lpetrich
Contributor
The Transiting Exoplanet Survey Satellite is finding planets.
NASA_TESS (@NASA_TESS) | Twitter -- announcements of TESS's first two candidate exoplanets.
The first one orbits
Pi Mensae, a very Sunlike star some 60 light-years / 18 parsecs away, a star already known to have a planet.
[1809.05967] TESS Discovery of a Transiting Super-Earth in the $\Pi$ Mensae System
[1809.07573] TESS's first planet: a super-Earth transiting the naked-eye star $\pi$ Mensae
Pi Mensae is already known to have a super-Jovian planet, a planet with at least 10 Jupiter masses, though likely Jupiter-sized. It orbits with a period of 5.89 (Earth years), and has a mean distance of 3.4 AU and an eccentricity of 0.64, giving a distance range of 1.2 to 5.5 AU.
This most recent planet was confirmed by radial-velocity measurements, and it has a distance of 0.068 AU, a period of 6.27 (Earth) days, a mass of 4.8 Earth masses and a radius of 2.1 Earth radii. Its average density is nearly 3 g/cm^3, about what one would expect from an all-water planet with its mass. Since that planet likely has rock and iron in it, it would thus have to have a thick layer of hydrogen and helium, much as Uranus and Neptune do.
This planet's equilibrium surface temperature is around 1100 C, hot enough to glow in visible light.
The second one orbits red dwarf LHS 3844 about 50 light years / 15 parsecs away.
[1809.07242] TESS Discovery of an ultra-short-period planet around the nearby M dwarf LHS 3844
The planet has radius 1.32 Earth radii and it orbits its star once every 11 hours. It orbits at distance 0.0062 AU and it has an equilibrium temperature of 800 K.
The planet thus orbits at 1.3 solar radii, while its star's radius is 0.19 solar radii. So that star would be about 17 degrees of arc in the sky.
NASA_TESS (@NASA_TESS) | Twitter -- announcements of TESS's first two candidate exoplanets.
The first one orbits
Pi Mensae, a very Sunlike star some 60 light-years / 18 parsecs away, a star already known to have a planet.[1809.05967] TESS Discovery of a Transiting Super-Earth in the $\Pi$ Mensae System
[1809.07573] TESS's first planet: a super-Earth transiting the naked-eye star $\pi$ Mensae
Pi Mensae is already known to have a super-Jovian planet, a planet with at least 10 Jupiter masses, though likely Jupiter-sized. It orbits with a period of 5.89 (Earth years), and has a mean distance of 3.4 AU and an eccentricity of 0.64, giving a distance range of 1.2 to 5.5 AU.
This most recent planet was confirmed by radial-velocity measurements, and it has a distance of 0.068 AU, a period of 6.27 (Earth) days, a mass of 4.8 Earth masses and a radius of 2.1 Earth radii. Its average density is nearly 3 g/cm^3, about what one would expect from an all-water planet with its mass. Since that planet likely has rock and iron in it, it would thus have to have a thick layer of hydrogen and helium, much as Uranus and Neptune do.
This planet's equilibrium surface temperature is around 1100 C, hot enough to glow in visible light.
The second one orbits red dwarf LHS 3844 about 50 light years / 15 parsecs away.
[1809.07242] TESS Discovery of an ultra-short-period planet around the nearby M dwarf LHS 3844
The planet has radius 1.32 Earth radii and it orbits its star once every 11 hours. It orbits at distance 0.0062 AU and it has an equilibrium temperature of 800 K.
The planet thus orbits at 1.3 solar radii, while its star's radius is 0.19 solar radii. So that star would be about 17 degrees of arc in the sky.