Radial velocity signal from exoplanet candidate orbiting HD 26965 (40 Eridanus A) — host Spock's fictional home planet Balkanin Star Trek A new study suggests that the universe is powered by stellar activity.
26965 High Resolution It is a bright K-type dwarf star located 16 light years away in the constellation Eridanus.
Also known as 40 Eridani A, the star is a member of the triple star system 40 Eridani.
It is about 6.9 billion years old, its mass is about 78% of the Sun, and its radius is 87% of the Sun.
In 2018, astronomers announced they may have discovered a super-Earth exoplanet that orbits HD 26965 every 42 days.
But scientists warned that it could be a nasty stellar vibration disguised as a planet.
“As we continue to search for unknown new worlds, two methods for discovering exoplanets stand out above the rest,” said Dartmouth College astronomer Abigail Burrows and her colleagues.
“The transit method, which involves observing the slight dimming of a star's light as a planet passes across its face, accounts for the majority of detections.”
“But the radial velocity method has also been very successful in discovering exoplanets. This method is especially important for planetary systems that don't cross the face of their star as seen from Earth.”
“By tracking subtle changes in the star's light, scientists can measure the wobble of the star itself as the gravity of an orbiting planet tugs it in one direction and then another.”
“For very large planets, the radial velocity signal almost always allows for unambiguous planet detection. But for less massive planets, there can be problems.”
In the new study, astronomers NeedA radial velocity meter mounted on the 3.5m WIYN telescope at Kitt Peak National Observatory.
“NEID, like other radial velocity meters, makes use of the Doppler effect, which reveals a star's wobbling motion through changes in its light spectrum,” the researchers explained.
“In this case, analysing the supposed planet's signal in different wavelengths of light emitted from different levels of the stellar envelope, or photosphere, revealed significant differences between the measurements of the individual wavelengths (Doppler shifts) and the overall signal obtained by combining them all together.”
“So the planet's signal is probably just a flickering of something on the star's surface that coincides with its 42-day rotation. It's probably a combination of a swirling of hot and cold layers below the star's surface, called convection, and stellar surface features such as bright, active regions like spots or plages, either of which could alter the star's radial velocity signal.”
“While this new discovery eliminates the possibility of 40 Eridanus A being the planet Vulcan, at least for now, the news isn't all bad.”
“The demonstration of such finely calibrated radial velocity measurements has the potential to provide much clearer observations of wobble and vibrations on the surfaces of real planets and distant stars.”
of study Published in Astronomical Journal.
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Abigail Burrows othersIn 2024, NEID revealed that the planet candidate orbiting HD 26965 is stellar active. AJ 167, 243; doi: 10.3847/1538-3881/ad34d5
Source: www.sci.news
