TOI-1846 b: TESS Discovers a New Super-Earth Orbiting a Nearby M Dwarf Star
NASA’s Transiting Exoplanet Survey Satellite (TESS) has made another remarkable discovery: a new super-Earth exoplanet named TOI-1846 b. This alien world orbits a nearby M dwarf star and stands out due to its size and mass, being about twice as large and four times as massive as Earth
Key Facts About TOI-1846 b
| Feature | Value |
|---|---|
| Planet Name | TOI-1846 b |
| Host Star | TOI-1846 (M dwarf) |
| Distance from Earth | ~154 light-years (47 parsecs) |
| Planet Radius | 1.79 ± 0.07 Earth radii |
| Planet Mass | 4.4 (+1.6/−1.0) Earth masses |
| Orbital Period | 3.93 days |
| Orbital Distance | 0.036 AU (~5.4 million km) |
| Equilibrium Temperature | 589 ± 20 K (approx. 295°C) |
| Density | 4.2 g/cm³ |
| Host Star Radius | 0.41 solar radii |
| Host Star Mass | 0.40 solar masses |
| Host Star Temperature | 3568 ± 44 K |
| Host Star Age | ~7.2 billion years |
Discovery and Validation
- TESS detected periodic dips in brightness from the star TOI-1846, indicating a possible transiting planet.
- Follow-up ground-based photometric and spectroscopic observations confirmed the planetary nature of the signal1.
- High-resolution imaging ruled out background stars or stellar companions as the source of the transit signal.
What Makes TOI-1846 b Special?
- Super-Earth in the Radius Valley: TOI-1846 b’s size places it in the “radius valley,” a range where planets are rare due to atmospheric loss from stellar radiation. Its density suggests a rocky, potentially water-rich composition.
- Short Orbit: The planet completes an orbit around its star every 3.93 days, much closer than Mercury is to our Sun.
- M Dwarf Host: The host star is a cool, dim red dwarf, making it easier to detect planets in close orbits due to the star’s low luminosity.
Scientific Implications
- Water-Rich World: Based on its density and position in the radius valley, TOI-1846 b is likely a water-rich super-Earth, possibly with a secondary atmosphere.
- Exoplanet Demographics: Its discovery helps astronomers understand the distribution of rocky versus gaseous planets in close orbits, and the effects of stellar radiation on planetary atmospheres.
The Role of TESS
- TESS has revolutionized exoplanet discovery by monitoring the brightness of over 200,000 stars.
- With more than 7,600 exoplanet candidates and over 600 confirmed, TESS continues to expand our knowledge of planetary systems beyond our own.
The discovery of TOI-1846 b adds a fascinating new member to the growing family of super-Earths. Its proximity, size, and composition make it a valuable target for future studies on planetary formation, atmospheric evolution, and the potential for habitability in M dwarf systems.