Hence astronomers were very surprised to find that this method yielded a mass of 0. Now our theory of stellar evolution seemed to be clashing with our theory of stellar atmospheres as well.
The authors were very surprised to find out that the orbit of 40 Eridani B had not been updated with new observations over the more than four decades since the work of Heintz. They contacted the binary star group at the United States Naval Observatory USNO , which in turn assembled all the data they could find containing this star.
With these new measurements, the group found a smaller orbital period, which led them to obtain a much higher mass for 40 Eridani B than Heintz: 0. This new mass agrees within uncertainties with the value derived by Giammichele and collaborators. To double check, the authors also fitted all the available spectra of 40 Eridani B to obtain the average gravity and, using radius derived from parallax measurements, calculated a new mass. They found a mass of 0. We can thus rest assured that our spectral analysis method for deriving masses indeed works!
The mystery of the heavier mass is solved. Finally, the authors compared the new independent estimates of mass and radius to theoretical mass-radius relationships. As you can see in Fig. As the mass was revised above the limit for single-star evolution, we would expect 40 Eridani B to be a carbon-oxygen core white dwarf. Those two elements are the heaviest mosts stars can synthesise, so they form the core of most white dwarfs we know.
This indeed turns out to be the case for 40 Eridani B. The only catch is that the authors have to assume a thin hydrogen atmosphere, while our modern theories of stellar evolution mostly predict white dwarfs to have thick hydrogen layers. Figure 1: The position of 40 Eridani B in a mass-radius plane given the new derived values for mass and radius is marked by the blue circle.
The orange line shows the mass-radius relationship for an iron core, which was needed to explain previous estimates of mass and radius, but is very far from the new ones. The blue lines show the relationship assuming a carbon-oxygen core. The habitable zone of Vulcan is closer to its dwarf star than the Earth's is to the sun because 40 Eridani A is cooler and dimmer than Sun. NASA scientists create a scale for evaluating possible signs of life beyond Earth. A survey of strange exoplanets called 'hot Jupiters,' a legacy of the retired Spitzer Space Telescope, reveals some secrets — and a few surprises.
Exoplanet Travel Bureau. This set of travel posters envision a day when the creativity of scientists and engineers will allow us to do things we can only dream of now. Epsilon Eridani does have one planet - an uninhabitable gas giant.
Now astronomers on the University of Florida-led Dharma Planet Survey have found something that seems a bit more habitable orbiting 40 Eridani A. More precisely, it's an object known as a super-Earth - a rocky planet around twice the size of Earth, orbiting 40 Eridani A just inside the system's habitable zone - not too hot and not too cold. The innermost planet was a rocky class B planet named Ket-Cheleb. The icy planetoid Delta Vega was located in the outer asteroid belt.
This system was threatened by the Dominion after they occupied Benzar in In , 40 Eridani A was confirmed to have at least one planet orbiting it, albeit a " super-Earth " orbiting too close to the star to support life. Memory Alpha Explore. Christopher Pike Number One. James T. USS Protostar.
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