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nu Octantis is a tight binary star system comprising a primary subgiant star, nu Oct A, with about 1.6 times the mass of the Sun, and a secondary star, nu Oct B, with about half the mass of the Sun. The two stars orbit each other with a period of 1,050 days.

An additional periodic signal in the radial velocity observations (measurements of how a star moves towards or away from us) of this system was first reported by Dr David Ramm, a co-author of this new paper, during his PhD studies at the University of Canterbury, New Zealand, in 2004. This signal was consistent with the presence of a Jovian planet of about twice the mass of Jupiter orbiting around the primary star, nu Oct A, with a period of about 400 days. However, the existence of this planet has been controversial because its orbit would be so wide that it could only remain stable if it were retrograde and moved in the opposite direction to the orbit of the binary. There were no observational precedents for such a planet and strong theoretical grounds against its formation.

To settle the debate, the research team obtained new high-precision radial velocity observations using the European Southern Observatory (ESO)’s HARPS spectrograph, which confirmed the existence of the planet signal. “We performed an analysis of the new and archival radial velocity data spanning 18 years and found stable fits that require the planetary orbit to be retrograde and nearly in the same plane as the binary orbit,” said Mr Ho Wan Cheng, the first author of the paper.

Another key focus of the new study was the determination of the nature of the secondary star nu Oct B. The mass of nu Oct B suggests that it could be either a low-mass main-sequence star or a white dwarf. All stars spend most of their lives on the main sequence, generating energy through nuclear fusion of hydrogen to helium in their core. After a star has exhausted its nuclear fuel, its core collapses into a stellar remnant, which would be a white dwarf if the star’s initial mass is less than several times that of the Sun. A white dwarf has a mass comparable to that of the Sun packed in an Earth-sized volume.

To identify which type of star nu Oct B is, the research team used the adaptive optics imaging instrument SPHERE at ESO’s Very Large Telescope to observe the system. The fact that nu Oct B was not detected in these observations indicated that it must be a very faint white dwarf. This suggests that the binary system has evolved significantly since its formation, as nu Oct B has already ejected most of its mass and entered the final stage of its stellar evolution.

The research team looked into the possible primordial configurations of the binary — that is, the initial masses of the two stars and the initial orbit of the binary. “We found that the system is about 2.9 billion years old and that nu Oct B was initially about 2.4 times the mass of the Sun and evolved to a white dwarf about 2 billion years ago,” said Cheng. “Our analysis showed that the planet could not have formed around nu Oct A at the same time as the stars.”

The discovery that nu Oct B is a white dwarf opens new possibilities for how the retrograde planet may have originated. “When nu Oct B evolved into a white dwarf about 2 billion years ago, the planet could have formed in a retrograde disc of material around nu Oct A accreted from the mass ejected by nu Oct B, or it could be captured from a prograde orbit around the binary into a retrograde orbit around nu Oct A,” explained Professor Man Hoi LEE.

“We might be witnessing the first compelling case of a second-generation planet; either captured, or formed from material expelled by nu Oct B, which lost more than 75% of its primordial mass to become a white dwarf,” added Dr Trifon TRIFONOV of Zentrum für Astronomie der Universität Heidelberg in Germany and Sofia University St. Kliment Ohridski in Bulgaria and a co-author of the paper.

“The key to this exciting discovery was the use of several complementary methods to characterise the system in its entirety,” said PD Dr Sabine REFFERT of Zentrum für Astronomie der Universität Heidelberg and another co-author of the paper.

As astronomers continue to search for planets in different environments, this study highlights that planets in tight binary systems with evolved stellar components could offer unique insights into the formation and evolution of planets.

This research uses two facilities operated by the European Southern Observatory (ESO), namely the High Accuracy Radial Velocity Planet Searcher (HARPS) spectrograph at the ESO La Silla 3.6-metre telescope and the Spectro-Polarimetric High-contrast Exoplanet Research (SPHERE) instrument at the Very Large Telescope.

This new study leverages data from NASA’s Parker Solar Probe, which has become the closest spacecraft to the Sun, flying directly through the solar atmosphere. This unprecedented proximity allowed researchers to directly explore this extreme environment for the first time, providing critical data to unravel these mysteries.

The paper presents compelling evidence that the “helicity barrier” is active and profoundly alters the nature of turbulent dissipation. This effect, previously theorized, creates a barrier to the turbulent cascade of energy at small scales, fundamentally changing how fluctuations dissipate and thus how the plasma is heated.

Jack McIntyre, PhD student and the lead author of the study from Queen Mary University of London, commented: “This result is exciting because, by confirming the presence of the ‘helicity barrier’, we can account for properties of the solar wind that were previously unexplained, including that its protons are typically hotter than its electrons. By improving our understanding of turbulent dissipation, it could also have important implications for other systems in astrophysics.”

The research team also identified the specific conditions under which this barrier occurs. They found that the helicity barrier becomes fully developed when the magnetic field strength becomes large compared to the pressure in the plasma and becomes increasingly prominent when the imbalance between the oppositely propagating plasma waves that make up the turbulence is greater. Critically, these conditions are frequently met in the solar wind close to the Sun, where Parker Solar Probe is now exploring, meaning that this effect should be widespread.

Dr Christopher Chen, Reader in Space Plasma Physics at Queen Mary University of London and McIntyre’s supervisor, added: “This paper is important as it provides clear evidence for the presence of the helicity barrier, which answers some long-standing questions about coronal heating and solar wind acceleration, such as the temperature signatures seen in the solar atmosphere, and the variability of different solar wind streams. This allows us to better understand the fundamental physics of turbulent dissipation, the connection between small-scale physics and the global properties of the heliosphere, and make better predictions for space weather.”

The implications of this discovery extend beyond our own star, as many hot, diffuse astrophysical plasmas in the universe are also collisionless. Understanding how energy dissipates into heat in these environments has broad consequences for astrophysics. The direct observation of the helicity barrier in the solar wind provides a unique natural laboratory to study these complex processes.

“Saving Asha. That’s my religion. That’s my science. It’s based on love and hope and not giving up. Ever.” In Kathryn Clark’s debut, Things I Learned While I Was Dead (Faber, £8.99), we witness sisterly love taken to the extreme when Calico volunteers to be cryogenically frozen along with the dying Asha, as part of an experiment that may sound a tad dodgy, but is the only option left.

Waking up decades later, after the “Green War” has changed everything (there’s a nice nod to “Global Eco President Thunberg”), Calico discovers there’s still no cure available, and that she’s one of several teenagers in a former prison that feels like somewhere people “go to rot”.

As the thriller unfolds, there are also chapters in verse from Asha’s perspective – cryptic lines about life or death that contribute to the uneasy sense that all is not quite as it seems in this “vast but empty” space.

The book closes with an epilogue that lapses into triteness a little too often, an unnecessary coda for this thought-provoking exploration of medical ethics and the nature of grief. This is sci-fi with a big heart, demonstrating the power of speculative fiction to tackle some of life’s hardest challenges. I am excited to see what this writer does next.

Lauren Wilson’s The Goldens (Harper Fire, £8.99) tugs us into the web of a “perplexing gossamer thread of a human, every inch of her glittering gold”. Chloe, an aspiring writer unsure how to fit in at university, finds herself “bewitched” by wealthy, glamorous Clara from the instant they meet. Thrillingly, Clara seems to be drawn to her too, and that feeling of being chosen is a heady one.

“In my experience, by the age of eighteen, every girl knows another girl that she would follow to the very ends of the earth. For me, that girl was Clara Holland.”

Soon, they’re living together, and it’s all so lovely that Clara decides to invite others – reaching out to her vast army of online followers – into the circle. So begins the Goldens – “the ultimate girl gang”, a group of “strong, beautiful, independent young women” who may or may not be a little cult-like.

But people are always critical of such feminist enterprises, aren’t they – and what evidence is there, really, that Clara has anything to do with that girl who never made it home alive from one of her extravagant parties?

This appealingly glossy thriller is given depth by Chloe’s scepticism – despite her attraction to Clara, she’s also aware that the rhetoric is a little much. “When all was laid bare,” she thinks, “she was a pretty, privileged girl opening up her lovely home to girls just like her … Surely, the only young woman she was empowering in this scenario was herself?”

What Chloe gets from this isn’t just proximity to the golden girl – it’s what seems like a real career opportunity in the form of ghostwriting a book. Her complicated motivations make her plausible and relatable; this is a compelling, fun summer read.

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Mary Watson is having a busy 2025, with an adult thriller out earlier this year; her latest YA novel is Strange Nature (Bloomsbury, £9.99), in which Jasmin distracts herself from her impending Leaving Cert by falling in with a charismatic crowd of college students, hanging around on the campus she still associates with her now-disgraced professor grandfather.

His career-destroying act of violence shattered her family, but his research, we discover, remains an active influence on some sinister experiments being carried out today. (We may note here that fiction tends to over-represent the percentage of highly-dubious medical experiments; the ones that follow the rules make for far less interesting tales.)

“The Wellness Formula,” we are told, “is the blueprint for living an optimum life in the modern world. Guided by the very latest scientific advances, we take a holistic approach, one that challenges the usual assumptions around what we need to be in optimal health.”

It all sounds marvellous, but with a suspicious death on campus, it may be time to start asking some questions about research ethics. This is a delightful read for fans of dark academia and mad scientists, and it’s pleasing to see these tropes play out on an Irish canvas.

“As far as Roscoe is concerned, the accident last year never happened. I can be free of it, as easy as surrendering to the sea. I can be Iggy again, who loves to swim, and hang out, and bump into cute strangers on their paddle-boards. It hadn’t occurred to me before now, but it seems totally possible that this summer I could start again. Why didn’t I think of this sooner?”

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The space between tagline and title evaporates with Daniel Tawse’s This Book Will Make You Cry (Hodder, £9.99). I wondered initially if we were in for some metatextual fun, a tear-jerking book within a tear-jerking book, but quickly and glumly realised we are now in an era where sales and marketing teams are skipping straight to BookTok descriptions.

Despite shadowy references to an accident of the previous year, this is a fairly predictable queer summer romance – though what a joy to live in an era where there’s a sufficient volume of titles for this sentiment to even be possible.

The twist here, though clever, is one many readers will spot in advance. The emotional intensity is skilfully conveyed but the love interest himself is remarkably bland (bonding over a shared love of pizza and Pixar movies echoes Phoebe Buffay being astonished she and her birth mother agree that puppies are cute rather than ugly; this may be a return to the dark days of “insta-love”). While this book did not make me cry, it did have me rooting very much for Iggy and their emotional journey.

Finally, Becki Jayne Crossley tackles a lot in Tart (Bloomsbury, £8.99), which opens with a boy on a bike landing in a coma and then jumps to what his girlfriend, Libby, was getting up to: “I stood in front of a group of poisonous teenage girls and kissed a boy that wasn’t my boyfriend. They filmed it from at least three different angles, so I get to relive the memory I don’t fully possess every time I open a social media app.”

Libby’s ostracisation at school is brilliantly, hauntingly depicted; that very particular brand of girl-gang cruelty leaps from the page. Fortunately, there’s new girl Neha, who’s shocked no one realises Libby’s the victim here; a few small acts of kindness between the two bring them together and the sparks begin to fly.

Neha’s worried her crush on her new friend will make things weird – and anyway, isn’t Libby grieving her comatose boyfriend? Meanwhile, Libby’s never felt this way about a girl before …

We can see where it’s going, but this is sort of the point: it is a wholesome and optimistic hug of a book. Some of the more serious topics, like Neha’s grief over her dead parents, feel sidelined in favour of the fuzzy (though worthy) joy of finding your tribe, and there’s a twist that resolves the potential conflict a little too easily. One for Heartstopper fans; the gritty-realist aficionados should go elsewhere.