Discovery [1] | |
---|---|
Discovered by | Kemmer et al. [2] |
Discovery date | 2022 |
Transit | |
Designations | |
Gliese 3929 b, TOI 2013 b, G 180-18 b [3] | |
Orbital characteristics [4] | |
0.0252±0.0005 AU | |
Eccentricity | 0 (fixed) |
2.616 d | |
Inclination | 88.442 °±0.008 ° |
Star | GJ 3929 |
Physical characteristics [4] | |
Mean radius | 1.09±0.04 R🜨 |
Mass | 1.75+0.44 −0.45 M🜨 |
Mean
density | 7.3±2.0 g/cm3 |
Temperature | 568±6 K (295 °C) |
GJ 3929 b (Gliese 3929 b, TOI-2013 b) is a confirmed exoplanet located 52 light-years away orbiting the red dwarf star GJ 3929. [3] It is an Earth-sized planet, having a radius only 9% larger than that of Earth. [4] It orbits its star at a distance of 0.0252 astronomical units (3,770,000 km), being located in the Venus zone of its star, and completes one orbit around it every 2 days and 15 hours. [4] Because of the proximity of its star, and its low mass, GJ 3929 b is classified as a Venus-like planet, having an equilibrium temperature of around 300 °C and receiving planetary insolation 17 times more intense than Earth receives from the Sun. [4]
Initially, the radius of GJ 3929 b was calculated at 1.15±0.04 R🜨, and its mass at 1.21±0.42 M🜨, giving a density of 4.4±1.6 g/cm3. [5] Later, observations using the NEID spectrometer on the WIYN 3.5 m Telescope measured the planet's mass to be 1.75±0.45 M🜨; and observations using the ARCTIC imager, plus photometry from TESS and LCOGT, constrained the planet's radius to 1.09±0.04 R🜨, this time giving a higher density of 7.3±2 g/cm3 (about 33% larger than Earth's [a]). [4] The characteristics of this planet make it similar to Earth in terms of mass and radius.
GJ 3929 b orbits its star at a distance of 0.0252 astronomical units (3,770,000 km), which makes it located in its host star's Venus zone, a region where rocky planets would have runaway greenhouse conditions like Venus. [4] GJ 3929 b completes an orbit around its star every 2 days, 14 hours and 47 minutes (2.616 days). [4]
As a terrestrial planet that orbits in the Venus zone of its star, GJ 3929 b classifies as a Venus-like planet, having a planetary equilibrium temperature of 295 °C and receiving planetary insolation 17 times greater than that of Earth receives from the Sun. [4]
The high density of GJ 3929 b does not suggest a dense atmosphere. [4] Atmospheric scenarios such as a thin atmosphere of volatiles, a thin atmosphere of silicate enriched in refractory elements, or even no atmosphere at all are plausible. [4] Due to its proximity to its star, GJ 3929 b has probably already lost much of its atmosphere since its formation. [4]
GJ 3929 b is an excellent planet for atmospheric study with the James Webb Space Telescope. [4] [5] The study of this planet's atmosphere can help reveal the evolutionary history of its planetary system, and provide more information about planetary formation models. [4]
GJ 3929 b was discovered by a team of astronomers led by Jonas Kermer, from the Heidelberg University in Germany. [2] They reported a transit signal identified in the host star ( GJ 3929)'s light curve detected by NASA's Transiting Exoplanet Survey Satellite (TESS). [2] Afterwards, the planetary nature of this transit signal was confirmed using radial velocity observations with the CARMENES spectrograph, in addition to transit observations made with SAINT-EX and LCOGT. [5] [2] The discovery was announced in 2022. [1]
The radial velocity observation with CARMENES also helped discover another planet in the planetary system, GJ 3929 c, a sub-Neptune detected by radial velocity. [5]
GJ 3929 is a red dwarf of spectral type M3.5V [7] that is located 51.6 light years from Earth, in the constellation Corona Borealis. [3] [note 1] This star is smaller, cooler and less luminous than the Sun, having a radius of 0.32 R☉, an effective temperature of 3,384 K (3,111 °C) and a luminosity equivalent to 1% of solar luminosity. [4] Its age is estimated between 2.2 and 11 billion years. [4]
The star also hosts another planet, called GJ 3929 c, a sub-Neptune orbits 3 times further than the innermost planet, at a distance of 0.081 astronomical units (12,100,000 km), [5] but still below the habitable zone. [8]