TOI-1749 d
TOI-1749 d is a super-Earth orbiting the M0 V star TOI-1749 in the constellation Draco. It lies about 325 light-years from Earth and was discovered in 2021 using the transit method.
How Big Is TOI-1749 d?
TOI-1749 d has a radius of 2.52 times that of Earth. Its mass is 15.0 times that of Earth.
Is TOI-1749 d in the Habitable Zone?
TOI-1749 d orbits inside the inner edge of the habitable zone of TOI-1749. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of TOI-1749: 0.212–0.538 AU (conservative: 0.269–0.510 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on TOI-1749 d
The equilibrium temperature of TOI-1749 d is about 533 K (260 °C) — hotter than anywhere on Earth. This estimate ignores any atmosphere, which could change surface temperatures dramatically — Earth's greenhouse effect adds about 33 °C.
Orbit and Year Length
A year on TOI-1749 d — one full orbit around TOI-1749 — lasts 9.05 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.071 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.06).
How Was TOI-1749 d Discovered?
TOI-1749 d was discovered in 2021 using the transit method, with observations from Transiting Exoplanet Survey Satellite (TESS).
The transit method watches a star for the tiny, regular dip in brightness that occurs when a planet crosses in front of it. The depth and timing of these dips reveal the planet's size and orbital period.
How Far Away Is TOI-1749 d?
TOI-1749 d is 324.7 light-years (99.6 parsecs) from Earth. Light arriving here tonight left the planet around the year 1702. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 5,714,720 years to make the journey.
Earth Similarity Index
The Earth Similarity Index (ESI) scores how physically similar a planet is to Earth, from 0 to 1, based on radius, density, escape velocity and surface temperature. TOI-1749 d scores 0.32, ranking #1,082 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: TOI-1749
TOI-1749
- Spectral type
- M0 V
- Surface temperature
- 3,985 K (Sun: 5,772 K)
- Mass
- 0.58 M☉
- Radius
- 0.55 R☉
- Age
- 0.8 billion years (Sun: 4.6)
The TOI-1749 Planetary System
TOI-1749 d is one of 3 known planets in the TOI-1749 system. Its siblings:
- TOI-1749 b (Super Earth)
- TOI-1749 c (Super Earth)
TOI-1749 d — Complete Data
| Radius | 2.520 Earth radii (0.225 Jupiter radii) |
|---|---|
| Mass | 15.00 Earth masses (0.047 Jupiter masses) |
| Orbital period | 9.05 days |
| Orbital distance | 0.071 AU |
| Eccentricity | 0.062 |
| Equilibrium temperature | 533 K (260 °C) |
| Earth Similarity Index | 0.32 |
| Distance from Earth | 324.7 light-years (99.6 parsecs) |
| Constellation | Draco |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2021 |
Data: NASA Exoplanet Archive, last updated 2021-07-26. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-1749 d
Is TOI-1749 d habitable?
No — TOI-1749 d orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is TOI-1749 d?
TOI-1749 d is about 325 light-years from Earth in the constellation Draco. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 5,714,720 years to get there.
How big is TOI-1749 d compared to Earth?
TOI-1749 d has 2.52 times the radius of Earth and about 15.0 times its mass.
How long is a year on TOI-1749 d?
One orbit around TOI-1749 takes 9.0 Earth days — short enough that 40 of its years would fit into one Earth year.
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