Jupiter-like exoplanet orbiting nearby star detected
by Tomasz Nowakowski, Phys.org
Israeli astronomers report the detection of a new Jupiter-like exoplanet using the High Accuracy Radial velocity Planet Searcher (HARPS). The newfound alien world orbits a nearby M-dwarf star designated GJ 2126. The discovery was announced in a research paper published Feb. 16 on the arXiv pre-print server.
The radial velocity (RV) method of detecting an exoplanet is based on the detection of variations in the velocity of the central star, due to the changing direction of the gravitational pull from an unseen exoplanet as it orbits the star. Thanks to this technique, more than 600 exoplanets have been detected so far.
| Parameter | Value |
|---|---|
| Star Name | GJ 2126 |
| Exoplanet Name | GJ 2126 b |
| Orbital Period | 272.7 days |
| Eccentricity | 0.85 |
| Mass | ≥ 1.3 Jupiter masses |
HARPS is a high-resolution visible-light echelle spectrograph installed at the European Southern Observatory (ESO) 3.6-m telescope in Chile. Thanks to its radial-velocity accuracy of about 1 m/s, it is one of the most successful planet finders in history.
Now, a team of astronomers led by Arbel Schorr of the Tel Aviv University in Israel has found another planet based on RV measurements from the HARPS-RVBank database, which contains over 250,000 RVs of 5,239 stars. The HARPS-RVBank database includes all stellar spectra obtained with the HARPS instrument prior to January 2022, available for astronomers to confirm or discover planet candidates.
| Observation Method | Description |
|---|---|
| Radial Velocity | Detection of variations in the velocity of the central star due to gravitational pull from orbiting exoplanets. |
| HARPS Specifications | Installed at the European Southern Observatory, provides high-accuracy measurements. |
| HARPS-RVBank | Database containing RV measurements, assisting in planet detection and analysis. |
"We report the discovery of GJ 2126 b, a highly eccentric (e = 0.85) Jupiter-like planet orbiting its host star every 272.7 days. The planet was detected and characterized using 112 RV measurements from HARPS, provided by HARPS-RVBank," the researchers wrote in the paper.
The study found that GJ 2126 b orbits its host star at a separation of 0.71 AU from it. The planet's mass is estimated to be at least 1.3 Jupiter masses. However, given that the inclination of GJ 2126 b is unknown, its mass could be much greater and the possibility that this object may be a brown dwarf cannot be completely excluded.
| Host Star Characteristics | Value |
|---|---|
| Type | M0V |
| Radius | 0.73 solar radii |
| Mass | 0.65 solar masses |
| Distance | 124 light years |
| Effective Temperature | 4,159 K |
Astronomers underline that GJ 2126 b is one of the most eccentric exoplanets discovered around an M-dwarf. They added that the unique properties of GJ 2126 b place it in a relatively sparse region of the detected exoplanet population. Therefore, its further observations could help better understand planetary formation and evolution scenarios.
Further observations of GJ 2126 b are required in order to determine its radius and to constrain its mass, which would shed more light regarding the composition of this exoplanet.
This discovery opens new doors to understanding the dynamics of exoplanets around M-dwarfs, paving the way for future explorations in the field of planetary sciences. – Dr. Arbel Schorr, Lead Researcher
More information: Arbel Schorr et al, GJ 2126 b: A highly eccentric Jovian exoplanet, arXiv (2025). DOI: 10.48550/arxiv.2502.11139
Journal information: arXiv
