Одон орон судлаачид хэт нягт ихтэй гэгддэг найман экзопланетын жинхэнэ массыг эх одны идэвхжил төөрөгдүүлж байгааг тогтоов.
Судлаачид Кэйси Бринкман болон Николас Коуан нар 2026 оны аравдугаар сарын 8-нд arXiv санд нийтэлсэн судалгаагаараа зарим том хэмжээтэй, хатуу гадаргуутай гаригуудын масс хэт өндөр үнэлэгдсэн байж болзошгүйг тайлбарлажээ. Онолын хувьд 10 орчим Дэлхийн масстай гаригууд хүрээлэн буй хийн дискнээс их хэмжээний хий татаж авах ёстой ч, ажиглагдсан зарим гариг ийм хийн бүрхүүлгүй хэрнээ ер бусын нягттай байгаа нь эргэлзээ төрүүлж байв.
Судлаачид NASA-гийн Exoplanet Archive-д бүртгэлтэй 333 экзопланетыг шинжилсний эцэст найман гаригт анхаарлаа хандуулжээ. Эдгээр гаригийн масс нь ихэвчлэн радиаль хурдны аргаар (одон орон судлаачид гаригийн таталцлаас үүдэлтэй одны хэлбэлзлийг хэмжих арга) тодорхойлогддог байна. Гэвч шинжилгээгээр эдгээр найман гариг бүгд соронзон идэвхжил өндөртэй оддыг тойрон эргэдэг болох нь тогтоогджээ.
Одны гадаргуу дээрх харанхуй толбо болон соронзон бүсүүд нь одны эргэлтийн үед гэрлийн хэмжилтэд нөлөөлж, гаригийн таталцлын дохиотой төстэй хуурамч үзүүлэлтүүдийг үүсгэдэг байна. Тухайлбал, HD 63433 b гаригийн массыг нэг судалгаагаар 37 Дэлхийн масстай гэж тооцоолсон бол өөр нэг шинжилгээгээр 21 орчим Дэлхийн масстай гэж гарчээ. Энэхүү соронзон идэвхжил нь гаригийн жинхэнэ массыг хиймлээр өсгөж харагдуулж байж болзошгүйг эрдэмтэд онцлов.
Одоогийн байдлаар 10 Дэлхийн масстай хатуу гадаргуутай гариг үүсэх боломжтой гэх нотолгоо хангалтгүй байгаа бөгөөд эдгээр “мега-Дэлхий” гаригуудын массын хэмжилтүүд нь одны идэвхжилийн улмаас найдвартай бус байж магадгүй юм. Иймд одон орон судлаачид одны идэвхжлийг гаригийн таталцлын дохионоос тусгаарлахын тулд илүү ойр давтамжтайгаар ажиглалт хийх шаардлагатай гэж зөвлөж байна.
Дэлгэрэнгүйг эх сурвалжаас харах
↓Эх сурвалжийг нээх ↓
Some of the biggest rocky planets ever discovered might not be quite what they seem. A new study suggests that activity on their host stars could be making eight unusually dense planets look much heavier than they really are. And that raises a big question: do these so-called mega-Earths actually exist?
Rocky planets aren’t supposed to grow endlessly. Once they reach around 1.5 to 1.75 times Earth’s radius, or roughly four to five Earth masses, they tend to start building up thick gas envelopes. And when a planet reaches about 10 Earth masses, its gravity should be strong enough to pull in large amounts of gas from the disk around its young star.
But a handful of planets seem to break that rule. They’re surprisingly massive for their size, yet appear to contain little or no hydrogen-helium gas. A study by Casey Brinkman and Nicolas Cowan, posted on arXiv on October 8, 2026, offers a simpler explanation: astronomers could be overestimating their masses.
Eight Strange Planets Have Something In Common
To investigate, the researchers turned to NASA’s Exoplanet Archive and examined planets smaller than four times Earth’s radius. They focused on worlds whose masses had been measured using the radial-velocity method, which tracks the tiny movements a planet causes in its host star. After removing planets with less reliable measurements, they were left wxith 333 exoplanets, eight stood out.
Four planets, WASP-84 c, TOI-1347 b, TOI-2322 c, and HD 63433 b, had masses consistent with rocky mega-Earths. A further four, GJ 523 b, TOI-815 c, HD 18599 b, and GJ 143 b, also showed anomalously high densities, but their compositions could include water or other dense constituents. The analysis then shifted to the properties of the host stars.
Using magnetic activity indicators based on calcium spectral lines and brightness measurements from NASA’s TESS spacecraft, they found something unexpected: all eight planets orbit magnetically active stars.
The numbers made that connection even more interesting. The chance of finding the four rocky mega-Earths around active stars was only about 1%. For all eight unusually dense planets, it dropped to a fraction of a percent.
Are Stars Distorting the Data?
Astronomers can’t simply put an exoplanet on a scale. Instead, they often calculate its mass by watching how its gravity makes its star wobble. The problem? Stars can create misleading signals of their own.
Dark starspots and brighter magnetic regions move across a star’s surface as it rotates. These changes can affect the light astronomers analyze, sometimes producing signals that look remarkably similar to those caused by orbiting planets. That makes it harder to separate a planet’s gravitational pull from the activity of its star.
Brinkman and Cowan found that the problem becomes particularly difficult when a planet’s orbital period is close to its star’s rotation period. Take HD 63433 b, for example. One research team estimated its mass at around 37 Earth masses. Another analysis came up with roughly 21 Earth masses.
The researchers also found that, for three planets, the signals were too weak compared with stellar noise for a standard statistical modeling technique to recover them reliably.
“The most likely culprit for these larger-than-expected masses is artificial inflation from stellar activity,” they wrote.
So, Are Mega-earths Actually Real?
There’s another detail that makes these planets puzzling: their stars are active. Younger stars tend to be more magnetically active, but there’s no clear reason why unusually massive rocky planets should be more common around them.
If anything, some proposed formation scenarios suggest the opposite. Building a giant rocky planet through repeated collisions after the surrounding gas disk disappears could take longer, making older systems more likely places to find them. The study found no compelling evidence that rocky planets really form beyond approximately 10 Earth masses.
That doesn’t mean mega-Earths have been ruled out. It means the measurements behind some of the strongest candidates may not be as reliable as they first appeared. The team recommends taking more frequent radial-velocity measurements, with shorter gaps between observations, to better track stellar activity and separate it from planetary signals.
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