An international team of astronomers has discovered two gas giants orbiting a Sun-like star located 175 light-years away. The work could teach us a lot about star systems like our own and the possibility of finding life on other planets. Details are available on the arXiv prepress site.
Adding to the benefits are understanding the variety of systems that can orbit Sun-like stars and the growing evidence that the architecture of a planetary system plays an important role in a planet’s habitability.
The system
The presence of asteroids and comets capable of carrying certain ingredients to a planet is vital. Jupiter plays an important role in our solar system, protecting the inner system from the constant bombardment of small rocks. The gas giant herds both the asteroid belt and the asteroids that share its orbit.
However, its immense gravity can also upset the orbits of those smaller bodies, hurling them into the inner solar system. Early in the history of the solar system, Jupiter was probably instrumental in helping those rocks reach Earth.
Looking for planets similar to Jupiter is a good option. Astronomers have discovered that Jupiter analogues form preferentially around stars with near-solar metallicities.
To the surprise of scientists, potentially habitable low-mass planets could be common around stars that host a cold Jupiter. Small Earth-sized planets are more common than giant planets.
The discovery
Since 2014, astronomers led by Thiago Ferreira of the University of Sao Paulo have been searching for exoplanets around stars similar to the Sun. To do so, they used the High-Precision Radial Velocity Planet Searcher (HARPS) on the 3,000-foot La Silla telescope. 6 meters from the European Southern Observatory in the Atacama desert.
The star’s name is HIP 104045 and it appears to be a near-perfect twin of the Sun. It has nearly identical metal content, is around 4.5 billion years old, and is only 1.03 times the mass of the Sun. When the team analyzed light from HIP 104045, they found evidence of not one, but two planets.
The first is a Jupiter analogue with about half the mass of Jupiter in an orbit of 6.3 years. It orbits between 3 and 7 AU from the star, so it may play a similar important role to Jupiter in our own Solar System.
The second is a super-Neptune, with about 2.5 times the mass of Neptune in a daytime orbit of 316 days. Although it is unlikely to be a rocky world like Earth, it is located in what is known as the habitable zone.
The search for extraterrestrial life continues to be a fascinating subject for astronomers and the general public. This discovery helps us better understand how planetary systems are formed and the diversity of worlds that can host Sun-like stars. Let’s hope one day to find a second Earth.