Scientists found two very light planets. They call these planets 'super-puffs'. They move around a star called TOI-791.

科學家發現了兩顆非常輕的行星，他們將這些行星稱為「超級蓬鬆行星」（super-puffs）。這些行星圍繞著一顆名為 TOI-791 的恆星運行。

A space telescope called TESS found these planets. The star is very far from Earth. The two planets are big in size, but they have very little weight. They are much lighter than the planet Jupiter.

一台名為 TESS 的太空望遠鏡發現了這些行星。該恆星距離地球非常遙遠。這兩顆行星體積龐大，但重量極輕，比木星輕得多。

These planets are very rare. Scientists know many planets, but only a few are 'super-puffs'. It is very unusual to find two of them together.

這些行星非常罕見。科學家雖然已知許多行星，但只有少數是「超級蓬鬆行星」。能同時發現兩顆這樣的行星是非常不尋常的。

Many universities worked together on this study. Now, scientists want to use a bigger telescope. They want to see what gases are in the air of these planets.

許多大學共同參與了這項研究。現在，科學家希望使用更大的望遠鏡，以觀察這些行星的大氣層中包含哪些氣體。

These planets help scientists understand how planets start and change.

這些行星有助於科學家了解行星是如何形成與演變的。

Astronomers have discovered two extremely low-density planets, known as 'super-puffs,' which orbit the star TOI-791.

天文學家發現了兩顆密度極低的行星，被稱為「超級棉花糖」行星（super-puffs），它們繞著恆星 TOI-791 運行。

The Transiting Exoplanet Survey Satellite (TESS) detected TOI-791 b and TOI-791 c by recording regular drops in the brightness of their host star over seven years. This Sun-like star is located about 1,110 to 1,113 light-years from Earth. Although both planets are similar in size to Jupiter, they have very little mass; TOI-791 b has only 3.0% of Jupiter's mass, while TOI-791 c has 5.9%. Researchers calculated these masses by analyzing how the planets' gravity affected each other's orbital timing.

凌日系外行星巡天衛星（TESS）透過記錄母恆星在七年內定期出現的亮度下降，偵測到了 TOI-791 b 與 TOI-791 c。這顆類太陽恆星距離地球約 1,110 至 1,113 光年。雖然兩顆行星的大小與木星相似，但質量非常輕；TOI-791 b 僅有木星質量的 3.0%，而 TOI-791 c 則有 5.9%。研究人員透過分析行星的重力如何影響彼此的軌道時間，計算出這些質量。

These planets have unusual orbital periods of 139 and 232 days, which means they required long-term observation to be confirmed. Such systems are very rare, as fewer than 40 super-puff planets have been found among nearly 6,300 known exoplanets. Furthermore, finding two of them in one system is highly unusual. Scientists believe these planets formed from gas-rich disks around young stars and lost much of their material over time.

這些行星具有不尋常的公轉週期，分別為 139 天與 232 天，這意味著需要長期觀察才能確認。此類系統非常罕見，因為在近 6,300 顆已知系外行星中，發現的「超級棉花糖」行星不足 40 顆。此外，在同一個系統中發現兩顆更是極其罕見。科學家認為這些行星形成於年輕恆星周圍富含氣體的盤狀結構，並隨時間流逝失去了大部分物質。

This research was a collaboration between the University of Oxford, the University of Birmingham, and the Université Côte d’Azur. The team published their results in the Monthly Notices of the Royal Astronomical Society. Consequently, they now plan to use the James Webb Space Telescope to check if the atmospheres consist mainly of hydrogen and helium and to study how the planets moved into their current orbits.

這項研究是由牛津大學、伯明翰大學與蔚藍海岸大學共同合作。團隊將結果發表於《皇家天文學會月報》。因此，他們目前計劃使用詹姆斯·韋伯太空望遠鏡來檢查大氣層是否主要由氫與氦組成，並研究這些行星如何移動到目前的軌道。

The discovery of these low-density planets provides important new data for understanding how planets form and change over time.

發現這些低密度行星，為我們理解行星如何形成以及隨時間演變提供了重要的新數據。

Astronomers have identified two exceptionally low-density planets, designated as 'super-puffs,' orbiting the star TOI-791.

天文學家已識別出兩顆密度極低、被稱為「超級棉花糖」的行星，正圍繞恆星 TOI-791 運行。

The detection of TOI-791 b and TOI-791 c was facilitated by the Transiting Exoplanet Survey Satellite (TESS), which recorded periodic luminosity decreases of the host star over a seven-year duration. This Sun-like star, situated approximately 1,110 to 1,113 light-years from Earth in the constellation Volans, hosts two planets of Jovian dimensions but negligible mass. Specifically, TOI-791 b possesses 3.0 percent of Jupiter's mass, while TOI-791 c possesses 5.9 percent. The determination of these masses was achieved through the analysis of transit timing variations, resulting from the mutual gravitational perturbations between the two bodies.

TOI-791 b 與 TOI-791 c 的發現得益於凌日系外行星巡天衛星 (TESS)，該衛星記錄了主恆星在七年期間的週期性亮度下降。這顆類太陽恆星位於天池座，距離地球約 1,110 至 1,113 光年，擁有兩顆體積與木星相當但質量極低的行星。具體而言，TOI-791 b 的質量為木星的 3.0%，而 TOI-791 c 則為 5.9%。這些質量的確定是透過分析兩者間相互重力擾動所導致的凌日時間變化而實現的。

These celestial bodies exhibit anomalous orbital periods of 139 and 232 days, respectively. Such extended orbits necessitate prolonged observation windows for confirmation. The rarity of this system is underscored by the fact that fewer than 40 super-puff planets have been confirmed among nearly 6,300 known exoplanets. The presence of two such entities within a single system is particularly infrequent. Theoretical frameworks suggest these planets originate from gas-rich disks around nascent stars, subsequently losing significant material over time.

這些天體表現出分別為 139 天和 232 天的異常軌道週期。如此延長的軌道需要更長的觀測視窗才能予以確認。在近 6,300 顆已知系外行星中，僅有不到 40 顆被確認為超級棉花糖行星，凸顯了該系統的罕見性。單一系統中同時存在兩顆此類天體尤為罕見。理論框架認為，這些行星起源於新生恆星周圍富含氣體的星盤，隨後隨著時間流逝失去了大量物質。

Institutional collaboration involving the University of Oxford, the University of Birmingham, and the Université Côte d’Azur led to the publication of these findings in the Monthly Notices of the Royal Astronomical Society. Future research objectives include the utilization of the James Webb Space Telescope to ascertain the chemical composition of the atmospheres—hypothesized to consist primarily of hydrogen and helium—and to evaluate the influence of planetary spin and stellar tilt on orbital migration.

由牛津大學、伯明翰大學與蔚藍海岸大學參與的機構合作，將這些發現發表於《皇家天文學會月報》。未來的研究目標包括利用詹姆斯·韋伯太空望遠鏡來確定大氣層的化學組成（假設主要由氫和氦組成），並評估行星自轉與恆星傾斜對軌道遷移的影響。

The discovery of these low-density planets provides a new dataset for analyzing the mechanisms of planetary formation and evolution.

發現這些低密度行星，為分析行星形成與演化的機制提供了新的數據集。