Science & Tech · Space · 1 day ago
Study rules out Jupiter-sized planets in parts of the 70 Ophiuchi system
70 Ophiuchi AB is a pair of stars about 16 light-years from Earth.
Astronomers have wondered since 1855 whether a planet orbits the system, but an early claim was later rejected.
A new study led by University of Michigan researchers found no giant planets in the regions they examined.
The team used a century of data and new telescope observations to study a wobble in the stars’ motion.
That wobble could have come from a planet’s gravity, but the researchers concluded that changing activity on the stars’ surfaces explained it.
They ruled out planets at least as massive as Jupiter within 5 astronomical units of star A, and within half an astronomical unit of star B. This narrows where giant planets could be and can help guide future searches for smaller worlds, including planets in habitable zones.
A University of Michigan-led study found no giant planets in the regions it examined around the two stars of 70 Ophiuchi AB.
The researchers ruled out planets at least as massive as Jupiter within 5 astronomical units of 70 Oph A and within half an astronomical unit of 70 Oph B.
The study concluded that variations on the stars’ surfaces, rather than a planet, could explain a wobble seen in measurements of the stars.
The findings refine where astronomers can search for smaller planets in the nearby two-star system.
70 Ophiuchi AB is about 16 light-years from Earth and has been discussed as a possible home for a planet since 1855.
- Who
- Researchers led by the University of Michigan, including postdoctoral researcher Yiting Li.
- What
- The study ruled out planets at least as massive as Jupiter in specified regions around both stars.
- When
- Published in The Astrophysical Journal; the publication date is not stated.
- Where
- In the 70 Ophiuchi AB system, about 16 light-years from Earth.
- Why
- The researchers determined that changes on the stars’ surfaces could explain a wobble previously considered a possible planet signal.
This story does not have two clearly opposing sides.
It’s a cautionary tale about how stellar activity can mimic planet signals using the radial velocity.
British astronomer William Jacob claimed that a planet might orbit 70 Ophiuchi AB.
University of Michigan researchers reported that stellar surface variations could explain the observed wobble and ruled out Jupiter-mass planets in specified regions.
- Distance from Earth
- About 16 light-years
- Limit around 70 Oph A
- Planets at least as massive as Jupiter ruled out within 5 astronomical units
- Limit around 70 Oph B
- Planets at least as massive as Jupiter ruled out within half an astronomical unit
- Key researcher
- Yiting Li, University of Michigan postdoctoral researcher
- Journal
- The Astrophysical Journal









