Astronomers find exoplanet with cloud-free atmosphere
London, May 8: Astronomers have found that a planet outside our solar system, which is similar to Saturn in mass and exceeds the size of Jupiter by 20 per cent, has an atmosphere free of clouds.
The hot gas giant, WASP-96b, periodically transits a Sun-like star 980 light years away in the southern constellation Phoenix.
Using the the European Southern Observatory's Very Large Telescope in Chile, the team studied the atmosphere of WASP-96b when the planet passed in front of its host-star.
This enabled the team to measure the decrease of starlight caused by the planet and its atmosphere, and thereby determine the planet's atmospheric composition.
"We've been looking at more than twenty exoplanet transit spectra. WASP-96b is the only exoplanet that appears to be entirely cloud-free and shows such a clear sodium signature, making the planet a benchmark for characterisation," said lead author of the study Nikolay Nikolov from University of Exeter in Britain.
Just like an individual's fingerprints are unique, atoms and molecules have a unique spectral characteristic that can be used to detect their presence in celestial objects.
The spectrum of WASP-96b shows the complete fingerprint of sodium, which can only be observed for an atmosphere free of clouds, according to the study published in the journal Nature.
It has long been predicted that sodium exists in the atmospheres of hot gas-giant exoplanets, and in a cloud-free atmosphere it would produce spectra that are similar in shape to the profile of a camping tent.
"Until now, sodium was revealed either as a very narrow peak or found to be completely missing. This is because the characteristic 'tent-shaped' profile can only be produced deep in the atmosphere of the planet and for most planet clouds appear to get in the way," Nikolov added.
Clouds and hazes are known to exist in some of the hottest and coldest solar system planets and exoplanets.
The presence or absence of clouds and their ability to block light plays an important role in the overall energy budget of planetary atmospheres.
"It is difficult to predict which of these hot atmospheres will have thick clouds. By seeing the full range of possible atmospheres, from very cloudy to nearly cloud-free like WASP-96b, we'll gain a better understanding of what these clouds are made of," explains study co-author Jonathan Fortney, Professor at University of California, Santa Cruz (UCSC), US.
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Allahabad HC orders police protection to married couple apprehending 'honour killing'
Prayagraj (PTI): The Allahabad High Court has granted protection to a married couple who expressed fear that they may be killed by the woman's family.
The order was passed by a division bench comprising Justice JJ Munir and Justice Tarun Saxena on March 25.
"No individual can make an 'honour issue' out of a consenting adult marrying a person of their own choice. It is the state's duty to protect the life, limb, and property of such persons even against their own family members," the bench said.
The court was hearing a petition filed by Prachi Agrawal and her partner, who sought relief in connection with an FIR filed under Section 87 of Bhartiya Nyaya Sanhita (BNS) for kidnapping, and abducting or inducing a woman to compel her marriage.
The couple submitted that they married at an Arya Samaj temple and possessed a marriage registration certificate issued under the Uttar Pradesh Marriage Registration Rules, 2017.
The petitioners alleged that the woman's family members were averse to their marriage and lodged a bogus FIR against them.
The couple further submitted a joint affidavit expressing apprehension of an honour killing by the woman's family.
The court said that a prima facie case was made out and issued notice to the private respondent and granted two weeks to file a counter-affidavit.
Meanwhile, as an interim measure, the court granted the petitioners protection from arrest.
The court also explicitly ordered the woman's family members and relatives not to harm the petitioners, enter their matrimonial home, or establish contact with them directly or through any electronic means.
The bench directed the Aligarh senior superintendent of police to ensure that no harm comes to the couple and posted the matter for hearing on April 8.
