Posted on 01/30/2025 12:58:45 PM PST by Red Badger
One of these exoplanets, HD 20794d, is likely to be a rocky planet in the habitable zone of its parent star, the G-dwarf HD 20794.
This image shows the habitable zone around HD 20794 (green) and the trajectory of the three planets in the system. Image credit: Gabriel Pérez Díaz / SMM / IAC.
“HD 20794, around which HD 20794d orbits, is not an ordinary star,” said UNIGE astronomer Xavier Dumusque.
“Its luminosity and proximity makes it an ideal candidate for future telescopes whose mission will be to observe the atmospheres of exoplanets directly.”
HD 20794 is a bright G6V star located 6.04 parsecs (19.7 light-years) away in the constellation of Eridanus.
Also known as LHS 19 or e Eri, the star hosts at least three massive exoplanets: HD 20794b, c, and d.
They have orbital periods of 18.3, 89.7, and 647.6 days, along with masses of 2.2, 3, and 5.8 Earth masses, respectively.
“The interest in the super-Earth planet HD 20794d lies in its position in the habitable zone of its star, the zone that delimits the place where liquid water can exist, one of the conditions necessary for the development of life as we know it,” Dr. Dumusque and colleagues said.
“Instead of following a relatively circular orbit, like the Earth or Mars, HD 20794d follows an elliptical trajectory with large changes in the distance to its star during its revolution.”
“The planet thus oscillates between the inner edge of its star habitable zone (0.75 AU) and outside of it (2 AU) along its orbit.”
“If there is water on HD 20794d, it would pass from the state of ice to the liquid state, conducive to the appearance of life, during the planet’s revolution around the star.”
The astronomers monitored the HD 20794 system with the Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations (ESPRESSO) instrument, which is installed at ESO’s Very Large Telescope (VLT) in Paranal, Chile.
They joined ESPRESSO data with the data from the High Accuracy Radial velocity Planet Searcher (HARPS) instrument, which is installed at the 3.6-m telescope in La Silla, Chile, including archival data and new measurements from a recent program.
“The HD 20794 system is a high-priority target for future atmospheric characterization with direct imaging facilities,” the researchers said.
Their paper was published in the journal Astronomy & Astrophysics.
_____
N. Nari et al. 2025.
Revisiting the multi-planetary system of the nearby star HD 20794. Confirmation of a low-mass planet in the habitable zone of a nearby G-dwarf. A&A 693, A297;
doi: 10.1051/0004-6361/202451769
HOT freeze HOT freeze ........
Here we go.
· join · view topics · view or post blog · bookmark ·
· post new topic · subscribe ·Google news searches: exoplanet · exosolar · extrasolar ·
Hmmm..
Maybe that’s why some of us feel as though someone or something is spying on us?
How exactly does one pronounce “Eridanus”?
Eri - dan- us.............
“How exactly does one pronounce “Eridanus”?”
Rhymes with “Uranus”.
Arid anus. The most puckered of stars.
Life is tough enough without these space nuts adding to it. Try it in a sentence:
"Our new moisturizing creme can help you deal with your Eridanus"
And monkeys ‘are likely’ to jump outta my butt!
I like the graphic. just imagine getting to see such a system.
I like how astronomers are addicted to espresso. That’s good when you have to stay up all night.
All orbits are elliptical.
Gravity on all those planets would be a bitch.
We could adopt the Greek spelling: Eridanos, with the accept on the last syllable.
… But some orbits are more elliptical than others.
Of course
A number of rivers have the -dan- element in them, besides Eridanos: Danube (Danuvius), Rhodanus (the Rhone). River names are often taken over by new populations so these could go back to a very early time.
The Jordan River (Iordanes in Greek) looks similar but may not belong with the other examples (Hebrew yarden).
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.
