### Astronomers Uncover a Rare “Ultra-Hot Neptune” in the Cosmos

Far outside our solar system, astronomers have discovered a variety of **super-Earths**, **mini-Neptunes**, and **hot Jupiters**. Yet, they have identified an **”ultra-hot Neptune”** only once—a Neptune-sized exoplanet orbiting very close to its host star.

This unusual exoplanet, termed **LTT 9779 b**, completes an entire orbit in under one day. Since its discovery in 2020, researchers have utilized the **James Webb Space Telescope** to examine its atmosphere and understand how such an extraordinary planet operates.

*”Locating a planet of this size in such proximity to its star is akin to finding a snowball that hasn’t melted amidst flames,”* remarked Louis-Philippe Coulombe, a researcher at the Université de Montréal’s Trottier Institute for Research on Exoplanets, who spearheaded the study. *”It showcases the incredible variety of planetary systems and aids in our understanding of planetary evolution under extreme conditions.”*

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### A Scorching, Tidally Locked Planet

LTT 9779 b is an extreme world, nearly **30 times heavier than Earth**. It is **tidally locked** to its star—parallel to how the **Moon is locked to the Earth**—resulting in one side being perpetually exposed to intense warmth while the opposite side remains shrouded in darkness.

The planet’s **dayside experiences searing temperatures of 3,630 degrees Fahrenheit (2,000 Celsius)**—hotter than molten rock. To investigate this remarkable planet, scientists monitored it for **22 hours** using Webb’s **spectrograph**, an apparatus designed to analyze light and ascertain the composition of remote atmospheres.

Their results indicated the presence of **clouds composed of silicates**—the minerals that form rocks on Earth—rather than water vapor. These clouds were found on the planet’s **western dayside**, while the **hotter eastern hemisphere stayed cloudless**, implying that **strong winds** are shifting atmospheric components across the planet.

An artistic illustration of **LTT 9779 b**, situated **262 light-years away in the Milky Way**, depicts how **highly reflective silicate clouds** condense on the **cooler western side** and evaporate as they travel to the **warmer eastern hemisphere**.

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### Unraveling the Secrets of LTT 9779 b

Researchers are just beginning to grasp this unique exoplanet.

*”We haven’t fully assembled the data regarding this planet yet,”* commented Jake Taylor, a physicist at the University of Oxford who was involved in the study. *”We are currently utilizing information from the Hubble Space Telescope and the Very Large Telescope to investigate the planet’s cloud structure in more detail.”*

To date, astronomers have confirmed **5,834 exoplanets**, with countless more awaiting validation.

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### The James Webb Space Telescope’s Innovative Capabilities

The **James Webb Space Telescope**—a joint venture between **NASA, ESA, and the Canadian Space Agency**—is engineered to probe the **farthest reaches of space** and unveil secrets about the **early universe**. It also explores **exoplanets** and celestial objects within our own **solar system**.

Here’s how Webb is transforming space exploration:

– **Large Mirror:** Webb’s **21-foot-wide mirror** is over **2.5 times bigger** than that of the **Hubble Space Telescope**, allowing it to capture six times more light. This grants Webb the ability to study **distant galaxies** formed over **13 billion years ago**, shortly following the **Big Bang**.

– **Infrared Capability:** Unlike Hubble, which primarily detects **visible light**, Webb operates in the **infrared spectrum**. Infrared light possesses **longer wavelengths**, enabling it to **traverse cosmic dust clouds** and uncover hidden celestial bodies.

– **Exoplanet Atmospheric Examination:** Webb’s **spectrographs** can identify molecules like **water, carbon dioxide, and methane** in the atmospheres of far-off exoplanets. This feature may assist scientists in assessing whether some of these worlds could be **habitable**.

As Webb advances in its mission, astronomers expect **groundbreaking revelations** that could redefine our comprehension of the universe.

*”We might discover aspects we never even contemplated,”* noted Mercedes López-Morales, an exoplanet researcher at the **Center for Astrophysics-Harvard & Smithsonian**.