{"id":398031,"date":"2026-04-18T02:52:16","date_gmt":"2026-04-18T02:52:16","guid":{"rendered":"https:\/\/www.newsbeep.com\/il\/398031\/"},"modified":"2026-04-18T02:52:16","modified_gmt":"2026-04-18T02:52:16","slug":"less-than-1-of-red-giant-stars-still-have-planets-orbiting-them","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/il\/398031\/","title":{"rendered":"Less than 1% of red giant stars still have planets orbiting them"},"content":{"rendered":"

A new study has found that close-orbiting giant<\/a> planets nearly vanish as stars expand into red giants, dropping to just 0.11% around the most evolved stars.<\/p>\n

That collapse reveals a widespread process in which aging stars pull nearby planets inward and destroy them rather than simply hiding them from view.<\/p>\n

The missing worlds
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Across 456,941 aging stars observed by the Transiting Exoplanet Survey Satellite, TESS, the missing planets showed up as an absence, not a flash.<\/p>\n

Reading those patterns, Dr. Edward Bryant at University College London (UCL<\/a>) found that the nearest giant planets were disappearing fastest.<\/p>\n

Rather than fading evenly, the count fell hardest once the stars had cooled and expanded enough to count as red giants.<\/p>\n

That trend pointed away from chance and toward a physical process that steadily clears close orbits as stars swell.<\/p>\n

Why planets fall<\/p>\n

As a star grows, a tidal interaction, a mutual pull that drains orbital energy, grips an orbiting giant planet ever harder.<\/p>\n

With each lap around the star, the planet loses a little speed and drops into a tighter path.<\/p>\n

Long before the star reaches its biggest size, that inward drift can tear a planet apart or dump it into the star.<\/p>\n

\u201cWe expected to see this effect but we were still surprised by just how efficient these stars seem to be at engulfing their close planets,\u201d said Dr. Bryant.<\/p>\n

Hunting faint dips<\/p>\n

NASA\u2019s TESS<\/a> watched for repeated dimmings in starlight as planets crossed in front of their stars.<\/p>\n

Because swollen stars are large, the transits can last a long time and look broader than usual.<\/p>\n

The team therefore tailored its search to short-period giant planets that circled in 12 days or less.<\/p>\n

That focus kept the study on the worlds most exposed to the growing pull of an aging star.<\/p>\n

Sifting real worlds<\/p>\n

More than 15,000 likely signals eventually shrank to 130 surviving planets or planet<\/a> candidates, including 33 not reported before.<\/p>\n

Some apparent dips came from eclipsing star pairs or from light leaking in from nearby stars.<\/p>\n

To sort possible planets from look-alikes, the researchers checked whether signals repeated cleanly, matched each star, and stayed centered on the target.<\/p>\n

That caution matters because a false planet can easily distort the population picture the study was built to measure.<\/p>\n

Rates that plunge<\/p>\n

Overall, just 0.28% of the surveyed stars held close giant planets once the team corrected for missed detections.<\/p>\n

Among the less evolved stars, the rate was 0.35%, which looked much like comparable stars before swelling began. By the time stars reached early red giant status, the figure had dropped to 0.11%.<\/p>\n

Those numbers turned a long-argued idea into a measurable population effect, not just a story built from individual systems.<\/p>\n

The shortest orbits<\/p>\n

The sharpest losses appeared among planets that whipped around their stars in less than about six days.<\/p>\n

At those distances, the gravitational tug works faster, because a nearby planet raises stronger tides on the star<\/a>.<\/p>\n

Farther out, giant planets still looked reduced, but the drop was smaller and harder to separate from random scatter.<\/p>\n

That period dependence is one reason the team argues the planets are being dragged inward, not merely overlooked.<\/p>\n

Our distant future<\/p>\n

Our own Sun is expected to remain stable for about five billion more years before becoming a red giant.<\/p>\n

Unlike the giant planets in this survey, Earth sits much farther out and was not the kind of world studied here.<\/p>\n

Even so, the paper followed only the first one or two million years of this swollen stage.<\/p>\n

That leaves room for Earth to avoid being swallowed while still becoming utterly hostile to life long before then.<\/p>\n

What remains uncertain<\/p>\n

Many of the objects are still candidates, which means astronomers know their size but not yet what they weigh.<\/p>\n

Using radial velocity, the back-and-forth motion seen in starlight, astronomers can confirm real planets and measure their pull.<\/p>\n

With brighter targets now in hand, UCL and other teams can test the picture much more directly.<\/p>\n

\u201cOnce we have these planets\u2019 masses, that will help us understand exactly what is causing these planets to spiral in and be destroyed,\u201d Bryant said.<\/p>\n

Beyond one disaster<\/p>\n

Astronomers have already seen a dramatic engulfment<\/a> when one distant star apparently swallowed a Jupiter-size planet.<\/p>\n

What TESS adds here is scale, showing that quieter destruction seems to happen across many systems, not only as a rare outburst.<\/p>\n

Population studies like this matter because they reveal what single spectacular events cannot, namely how common the damage becomes.<\/p>\n

That wider view turns dying planetary systems from isolated curiosities into a visible part of how ordinary stars age.<\/p>\n

Planetary systems do not simply coast into old age, because swelling stars keep rewriting the nearest orbits.<\/p>\n

Better mass measurements should now show which giants still have time left and which are already falling in.<\/p>\n

The study is published in Monthly Notices of the Royal Astronomical Society<\/a>.<\/p>\n

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