In the suburbs of the Sun, the star Vega baffles astrophysicists. One of the first detected with a planetary disk of debris, which appears not to be surrounded by any planetary procession, even when combining the observational powers of the Hubble and James-Webb telescopes. This is a unique case that planetologists dealing with cosmogony do not yet understand.
Vega is the fifth brightest star in the sky and the brightest star in the constellation Lyra. It is only about 25 light years from the Solar System and has a mass more than twice that of the SunSun, which means, according to the well-tested theory of stellar structure and evolution, that it will only remain on the main sequence for a billion years before becoming a red giant, then ending its life as a white dwarf. Currently, it must be around 450 million years old.
Because of its proximity, it was therefore a target of choice for astrophysicistsastrophysicists and in the early 1980s, during the Iras mission observing in the infraredinfrared from space, a disc of mattermatter was detected around it, similar to the one which, currently in the Solar System, is responsible for the zodiacal light.
Hubble was of course subsequently mobilized to observe it and more recently, the James-Webb space telescope, the JWST.
Simulations of the formation of planetary systems can be compared to the results of observations of this process by the James Webb Space Telescope. To obtain a fairly accurate French translation, click on the white rectangle at the bottom right. English subtitles should then appear. Then click on the nut to the right of the rectangle, then on “Subtitles” and finally on “Automatically translate”. Choose “French”. © NASA Goddard
A debris disk after gas dissipation from a protoplanetary disk
Vega has long no longer been in a phase with a protoplanetary diskprotoplanetary disk where planets are forming, but we can think that, just as in the case of the Solar System, its debris disk, a vestige of this protoplanetary disk and now devoid of the gas gas that it contained, is formed of dust produced by the continuous collisions between the asteroidsasteroids in orbitorbit and the debris of the cometscomets in evaporation, dust which eventually falls towards the central star.
But here too, as in the case of the Solar System, we observe in the debris disks around stars older than a hundred million years low density intervals dug by the planets in orbit accreting this dust. Thus, as explained in a press release from NasaNasa, Fomalhaut, which is approximately the same distance, at the same age and at the same temperature as Vega, has three interlocking debris belts.
What are the differences between Vega and other stars?
Just like the “shepherd satellites” of Saturn which gravitationally confine the dust of its rings, we have every reason to think that those of the Fomalhaut debris disk also undergo the same phenomenon due to the existence of exoplanetsexoplanets although none have been positively identified to date. Which makes George Rieke, also a member of the University of Arizona research team, wonder: “ Given the similarity between the stars of Vega and Fomalhaut’s stars, why does Fomalhaut appear to have been able to form planets and not Vega? ».
Schuyler Wolff is not to be outdone: “ What’s the difference? Is it the circumstellar environment, or the star itself, which created this difference? What is intriguing is that the same physicsphysics is at work in both cases ».
« Hubble and Webb’s observations provide so much detail that they tell us something completely new about the Vega system that no one knew before », adds Rieke while his colleague AndrasAndras Gáspár declares, for his part, that “ between the Hubble and Webb telescopes, we have a very clear view of Vega. It’s a mysterious system because it’s different from other circumstellar disks we’ve observed. Vega’s disc is smooth, ridiculously smooth ».
The formation of the Solar System explained by Sean Raymond, astrophysicist at the Bordeaux Astrophysics Laboratory. A video of the AstrobioEducation educational course. © French Society of Exobiology
Did you know?
L’Infrared Astronomical Satellite (Iras) was the first space telescope to study the entire sky in infrared light. It was placed by NASA in a sun-synchronous orbit on January 25, 1983, operating for ten months until the liquid helium used to cool its instruments ran out. Iras was a technical and scientific precursor to future iconic infrared space missions, including the Spitzer, James-Webb, and Herschel space telescopes. Iras detected around 350,000 infrared sources and made a number of unexpected discoveries, including evidence of dust grains around the stars Vega and Beta Pictoris, which already strongly suggested the existence of planetary systems around other stars.
So, in the case of Vega, a puzzling excess of infrared light from hot dust was detected by Iras. It was interpreted as a shell or disk of dust extending twice Pluto’s orbital radius from the star, providing the first evidence of the existence of material orbiting a star.
Scientists began seriously modeling the formation of protoplanetary disks and planets after World War II. On this subject, we can cite the work during the 1950s and 1960s of pioneers such as Viktor SafronovAlastair Cameron and Harold Urey, inspired by a hypothesis that was first put forward by Immanuel Kant in 1775. Advances in computers have made it possible to explore models proposed since then in more detail.
Vega: The Star That Thinks It’s Special
Well, if you thought your life was confusing, welcome to the cosmic conundrum that is Vega! It’s the fifth brightest star in the night sky and, might I add, *the* brightest star in the constellation Lyra. And guess what? It’s just a casual 25 light years away. Not to brag, but with a mass more than twice that of our Sun, Vega thinks it can outshine the solar system. I mean, honestly, who does this star think it is? A celebrity?
As we’ve learned from the keen scientific minds, Vega baffles astrophysicists—yes, actual minds with fancy degrees in astrophysics! They’ve pointed the world’s top telescopes, like the Hubble and James Webb, but still, nothing! It’s as if Vega is holding onto its secrets tighter than your grandma holds onto her cookie recipe. They’ve detected a disk of debris around Vega, but it seems to be doing a very good job of not forming any planets. Perhaps it just wants to be single for a while; I get that!
The Sizzling Planets and Smooth Disks
Imagine a star with the whole cosmic vibe of a young adult who just moved into a new apartment and decided to feng shui their space. Picked up all the nice furniture, yet mysteriously has no roommates—just a debris disk. Now that’s the whole *protoplanetary disk* phase that Vega seems to have skipped, like it’s been reading the Horoscopes and decided, “Nah, I’m not ready for that.”
Instead of lively bodies aligning in welcoming orbits, we’re treated to vast, empty space around Vega. Not a planet in sight! And oh, the irony! In other systems like Fomalhaut, which, by the way, is living it up with *three* debris belts, Vega’s existence feels, well, a bit lonely. I mean, what’s the secret? *Did Vega just ghost the planet formation plan*? Or is it just bad at meeting new planetary friends?
Astrophysicists in Agony
Why, oh why, does Vega refuse to play the cosmic game? That’s what our confused astrologers of the material universe, Rieke and Wolff, are trying to figure out! Is it the star itself? Or perhaps Vega just doesn’t vibe well with its surrounding material. We could go further and say, “Maybe Vega just doesn’t believe in love at first sight?” I mean, with that *ridiculously smooth* disk—it’s like its dating profile is just a picture of its facial features, with no real detail about personality.
Hubble and Webb promise to dish the dirt on Vega like cosmic gossip columnists, revealing how Vega’s angelic demeanor isn’t all that glamorous. Everyone’s trying to get to the bottom of how and why Vega is so, well, *different*. And trust me, when it comes to astrophysics, “different” is not awkward—it’s a mystery that keeps everyone awake at night, contemplating over their cups of coffee.
Vega: An Evolutionary Outlier
It’s a stellar soap opera out there, where Vega, the drama queen, throws out curveballs that keep astrophysicists guessing about its past. You’ve got the Infrared Astronomical Satellite (IRAS) paving the way for this epic saga back in the 80s, revealing a shell or disk of dust around Vega. Think of it as Vega’s protective bubble, serving to hide its perceived shortcomings from its fellow stars. Talk about a star with a flair for the dramatic!
But amidst this cosmic masquerade ball, Vega holds its ground, defying our expectations and leading us to rethink how planetary systems form. It’s like that one friend in your group who goes against the grain and keeps everyone on their toes. Vega just might be the key to understanding why some stars form families and others—well, seem like they’re eternally swiping left at the cosmic dating game.
So here we stand, astronomical adventurers, peering into the cosmic mystery of Vega, wondering if it’s time to shed its singleness and make some planets—or if it’ll content itself with being the star of its own one-star show for time immemorial. Only the universe knows!
In the vicinity of the Sun, the star Vega continues to perplex astrophysicists with its enigmatic characteristics. Vega was among the first stars detected with a planetary debris disk surrounding it; however, it notably lacks any clear planetary formations. Despite utilizing the advanced observational capabilities of both the Hubble and James Webb Space Telescopes, the nature of this phenomenon remains elusive, presenting a unique challenge for planetologists engaged in the field of cosmogony.
As the fifth brightest star visible in the sky and the most luminous star in the constellation of Lyra, Vega is situated a mere 25 light-years from our Solar System. With a mass surpassing twice that of our Sun, it is predicted that Vega’s main sequence lifetime will be limited to about one billion years, after which it will evolve into a red giant and ultimately conclude its life as a white dwarf. Currently estimated to be around 450 million years old, it is on a trajectory toward this evolutionary path.
Due to its relative proximity, Vega has long been a focal point for astrophysical studies. In the early 1980s, the Infrared Astronomical Satellite (IRAS) mission made a groundbreaking discovery, detecting a disc of matter surrounding Vega. This disc bears similarities to the zodiacal light phenomenon observed in our own Solar System, offering intriguing parallels between kinematic structures in different stellar environments.
The observational power of Hubble was quickly enlisted to further investigate Vega. More recently, the James Webb Space Telescope (JWST) has taken over to enhance our comprehension of its complexities and the nature of its debris disk.
Simulations aimed at understanding the formation processes of planetary systems can now be directly compared with observational data collected by the James Webb Space Telescope.
A debris disk after gas dissipation from a protoplanetary disk
Vega has transitioned beyond the protoplanetary disk phase necessary for planet formation. Its current debris disk is a remnant of that earlier stage, now stripped of the gaseous components which once filled it. This disk primarily consists of dust created through the constant collisions of orbiting asteroids and the remnants of evaporating comets—a process by which particles gradually spiral inward towards the central star.
Yet, intriguingly, even with older stars like Vega displaying debris disks, the patterns observed differ significantly. For instance, NASA has indicated that Fomalhaut, which shares similar distance, age, and temperature characteristics with Vega, possesses three distinct interlocking debris belts—an observation suggesting a more complex dynamic at work in systems that have managed to form planets.
What are the differences between Vega and other stars?
Akin to the “shepherd satellites” of Saturn that maintain the dust within its rings, there’s a hypothesis that Fomalhaut’s debris disk is also influenced by the gravitational presence of exoplanets, although none have yet been conclusively identified to this date. This provokes curiosity from researchers like George Rieke, who reflects, “ Given the similarity between the stars of Vega and Fomalhaut’s stars, why does Fomalhaut appear to have been able to form planets and not Vega? ”
Schuyler Wolff echoes this sentiment, questioning: “ What’s the difference? Is it the circumstellar environment or the star itself that creates this disparity? What is intriguing is that the same physics applies in both scenarios ”.
According to Rieke, “ Hubble and Webb’s observations provide such detailed insights that they reveal entirely new information about the Vega system previously unknown to scientists ”. His colleague Andras Gáspár adds that “ the combination of Hubble and Webb instruments allows us an exceptional view of Vega. It’s a puzzling system, as it deviates markedly from the other circumstellar disks we’ve studied. Vega’s disk exhibits a smoothness that is almost absurd ”.
L’Infrared Astronomical Satellite (Iras) was the first space telescope to study the entire sky in infrared light. It was placed by NASA in a sun-synchronous orbit on January 25, 1983, operating for ten months until the liquid helium used to cool its instruments ran out. Iras was a technical and scientific precursor to future iconic infrared space missions, including the Spitzer, James-Webb, and Herschel space telescopes. Iras detected around 350,000 infrared sources and made a number of unexpected discoveries, including evidence of dust grains around the stars Vega and Beta Pictoris, which already strongly suggested the existence of planetary systems around other stars.
In the case of Vega, a puzzling excess of infrared light from hot dust was detected by Iras. It was interpreted as a shell or disk of dust extending twice Pluto’s orbital radius from the star, providing the first evidence of the existence of material orbiting a star.
Serious modeling of protoplanetary disk formation and planetary evolution began in earnest after World War II, led by pioneering scientists in the 1950s and 1960s. These efforts, inspired by an earlier hypothesis proposed by Immanuel Kant in 1775, have since been refined by advancements in computational technology, allowing for deeper explorations of the proposed models.
Ubstantial insights into the enigmatic difference between Vega and similar stars like Fomalhaut. Our data suggests that the environment surrounding Vega might not be conducive to planet formation, which could be a key factor in understanding why it has not been able to form planets despite its favorable conditions.”
Exploring the Mystery of Vega’s Debris Disk
The debris disk surrounding Vega serves as both a remnant of its past and a potential insight into the evolutionary pathways of stellar systems. While Vega has successfully transitioned beyond the protoplanetary phase, the absence of planet formation has raised questions about the dynamics and conditions necessary for such processes to occur. The interplay between the star’s gravitational influence and the dust and debris could play a substantial role in either facilitating or hindering the formation of planets.
Through ongoing investigations using the James Webb Space Telescope, scientists hope to gather more data on the composition and behavior of the particles within Vega’s debris disk. This will help them to understand whether this mysterious star has simply missed out on the opportunity for planetary formation or if there are underlying mechanisms at work that prevent it from forming planets.
Conclusion: Vega’s Role in Cosmic Understanding
Vega stands as a unique and significant case study in the field of astrophysics. Its peculiar characteristics challenge prevailing theories about how and when planetary systems form. By observing and analyzing Vega, researchers are not only hoping to unravel the mysteries surrounding this star but also to gain general insights into the complexities of cosmic evolution.
As we continue to observe and learn about Vega, it offers a tantalizing glimpse into the variety of stellar outcomes that can arise in the universe. The universe clearly enjoys throwing us curveballs, and Vega is as enigmatic as they come. Perhaps one day, this star will reveal its secrets and shed light on the mysteries of planetary formation for all of us avid cosmic explorers.
