Ravenous 'vampire' stars may use cosmic accomplices to help devour stellar victims
Astronomers have been aware of cosmic vampires, dead stars that hungrily strip plasma from victim stars, for some time. New research suggests that some of these cosmic fiends could have accomplices, Renfields to their Draculas, in the form of a third star in their systems, facilitating their fateful encounter.
These systems are known as cataclysmic variables, and their occupant vampire stars are white dwarfs, the type of stellar remnant that stars with masses around that of the sun leave behind when they die.
The matter stolen from their victim stellar companions by these white dwarfs piles up on the dead stars' surfaces, eventually causing them to go supernova and be obliterated. Though the endings of cataclysmic variables are fairly well understood, this research suggests at least one new origin story.
"Our results are revealing another formation channel for cataclysmic variables," California Institute of Technology (Caltech) researcher Kareem El-Badry said in a statement. "Sometimes, a lurking third star is key."
The current consensus on cataclysmic variables is that they form when two stars are brought together by a "common envelope" of gas wrapped around them. This is known as "common envelope evolution."
Eventually, one of these two stars swells up as a red giant, puffing out to up to 100 times its original size, swallowing its stellar companion. After this envelope causes these stars to spiral together, it is ejected. The red giant is now a stripped core called a white dwarf with a companion star close enough for the dead star to strip it of its outer layers.
While many stars exist in binaries, triple-star systems are also common in the universe. That prompted El-Badry, Caltech graduate student Cheyanne Shariat, and their team to wonder how this process would play out for three stars.
To investigate this, the duo turned to the European Space Agency (ESA) mission Gaia. Before its recent retirement, Gaia tracked billions of stars to collect data that is allowing scientists to construct a detailed 3D map of our cosmic backyard.
El-Badry and Shariat found 50 cataclysmic variables in triple-star systems in which two stars are closely partnered while a third orbits at a much wider distance.
These results suggested to the duo that around 10% of cataclysmic variables are found in triple-star systems, a percentage that would be lower if lurking third stars had no role in creating cataclysmic variables.
To confirm this connection, the astronomers ran 2,000 simulations of hypothetical triple-star systems, watching the gravitational interactions between the three stars as the systems evolved.
In 400 of the systems, cataclysmic variables were born without the common envelope phase occurring. In that 20% sample of the total simulations, it was the third star that "torqued" the main binary, forcing them together.
"The gravity of the third star causes the binary stars to have a super eccentric orbit, and this forces the companion star closer to the white dwarf," Shariat said. "Tidal forces dissipate energy and shrink and circularize the orbit. The star doesn't have to spiral in through the common envelope."
But that wasn't all. In 60% of the simulated systems, a common envelope phase did begin, and it was triggered by the third star.
In the remaining 20% of the simulations, the common envelope formed in the standard way without the third star contributing.
Adjusting their data to account for a more realistic population of stars, reflective of the Milky Way, and including known cataclysmic variables, the duo predicted 40% of cataclysmic variables form in triple systems.
That is four times higher than the Gaia sample. The team reasons that this is because many third stars in these systems were either too difficult to see or have been ejected from the system.
Related Stories:
— 'This is the holy grail of theoretical physics.' Is the key to quantum gravity hiding in this new way to make black holes?
— Tiny 'primordial' black holes created in the Big Bang may have rapidly grown to supermassive sizes
— A 'primordial' black hole may zoom through our solar system every decade
The simulations performed by El-Badry and Shariat also allowed the team to predict the type of triple-star systems more likely to form cataclysmic variables.
They found white dwarfs were more likely to feed on a stellar companion with the assistance of a third star when the system starts with the third star separated by over 100 times the distance between Earth and the sun.
Indeed, Gaia data did seem to show that triple systems with cataclysmic variables do indeed tend to display wider orbits.
"For the past 50 years, people were using the spiral-in common-envelope evolution model to explain cataclysmic variable formation," El-Badry concluded. "Nobody had noticed before that this was largely happening in triples!"
The team's research was published in the journal Publications of the Astronomical Society of the Pacific.
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
Fast Company
19 hours ago
- Fast Company
Comic-Con 2025 has arrived. Here's what to expect
Tens of thousands of fans — many in costumes — will descend Thursday on Comic-Con International, the four day pop culture spectacle that will feature updates on the new 'Predator' movie, 'Alien' series and a special appearance by George Lucas. Just don't expect major news about the future of Marvel's movie slate or what's next for the hit relaunch of DC's high-flying 'Superman' franchise. Both studios are sitting out Comic-Con 2025, as far as their film slates go. An estimated 135,000 people will attend the convention, which will greet Lucas on Sunday for his first Comic-Con appearance. The 'Star Wars' creator will discuss his new Lucas Museum of Narrative Art that will open next year in Los Angeles. Fans of the 'Alien' and 'Predator' franchises will have plenty to cheer. Elle Fanning, star of 'Predator: Badlands,' will discuss the film at Comic-Con's massive Hall H this week. FX will also bring the stars and creators of 'Alien: Earth,' a series that will unleash the Xenomorph species on Earth next month. 'Alien: Earth' will be one of the projects that brings a massive interactive experience to San Diego, with a replica of spacecraft from the series. The attraction will feature what's described as a terrifying mission at night. Marvel may not be presenting new movies, but it will have a 'Fantastic Four: First Steps' attraction near the convention, a tie-in to Friday's release of the latest attempt to successfully launch its 'first family' in theaters. Thousands of fans got a sneak peek at the convention's 460,000 square foot (42,700 square meter) exhibitor section, which features exclusive merchandise, comic book art and exhibits from brands like Star Wars, Lego, Nickelodeon, Paramount and more.
Medscape
20 hours ago
- Medscape
ASCO 2025: Melanoma TILs, Toxicity, and Diet Insights
This transcript has been edited for clarity. Welcome, everybody. My name is Teresa Amaral. Today I'm here with you to follow up on my presentation on the best of ASCO 2025. Today, we'll have two different sections. The first one is dedicated to the rapid oral communications, and the second one is dedicated to the oral communications that took place on the last day of the congress. For the rapid oral communications, we'll focus on one topic that came through three presentations, tumor-infiltrating lymphocyte (TIL) therapy. Then we will look into a very interesting aspect: the reduction in toxicity associated with immunotherapy that we know is an important aspect for patients that need to receive immunotherapy. And finally, we'll look into a potential modifiable factor that might be associated with better outcomes in patients receiving immunotherapy, which is a diet rich in fiber. In the oral communications, we'll focus on the adjuvant trials — two of them that were quite important to be presented in this session. Then [I'll discuss] a trial that dealt with an unanswered question, which is how long should we treat patients in the metastatic setting. And finally, we will look into two different trials. The first one was on sequencing therapy, which was the DREAMseq trial on the final analysis, and then [there was] a specific analysis for patients that have symptomatic brain metastases, which are still a population of patients that unfortunately are excluded from the majority of clinical trials despite the fact that they do not a very good outcome. Starting with the TIL therapy, the first trial or the first presentation that I want to show you is a new way of applying TIL therapy. Basically, this is a new engineered TIL cell therapy that is intended to be given to patients that already received immune checkpoint inhibitors — so [patients] that are resistant to this therapy. But the interesting part of this type of therapy is that it doesn't require giving interleukin-2, and it also is possible to be given with a low dose of lymphodepletion. This is one of the reasons why I decided to bring this study because we know that TIL therapy might have a good outcome in the long run and these are the results that we are going to discuss in the next presentation. One of the problems is the toxicity that is associated with the pre-therapy and the after-therapy that we need to give to these patients, which includes this lymphodepleting chemotherapy and then the interleukin-2. What these very preliminary data showed is that it is indeed feasible to do this type of therapy by not giving interleukin-2 and reducing the lymphodepleting chemotherapy, and that the overall response rate was quite reassuring because we have an overall response rate that is around 67%. The median duration of response was not reached. Of course, we will need to wait for further data because this phase 1/2 trial is recruiting and we will need to confirm this data further in a broader population with more patients. But I think these results are quite reassuring and will maybe allow us to give this type of therapy to a broader spectrum of patients, as we don't need to have fitter patients to receive this therapy because we have low toxicity. The next discussion, or the next work, that was presented was indeed quite interesting because it looked into the 5-year-old outcome of another TIL product that is called lifileucel. Basically, what the authors showed was that this one-time therapy that was given was able to demonstrate durable and deepening responses in patients with advanced melanoma. It was also interesting to see the long-term toxicity is not more than what we saw before, because the toxicity is mostly associated with the interleukin-2 and lymphodepleting chemotherapy that is necessary to give with this product. So in line with what we discussed in the previous work, this is one of the reasons why most patients, or some patients, cannot receive this type of therapy. What we saw was that after 5 years, approximately 20% of the patients remained alive. Obviously, the best outcomes are seen in the patients that do respond. If the patient responds, the chances that they have a long-term outcome are significant, which is expected. So, the other side shows that this might be feasible, at least for approximately one fifth of the population. Another point that I would like to go through with you is that we saw two works looking into TILs that are definitely a potential therapeutic option for patients that received therapy in the first line, or patients that did not benefit from immunotherapy in the first line. The third work that I would like to discuss with you is the fact — and it was also presented in these rapid oral communications — that indeed not all TILs that we give to patients are the same. What the authors from this work looked into are the infusion product characteristics that are able to predict the response of patients that are treated with TILs. What they showed is the TIL persistence and also the distinctive TIL population in terms of immunophenotypic features, in terms of the proportion of CD8+ T cells, and the high surface expression of LAG3+. All of these characteristics are associated with improved TIL outcomes in patients with metastatic melanoma, meaning that not everything that we infuse that are called TILs work exactly the same and have the same influence, let's say, on the patient's response. This is obviously important because in the future, we might need to concentrate on some strategies, or on other strategies, that modulate ex vivoTIL expansion, so that we have the optimal TIL phenotype associated with better outcomes and we make sure the TILs that we are giving to our patients are the ones that will most likely produce a better outcome — a longer response, but a more durable response. I found this work quite interesting because it's always nice and important to look into these details and understand exactly what we are treating our patients with and how these treatment characteristics influence the patient's outcomes. The second point I would like to discuss with you is the toxicity that I mentioned in the very beginning. We treat a significant amount of patients with immunotherapy, but we know that one of the problems of immunotherapy is the toxicity associated with the therapy. Several strategies are being investigated to reduce the toxicity associated with immunotherapy. One of the strategies that was presented this year is looking into interleukin-6 receptor blocking with an antibody called sarilumab. This was tested in patients that received a combination of ipilimumab, nivolumab, and relatlimab — patients with resectable stage III or stage IV melanoma. Basically, what the author showed was that indeed it was possible to reduce the toxicity associated with this triple combination. Not only did this reduce the grade 3 to grade 5 immune-related adverse events to 12% when we use this interleukin-6 receptor inhibitor, but it also resulted in the best overall response rate being more than 60% — 64%, approximately. This means that it might not only be able to reduce the severe toxicity, so grade 3 and grade 4 adverse events, but also allow patients to have a long-term benefit — especially because this is one of the highest overall response rates that we saw recently in terms of combination of immunotherapy. Obviously, these data need to be confirmed by a larger trial looking into whether this triple combination with, or without, this interleukin-6 receptor inhibitor allows lower toxicity and the high response rate we saw in this smaller trial. Finally, for the rapid oral communications, I would like to show you a trial that looks into acting on some potential modulated factors, including the diet of the patients that we treat with immune checkpoint inhibitors. This was a randomized phase 2 trial that looked into a high-fiber diet intervention in patients who received immune checkpoint inhibitors. What they showed is that it is feasible to do these kinds of studies, but it's quite challenging, especially because some patients progressed earlier or abandoned the study due to other aspects that did not really have to do with the diet itself. Giving this high-fiber diet is safe and it's also well tolerated, and it seems that this high-fiber diet might lead to improved responses in patients receiving immune checkpoint inhibitors. I must say that it might lead [to these responses], only because these are very preliminary data and they need some kind of confirmation before we start prescribing high fiber diets to all patients that are receiving immune checkpoint inhibitors. I think it's very interesting that these types of factors are being analyzed and are being discussed and investigated because these might be, I would say, simple changes that we can make in order to improve the patient's outcomes to the current therapies that we offer them anyhow. Moving into oral communications, I will start by looking into the adjuvant trials. Two important adjuvant trials were discussed. The first one was RELATIVITY-098. This was a trial that investigated programmed cell death protein 1 (PD-1) monotherapy vs PD-1 plus a LAG-3 inhibitor in the adjuvant setting. Unfortunately, the trial was negative, but I think it's very important that we show these negative trials because it allows us to understand what happened and prevents other companies or other groups from looking at the same question exactly the same way, because the reasons, or the potential reasons, for the failure of the trial were not known or were not published. I think it's very important that these negative data are presented so that we can all learn and avoid repetition of the same issues. Basically, the combination did not improve relapse-free survival compared to the monotherapy, although there were no new safety data. Interestingly enough, from the biomarker analysis and the preliminary analysis that was presented, the message came out that for this combination to work, it may be necessary for some tumor cells to be present and not completely excised, as was [the case] in this setting. These comparisons were made with the same combination in the metastatic setting, where the combination was better than immunotherapy. This kind of analysis is always interesting to look into because it might give us some hints on where we can move with this combination in the future.
Associated Press
20 hours ago
- Associated Press
Leaping sturgeon provide a show for nature lovers on Maine rivers
AUGUSTA, Maine (AP) — The Kennebec River in Maine's capital city of Augusta is known for its population of Atlantic and shortnose sturgeon. The fish sometimes leap completely from the water, as at least one did on Wednesday. The shortnose population on the river nearly doubled from about 5,100 in the late 1970s to more than 9,400 around 2000, and it has likely grown since, state biologists have said. The ancient fish have also shown signs of recovering elsewhere in Maine, such as the Saco River further south. Scientists have proposed a number of reasons why sturgeon jump out of the water, including regulating their swim bladder, communicating with other sturgeon, shedding parasites and avoiding predators. Shortnose sturgeon can weigh up to 60 pounds (27 kilograms), while Atlantic sturgeon can be much larger, with some weighing as much as 800 pounds (363 kilograms). The fish thrill nature lovers who are fortunate to catch their sudden leaps along Maine rivers. Catching a glimpse of them is often a matter of luck.
