Exoplanet

Life in a hydrogen-rich atmosphere Astrophysics

Life in a hydrogen-rich atmosphere

The exoplanet K2-18b, about 124 light-years from Earth, is a kind of mini-Neptune, as astronomers discovered this past year. It is seven to ten times heavier than Earth and its radius is 2.7 times larger. K2-18b orbits its host star, a red dwarf, once every 33 days. Thus, it is located in its star’s habitable zone. For astronomers, however, it has one other special noteworthy feature: hydrogen, helium, and water vapor have been detected in its atmosphere. In the media, K2-18b has even been described as “Earth 2.0,” which it very definitively is not. The researchers who studied it…
Blown to dust: the first exoplanet visible in a telescope is no more Astrophysics

Blown to dust: the first exoplanet visible in a telescope is no more

In 2008, researchers looking at images from the Hubble Space Telescope found a bright spot moving around the star Fomalhaut located 25 light-years from Earth. At 400 million years old, Fomalhaut is still relatively young. The star, twice as heavy as the Sun and 17 times brighter, is also circled by a dust disk that the researchers identified as a remnant from planetary formation. Fomalhaut b was thus the first exoplanet detected through direct, optical imaging, not just indirectly through star crossings or wobbling patterns of movements by its star. In 2015, the approximately Jupiter-sized planet was even given…
Kepler-1649c: an Earth twin with a short-tempered host star Astrophysics

Kepler-1649c: an Earth twin with a short-tempered host star

The Kepler telescope has already been shut down, but astronomers are still finding new exoplanets in its data. Kepler-1649c, which is 300 light-years from Earth, is one of these recently discovered treasures. The planet was overlooked by the first, automated search through the data. The rocky planet has one very intriguing characteristic: it is the most Earth-like exoplanet discovered to date. Kepler-1649c is only 1.06 times larger than Earth. Its host star supplies it with about three-quarters of the energy that the Earth receives from the Sun. That means that water, if it exists there, would be liquid on…
Today’s forecast: cloudy with a 100% chance of iron rain in the evening Space

Today’s forecast: cloudy with a 100% chance of iron rain in the evening

The exoplanet, WASP-76b, about 640 light-years from Earth, orbits its host star, WASP-76, once every approximately 1.8 days at the relatively small distance of only 0.03 astronomical units (AU). The Earth, in contrast, is at a distance of 1 AU from the Sun. The star, WASP-76, is somewhat larger and hotter than the Sun, but that doesn’t make much of a difference for the planet orbiting around it. At such a small distance, the planet would be damn hot no matter how big the star was. The planet, almost as massive as our Jupiter, is therefore classified as a…
Hot and cold: an ice giant orbiting a white dwarf Astrophysics

Hot and cold: an ice giant orbiting a white dwarf

In a few billion years, when our Sun has exhausted its supply of fuel, it will first turn into a red giant and then collapse to form a white dwarf. Some planets of our Solar System will probably survive this time (if they’re not flung out into deep space). Astronomers know this will happen – theoretically. But until now, nobody had ever found a white dwarf with a planet in orbit around it. So, it’s understandable why researchers are so excited about the discovery of WDJ0914+1914, which is located in the constellation Cancer about 1500 light-years away. “It was one…
How exoplanets develop in multiple-star systems Astrophysics

How exoplanets develop in multiple-star systems

In the novel, “The Three-Body Problem,” a civilization that developed in a system with three stars plays an important role. This situation has dramatic consequences for the civilization’s planet, which I don’t want to spoil for you. I was reminded of the novel when I read a press release of research work at the University of Jena. Dr. Markus Mugrauer, an astrophysicist there, examined 1300 known star systems with exoplanets to determine how many stars there were within these systems. To do this, he used the most up-to-date version of the data from the ESA Gaia Mission. A clever approach…
Could an Earth-like planet also survive in an eccentric solar system? Life

Could an Earth-like planet also survive in an eccentric solar system?

HR5183 is a yellow dwarf star, not very different from our own Sun and located about 103 light-years from Earth. After more than 20 years of observation, astronomers finally found a planet, of about three times Jupiter’s mass, orbiting the star this past summer. Why did it take so long? The planet, HR5183 b, needs 75 years to complete one orbit around its star. Therefore, the period at which it affects the light curve of its star is also correspondingly long. But what surprised the astronomers even more was the planet’s unusual orbit. HR5183 b comes about as close…
A planet that shouldn’t exist Space

A planet that shouldn’t exist

GJ 3512 is a red dwarf. The star is about 31 light-years from us and has only 12% the mass of the Sun. But as far as the size of its companions go, GJ 3512 doesn’t hold back. As a German and Spanish research team has discovered, it has a gas giant with a mass of almost half our Jupiter. “Such stars should actually only have Earth-sized planets or at most super-Earths with slightly more mass,” says Professor Christoph Mordasini of the Physics Institute at the University of Bern, discussing plausible scenarios for the formation of the large exoplanet…