Discovery of Low-Density Exoplanets TOI-791 b and TOI-791 c Using TESS Data
利用 TESS 數據發現低密度系外行星 TOI-791 b 與 TOI-791 c
Introduction
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。
Main Body
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。
Conclusion
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。
Vocabulary Learning
🚀 The 'Precision Gap': Moving from A2 to B2
At an A2 level, you describe things using simple words like very small or not much. To reach B2, you need Precision. Look at how this text describes the planets. It doesn't just say they are "light"; it calls them "low-density" and "super-puffs."
🔍 The Magic of "Compound Modifiers"
B2 speakers combine words to create specific descriptions. Instead of saying "planets that have low density," the author uses low-density as an adjective.
- A2 Style: The star is like the Sun. B2 Style: A Sun-like star.
- A2 Style: Disks that have a lot of gas. B2 Style: Gas-rich disks.
- A2 Style: Observation for a long time. B2 Style: Long-term observation.
🛠️ How to apply this now
Stop using "very" + [simple adjective]. Try to find a compound word or a specific technical term.
Example: Instead of saying "This is a very old-fashioned house," try "This is a traditional-style house."
💡 Logical Connectors (The Glue)
Notice the word "Consequently." An A2 student uses "So..."
- So, they will use the telescope.
A B2 student uses "Consequently" or "Therefore" to show a professional cause-and-effect relationship:
- Consequently, they now plan to use the James Webb Space Telescope.
Pro Tip: Use "Consequently" when you want to sound more academic or formal in a report or presentation.