Scientists tracked faint signals from the stars — and may have turned up hundreds of undiscovered planets
Scientists have found a potential shortcut to identifying stars that host planets. The technique, based on specific signals from starlight, could make the search for exoplanets easier, according to a new study.
The team has already used its new method to discover half a dozen previously unknown planets – but because most alien worlds are very close to their stars, they are unlikely to be habitable, the study authors say.
But this clutter could help astronomers identify stars that host undiscovered exoplanets orbiting close to their stars. This is because the debris, which is mainly a mixture of different gases, absorbs some of the light from its parent star at specific visible frequencies.
“This absorption could make the star appear artificially [magnetically] less active,” Matthew standingresearcher at European Space Astronomy Center of the European Space Agency in Madrid and the lead author of the new study, told Live Science via email. In other words, magnetically inactive stars are potentially good targets in the search for nearby, ruined exoplanets.
If this hypothesis is confirmed, planetary searches could be less random.
Star Signals
To test this idea, Standing and an international team of collaborators first identified a set of 24 stars with apparently low magnetic activity as part of the study. Dispersed Matter Planet Project (DMPP), including a handful of stars that the DMPP had analysis in 2020. The researchers then collected visible light spectra – the light curves that correspond to the wavelengths of electromagnetic radiation that humans can see – from these stars, using centrally located telescopes. European Space Observatory in Chile.
They observed each star at least 10 times for up to two weeks. If a star hosted one or more planets, its gravitational “tugs” on its star would cause it to wobble, which would be visible in the spectra. (This method of identifying exoplanets is called radial velocity technique.)
Next, the team used a computer algorithm to determine whether such changes in light curves could correspond to four planets for each star system. The analysis also allowed researchers to determine the sensitivity of the survey and the frequency of nearby planets around stars with low levels of magnetic activity.
The results, published on February 28 in the journal Monthly Notices of the Royal Astronomical Societyshowed that 14 stars hosted a total of 24 exoplanets, including a total of seven newly discovered worlds in five of these systems.
The team also calculated that the presence of exoplanets around the selected stars was between eight and ten times higher than in other radial velocity surveys. This occurrence rate supports the hypothesis that stars that appear magnetically inactive are probably hosts to nearby, highly irradiated exoplanets.
Additionally, the researchers found that the survey was very comprehensive, identifying nearly 95 percent of exoplanets that were more than 10 times more massive than Earth and orbited their host stars in five days or less.
The team also extrapolated their results to our cosmic neighborhood, compiling a list of about 16,000 stars located within 1,600 light-years of the solar system. (For reference, a light year is the distance light travels in a year – about 5.88 trillion miles, or 9.46 trillion kilometers.) From this list, the researchers found 241 stars with similar signatures of low magnetic activity. Given the proportion of exoplanets studied, they estimate that these stars could host around 300 planets, just waiting to be discovered.
Standing is cautiously excited about the potential of the technique. “If confirmed in larger samples, this method could help make exoplanet searches more efficient,” he said.
That’s exactly what the team plans to do, expanding its sample size and continuing to monitor radial velocity data for signs of planets, he added.
Standing, MR, Barnes, JR, Haswell, CA, Stevenson, AT, Faria, JP, Quintin, E., Ross, ZOB, Fossati, L., Jenkins, JS, Alves, D. and Staab, D. (2026) The Dispersed Matter Planet Project sample – detection limits, occurrence rates and new planets, Monthly Notices of the Royal Astronomical Societydeer370. https://doi.org/10.1093/mnras/stag370
