TOI-2587 A b
TOI-2587 A b is a hot Jupiter orbiting TOI-2587 A in the constellation Monoceros. It lies about 1,219 light-years from Earth and was discovered in 2023 using the transit method.
How Big Is TOI-2587 A b?
TOI-2587 A b has a radius of 12.07 times that of Earth, or 1.08 times the radius of Jupiter. Its mass is 69.3 times that of Earth, giving it a density of 0.22 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is TOI-2587 A b in the Habitable Zone?
TOI-2587 A b orbits inside the inner edge of the habitable zone of TOI-2587 A. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of TOI-2587 A: 1.293–3.047 AU (conservative: 1.637–2.889 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on TOI-2587 A b
The equilibrium temperature of TOI-2587 A b is about 1,445 K (1,172 °C) — hot enough to melt many metals. This estimate ignores any atmosphere, which could change surface temperatures dramatically — Earth's greenhouse effect adds about 33 °C. It receives 728 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on TOI-2587 A b — one full orbit around TOI-2587 A — lasts 5.46 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.064 AU — closer to its star than Mercury is to the Sun.
How Was TOI-2587 A b Discovered?
TOI-2587 A b was discovered in 2023 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-2587 A b?
TOI-2587 A b is 1,218.8 light-years (373.7 parsecs) from Earth. Light arriving here tonight left the planet about 1,219 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 21,450,880 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-2587 A b scores 0.07, ranking #4,796 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: TOI-2587 A
TOI-2587 A b belongs to a system of 2 stars; it orbits TOI-2587 A.
TOI-2587 A
- Surface temperature
- 5,760 K (Sun: 5,772 K)
- Mass
- 1.15 M☉
- Radius
- 1.73 R☉
- Luminosity
- 2.9600 L☉
- Age
- 6.7 billion years (Sun: 4.6)
Planetary System
TOI-2587 A b is the only planet known to orbit TOI-2587 A so far.
TOI-2587 A b — Complete Data
| Radius | 12.072 Earth radii (1.077 Jupiter radii) |
|---|---|
| Mass | 69.29 Earth masses (0.218 Jupiter masses) |
| Density | 0.22 g/cm³ (Earth: 5.51) |
| Orbital period | 5.46 days |
| Orbital distance | 0.064 AU |
| Equilibrium temperature | 1,445 K (1,172 °C) |
| Stellar irradiation | 728.00× Earth |
| Earth Similarity Index | 0.07 |
| Distance from Earth | 1,218.8 light-years (373.7 parsecs) |
| Constellation | Monoceros |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2023 |
Data: NASA Exoplanet Archive, last updated 2023-02-27. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-2587 A b
Is TOI-2587 A b habitable?
No — TOI-2587 A b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is TOI-2587 A b?
TOI-2587 A b is about 1,219 light-years from Earth in the constellation Monoceros. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 21,450,880 years to get there.
How big is TOI-2587 A b compared to Earth?
TOI-2587 A b has 12.07 times the radius of Earth and about 69.3 times its mass.
How long is a year on TOI-2587 A b?
One orbit around TOI-2587 A takes 5.5 Earth days — short enough that 67 of its years would fit into one Earth year.
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