Jupiter-Sized Exoplanet Discovered Orbiting a Sun-Like Star

Astronomers have identified a Jupiter-sized exoplanet, designated NGTS-39b, orbiting a Sun-like star. The discovery, reported on July 19, 2026, utilized data from the Next-Generation Transit Survey (NGTS) and NASA’s Transiting Exoplanet Survey Satellite (TESS) to confirm the planet’s mass and orbital characteristics.

The planet is classified as a gas giant, composed primarily of hydrogen and helium. According to the reporting from Notebookcheck, the discovery involves a star with properties similar to the Sun, providing a comparative baseline for understanding how giant planets form and migrate within solar systems that mirror our own.

Detection Methods and the Role of TESS

Researchers located NGTS-39b using the transit method, which detects a planet when it passes between its host star and the observer, causing a slight dip in the star’s brightness. This method allows astronomers to calculate the planet’s size relative to the star.

Data from NASA’s TESS mission provided the high-precision photometry needed to refine the orbital period and transit depth. TESS is designed to scan the brightest stars in the sky to find planetary candidates, which are then often verified by ground-based telescopes like those in the NGTS network.

The NGTS utilizes a series of robotic telescopes to monitor thousands of stars simultaneously. By combining these ground-based observations with space-based data, the team confirmed that the object was a planet rather than a brown dwarf or a binary star system.

Physical Characteristics of NGTS-39b

NGTS-39b is characterized by its massive scale, closely resembling Jupiter in volume. Because it orbits a Sun-like star, it serves as a critical data point for the study of “Hot Jupiters”—gas giants that orbit very close to their parent stars.

The composition of the planet is dominated by hydrogen and helium, the lightest and most abundant elements in the universe. This composition is typical for planets of this mass, which possess enough gravitational pull to capture vast amounts of gas from the protoplanetary disk during their formation.

The interaction between the planet and its Sun-like host star allows scientists to analyze the atmospheric chemistry of the exoplanet. When the planet transits, some starlight passes through its atmosphere, leaving a spectral signature that reveals which gases are present.

Context within Exoplanet Research

The discovery of NGTS-39b contributes to the broader effort to map the diversity of planetary systems. While Jupiter in our own solar system orbits far from the Sun, many discovered exoplanets of similar size are found in much tighter orbits.

According to the discovery data, the presence of a Jupiter-sized planet around a Sun-like star helps researchers test theories of planetary migration. These theories suggest that giant planets may form in the colder, outer regions of a system and later migrate inward toward the star due to gravitational interactions.

The use of multiple observation platforms—combining the wide-field survey capabilities of TESS with the targeted follow-up of NGTS—demonstrates the current standard in astronomical verification. This multi-layered approach reduces false positives and ensures the accuracy of the planet’s mass and radius measurements.