WASP-76b is an ultra-hot Jupiter about 640 light-years away from Earth in the constellation Pisces. A few years ago it gained notoriety for being so hot that iron falls as rain. It’s tidally locked to its star, and the planet’s star-facing hemisphere can reach temperatures as high as 2400 Celsius, well above iron’s 1538 C melting point.
Scientists have been studying the planet since its discovery in 2013, and new evidence suggests that it’s even hotter than thought. But, almost disappointingly, there might be no iron rain after all.
In the past two and a half decades, astronomers have confirmed the existence of thousands of exoplanets. In recent years, thanks to improvements in instrumentation and methodology, the process has slowly been shifting from the process of discovery to that of characterization. In particular, astronomers are hoping to obtain spectra from exoplanet atmospheres that would indicate their chemical composition.
This is no easy task since direct imaging is very difficult, and the only other method is to conduct observations during transits. However, astronomers of the CARMENES consortium recently reported the discovery of a hot rocky super-Earth orbiting the nearby red dwarf star. While being extremely hot, this planet has retained part of its original atmosphere, which makes it uniquely suited for observations using next-generation telescopes.
Upcoming telescopes will give us more power to search for biosignatures on all the exoplanets we’ve found. Much of the biosignature conversation is centred on biogenic chemistry, such as atmospheric gases produced by simple, single-celled creatures. But what if we want to search for technological civilizations that might be out there? Could we find them by searching for their air pollution?
If a distant civilization was giving our planet a cursory glance in its own survey of alien worlds and technosignatures, they couldn’t help but notice our air pollution.
Can you picture Jupiter without any observable clouds or haze? It isn’t easy since Jupiter’s latitudinal cloud bands and its Great Red Spot are iconic visual features in our Solar System. Those features are caused by upswelling and descending gas, mostly ammonia. After Saturn’s rings, Jupiter’s cloud forms are probably the most recognizable feature in the Solar System.
Now astronomers with the Center for Astrophysics | Harvard & Smithsonian (CfA) have found a planet similar in mass to Jupiter, but with a cloud-free atmosphere.
Red dwarf stars are the most common kind of star in our neighbourhood, and probably in the Milky Way. Because of that, many of the Earth-like and potentially life-supporting exoplanets we’ve detected are in orbit around red dwarfs. The problem is that red dwarfs can exhibit intense flaring behaviour, much more energetic than our relatively placid Sun.
So what does that mean for the potential of those exoplanets to actually support life?
The ultra-powerful James Webb Space Telescope will launch soon. Once it’s deployed, and in position at the Earth-Sun Lagrange Point 2, it’ll begin work. One of its jobs is to examine the atmospheres of exoplanets and look for biosignatures. It should be simple, right? Just scan the atmosphere until you find oxygen, then close your laptop and head to the pub: Fanfare, confetti, Nobel prize.
Of course, Universe Today readers know it’s more complicated than that. Much more complicated.
In fact, the presence of oxygen is not necessarily reliable. It’s methane that can send a stronger signal indicating the presence of life.
Mars is an arid place, and aside from a tiny amount of water vapour in the atmosphere, all water exists as ice. But it wasn’t always this arid. Evidence of the planet’s past wet chapter dots the surface. Paleolakes like Jezero Crater, soon to be explored by NASA’s Perseverance Rover, provide stark evidence of Mars’ ancient past. But what happened to all that water?
It disappeared into space, of course. But when? And how quickly?
200 light years away, “super earth” exoplanet K2-141b orbits a star so closely that its “year” is only 7 hours long. Not its day…its YEAR! K2-141b orbits a mere million kilometers from the fiery surface of its star. Earth is 150 million km from our Sun. Even Mercury, the planet closest to our Sun, is never less than 47 million km. Standing on the surface of K2-141b you’d look up at an orange star that filled fifty degrees of the sky appearing a hundred times wider than our Sun appears in Earth’s sky. It would be a giant blazing orb so bright that its light shines two thirds of the way around the entire planet unlike Earth’s two day/night halves. Of course, the surface you’re standing on wouldn’t be much of a surface at all – it would be an ocean of liquid hot magma.
In September, a team of scientists reported finding phosphine in the upper atmosphere of Venus. Phosphine can be a biomarker and is here on Earth. But it’s also present on Jupiter, where it’s produced abiotically. The discovery led to conjecture about what kind of life might survive in Venus’ atmosphere, continually producing the easily-degraded phosphine.
The authors of that study were circumspect about their own results, saying that they hope someone can determine a source for the phosphine, other than life.
Now a new study says that the original phosphine detection is not statistically significant.
Does it feel like all eyes are on Venus these days? The discovery of the potential biomarker phosphine in the planet’s upper atmosphere last month garnered a lot of attention, as it should. There’s still some uncertainty around what the phosphine discovery means, though.
Now a team of researchers claims they’ve discovered the amino acid glycine in Venus’ atmosphere.