One-third of the planets orbiting the most common stars across the Milky Way galaxy may hold onto liquid water and possibly harbour life, according to a study based on latest telescope data.
The most common stars in our galaxy are considerably smaller and cooler, sporting just half the mass of the Sun at most. Billions of planets orbit these common dwarf stars.
The analysis, published in the journal Proceedings of the National Academy of Sciences, shows that two-thirds of the planets around these ubiquitous small stars could be roasted by tidal extremes, sterilising them.
However, that leaves one-third of the planets—hundreds of millions across the galaxy—that could be in a goldilocks orbit close enough, and gentle enough, to be possibly habitable.
“I think this result is really important for the next decade of exoplanet research, because eyes are shifting towards this population of stars,” said Sheila Sagear, a doctoral student at the University of Florida (UF) in the US.
“These stars are excellent targets to look for small planets in an orbit where it’s conceivable that water might be liquid and therefore the planet might be habitable,” Sagear said in a statement.
Sagear and UF astronomy professor Sarah Ballard measured the eccentricity of a sample of more than 150 planets around M dwarf stars, which are about the size of Jupiter.
The more oval shaped an orbit, the more eccentric it is. If a planet orbits close enough to its star, at about the distance that Mercury orbits the Sun, an eccentric orbit can subject it to a process known as tidal heating.
As the planet is stretched and deformed by changing gravitational forces on its irregular orbit, friction heats it up. At the extreme end, this could bake the planet, removing all chance for liquid water.
“It’s only for these small stars that the zone of habitability is close enough for these tidal forces to be relevant,” Ballard said.
The researchers used data from NASA’s Kepler telescope, which captures information about exoplanets as they move in front of their host stars.
To measure the planets’ orbits, they focused especially on how long the planets took to move across the face of the stars. Their study also relied on new data from the Gaia telescope, which has measured the distance to billions of stars in the galaxy.
“The distance is really the key piece of information we were missing before that allows us to do this analysis now,” Sagear said.
The team found that stars with multiple planets were the most likely to have the kind of circular orbits that allow them to retain liquid water.
Stars with only one planet were the most likely to see tidal extremes that would sterilise the surface, according to the researchers.
Since one-third of the planets in this small sample had gentle enough orbits to potentially host liquid water, that likely means that the Milky Way has hundreds of millions of promising targets to probe for signs of life outside our solar system, they added.
Aditya L1 Solar Mission Begins Studying Energetic Particles in Solar Wind
After India’s solar mission, Aditya L1 began its journey towards Lagrange point 1 following a key manoeuvre, it has started studying energetic particles in the solar wind from space and will continue to do so for the rest of its life, a senior astrophysicist said. The study of the solar wind, the continuous flow of charged particles from the sun which permeates the solar system, will be carried out with the help of a device named Supra Thermal & Energetic Particle Spectrometer (STEPS), a part of the Aditya Solar wind Particle Experiment (ASPEX) payload.
“STEPS is now working from space. However, it was not sitting idle earlier. It has started functioning from within the magnetic field of the Earth since September 10 when Aditya was 52,000 kilometres above our planet,” Dr Dibyendu Chakrabarty, professor of Space and Atmospheric Sciences at the Physical Research Laboratory (PRL) said.
STEPS was developed by the PRL with support from the Space Application Centre (SAC) in Ahmedabad.
“During the travel time of four months (till Aditya L1 reaches its destination), it will study energetic particles in the solar wind. The data will help maintain the health and performance of our space assets in a better way,” Dr Chakrabarty told PTI.
The key aim of STEPS is to study the environment of energetic particles from the spacecraft’s position on the L1 point till it will function, he said. “The data from STEPS in the long term will also help us understand how space weather changes,” the space scientist said.
STEPS comprises six sensors, each observing in different directions and measuring supra-thermal and energetic ions. The data collected during the Earth’s orbits helps scientists to analyse the behaviour of particles surrounding the planet, especially in the presence of its magnetic field.
Aditya-L1, launched by the Indian Space Research Organisation (ISRO) on September 2, will go up to the First Lagrangian point, about 1.5 million km from the Earth ISRO on September 18 said on X: “Off to Sun-Earth L1 point! The Trans-Lagrangean Point 1 Insertion (TL1I) manoeuvre is performed successfully. The spacecraft is now on a trajectory that will take it to the Sun-Earth L1 point.” Lagrangian points are where gravitational forces, acting between two objects, balance each other in such a way that the spacecraft can ‘hover’ for a longer period of time.
The L1 point is considered the most significant of the Lagrangian points, for solar observations, which were discovered by mathematician Joseph Louis Lagrange.
Elon Musk’s Neuralink Receives Approval to Start Brain Implant Human Trial
Billionaire entrepreneur Elon Musk‘s brain-chip startup Neuralink said on Tuesday it has received approval from an independent review board to begin recruitment for the first human trial of its brain implant for paralysis patients.
Those with paralysis due to cervical spinal cord injury or amyotrophic lateral sclerosis may qualify for the study, it said but did not reveal how many participants would be enrolled in the trial, which will take about six years to complete.
The study will use a robot to surgically place a brain-computer interface (BCI) implant in a region of the brain that controls the intention to move, Neuralink said, adding that its initial goal is to enable people to control a computer cursor or keyboard using their thoughts alone.
The company, which had earlier hoped to receive approval to implant its device in 10 patients, was negotiating a lower number of patients with the US Food and Drug Administration (FDA) after the agency raised safety concerns, according to current and former employees. It is not known how many patients the FDA ultimately approved.
Musk has grand ambitions for Neuralink, saying it would facilitate speedy surgical insertions of its chip devices to treat conditions like obesity, autism, depression and schizophrenia.
In May, the company said it had received clearance from the FDA for its first-in-human clinical trial when it was already under federal scrutiny for its handling of animal testing.
Even if the BCI device proves to be safe for human use, it would still potentially take more than a decade for the startup to secure commercial use clearance for it, according to experts.
© Thomson Reuters 2023
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)
ISRO’s Aditya-L1 Performs TL1I Manoeuvre, Set to Reach Sun-Earth L1 Point
The Indian Space Research Organisation (ISRO) announced on Tuesday that its maiden solar mission — Aditya-L1 — has performed the Trans-Lagrangean Point 1 Insertion (TL1I) manoeuvre successfully and the spacecraft was now in a trajectory that will take it to the Sun-Earth L1 point. ISRO also informed that it marked the fifth consecutive time that the ISRO had successfully transferred an object on a trajectory toward another celestial body or location in space.
A post on the ISRO official handle on social media platform X read, “Aditya-L1 Mission | Off to Sun-Earth L1 point | The Trans-Lagrangean Point 1 Insertion (TL1I) manoeuvre is performed successfully. The spacecraft is now on a trajectory that will take it to the Sun-Earth L1 point. It will be injected into an orbit around L1 through a manoeuvre after about 110 days. This is the fifth consecutive time ISRO has successfully transferred an object on a trajectory toward another celestial body or location in space.”
Earlier, a launcher carrying the Aditya-L1 spacecraft blasted off from the Satish Dhawan Space Station at Sriharikota in Andhra Pradesh. The primary objectives of India’s maiden solar mission include collecting scientific data and marking another milestone in India’s solar exploration efforts.
The agency had earlier posted on X, “Aditya-L1 Mission: Aditya-L1 has commenced collecting scientific data. The sensors of the STEPS instrument have begun measuring supra-thermal and energetic ions and electrons at distances greater than 50,000 km from Earth. This data helps scientists analyze the behaviour of particles surrounding Earth. The figure displays variations in the energetic particle environment, collected by one of the units.”
The Supra Thermal and Energetic Particle Spectrometer (STEPS) instrument, a part of the Aditya Solar Wind Particle Experiment (ASPEX) payload, also started its data-gathering operations earlier.
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