approximately 200,000 of the brightest stars near the Sun, aiming to search for exoplanets (planets outside the Solar System). To date, it has identified over 5,800 candidate exoplanets, of which 233 have been confirmed.
Now, a team of astronomers led by Faith Hawthorn from the University of Warwick, UK, has confirmed the two new exoplanets monitored by TESS. They report that transit signals have been identified in the light curve of TOI-836 – a dwarf star located about 90 light-years away from us.
TESS’s mission is to explore new Earths and super-Earths in deep space. Source: NASA
The planetary nature of these signals has been confirmed through subsequent observations using the Characterizing Exoplanet Satellite (CHEOPS) of the European Space Agency (ESA) and various ground-based facilities.
“In this paper, we presented the TOI-836 system and the discovery of its two planets, TOI-836b and TOI-836c“ – the researchers wrote in the paper.
The first exoplanet is named TOI-836b. It is closer to the host star and is classified as a super-Earth. TOI-836b has a radius 1.7 times that of Earth and a mass 4.5 times that of our planet, with an average planetary density of 5.02g/cm3.
TOI-836b’s orbit is just 6 million km from its star, taking only 3.8 days to complete one orbit. The equilibrium surface temperature of the exoplanet TOI-836b is estimated to be 500 degrees Celsius.
Illustration of an exoplanet’s movement around its host star. (Source: NASA / JPL-Caltech)
| Super-Earths are planets that have a mass greater than Earth’s but do not exceed that of Neptune. Although the term “super-Earth” refers to the planet’s mass, astronomers also use it to describe planets larger than Earth but smaller than so-called mini-Neptunes (with radii from 3 to 4 times that of Earth). |
The second exoplanet is named TOI-836c – regarded as a sub-Neptune. Its radius is approximately 2.6 times that of Earth, and its mass is over 9.6 times that of our planet, with an average planetary density of 3.06 g/cm3, indicating a significant presence of light elements in its composition.
TOI-836c’s orbit is at a distance of about 11.2 million km from its star, completing one orbit in 8.6 days. The equilibrium surface temperature of the exoplanet is estimated to be 390 degrees Celsius.
The host star TOI-836 is a 5.4 billion-year-old dwarf star, about 33% smaller and lighter than the Sun. It has an effective temperature of about 4,552 K and its metallicity is estimated to be -0.284.
Two newly discovered exoplanets orbiting a dwarf star named TOI-836, located about 90 light-years from the Sun. One is a super-Earth, and the other is a sub-Neptune. (Source: News.trenddetail).
Astronomers note that significant variations in the transit timing of their observations of TOI-836c may indicate the presence of a non-transiting third planet in the studied system.
They concluded, “However, we did not find the transit of a third planet in our current photometric dataset or any signs of additional periodic signals in our current radial velocity data.”
Also related to the ongoing search for exoplanets by TESS, NASA has officially announced the discovery of an exoplanet – a super-Earth – led by an international team of scientists from the University of Montreal (Canada).
This super-Earth is named TOI-1452b, located in the Draco constellation, about 100 light-years away from us.
Illustration of the exoplanet TOI-1452b. (Source: Benoit Gougeon, Université de Montréal).
TOI-1452b orbits a binary star system. It is about 70% larger than Earth and weighs five times more, with a density that suggests the possibility of a very deep ocean. The exoplanet TOI-1452b completes a full orbit around its star (TOI-1452) every 11 days, equivalent to one “year” on TOI-1452b.
To further observe TOI-1452b, scientists are waiting for the James Webb Space Telescope to “step in” for a definitive conclusion about the “vast watery world” and temperate conditions of TOI-1452b.
