NASA scientists have devised a brand new means to make use of planets that cross, or “transit,” the face of their dad or mum stars to analyze stellar “spottiness.” The new method, known as the “StarryStarryProcess,” may be used to find extra in regards to the atmospheres of planets.
The StarryStarryProcess builds upon the transit technique that has been employed by NASA’s TESS (Transiting Exoplanet Survey Satellite) and now-retired Kepler area telescope missions to detect exoplanets. It might be employed by astronomers to evaluate information from these missions and from NASA’s forthcoming Pandora exoplanet-observing satellite tv for pc.
“Many of the fashions researchers use to research information from exoplanets, or worlds past our solar system, assume that stars are uniformly bright disks,” study team leader Sabina Sagynbayeva, of Stony Brook University in New York, said in a statement. “But we know just by looking at our own sun that stars are more complicated than that. Modeling complexity can be difficult, but our approach gives astronomers an idea of how many spots a star might have, where they are located and how bright or dark they are.”
What do transits inform us?
TESS and Kepler have used the transit method to great effect to discover planets beyond the solar system. In fact, the majority of the over 5,000 worlds in the exoplanet catalog were discovered via the tiny dips in starlight they cause as they cross the face of their parent star.
Tracking how a star’s light changes as a planet moves across its face from our position here on Earth helps build a light curve. Brightness falls slightly as the planet moves in front of the star, with minimum brightness achieved when the exoplanet is fully in front of the star. The brightness then steadily increases as the planet moves past the star, bringing the transit to a close.
In addition to helping discover planets, measuring transits can help determine the distance between a planet and its star, as well as the planet’s size and rough surface temperature. Additionally, because chemicals absorb light at characteristic wavelengths, as starlight passes through the atmosphere of a planet, a process called spectroscopy can be used to determine the chemical composition of that atmosphere.
However, astronomers often find that light curves aren’t as straightforward as they appear. In addition to the drops caused by planetary transits, scientists have spotted dips that are smaller and more complicated. The prevailing theory is that these are the result of “starspots” akin to the sunspots that punctuate the surface of our star, the sun.
The number of sunspots, which are cool and dark patches on the sun, varies across its 11-year solar cycle, with the maximum number of sunspots corresponding with maximum solar activity. They can often be used to predict solar activity and how the solar cycle is progressing.
Therefore, secondary dips in light curves can be used to determine how active the star is, which direction it is tilted, and the angle of the transiting planet’s orbit. The StarryStarryProcess takes this to the next level, revealing even more about these characteristics.
“Knowing more about the star in turn helps us learn even more about the planet, like a feedback loop,” team member Brett Morris, a senior software engineer at the Space Telescope Science Institute in Baltimore, defined in the identical assertion.
“For example, at cool enough temperatures, stars can have water vapor in their atmospheres,” Morris added. “If we want to look for water in the atmospheres of planets around those stars — a key indicator of habitability — we’d better be very sure that we’re not confusing the two.”
To check the StarryStarryProcess, the group appeared on the transits a planet known as TOI 3884 b makes of its dad or mum star, situated round 141 light-years away. The planet is believed to be a gasoline large, round 5 occasions the scale of our planet however with 32 occasions its mass. TOI 3884 b was found in 2022 by TESS.
Using the StarryStarryProcess, the group decided that the dad or mum star of TOI 3884 b has teams of starspots concentrated at its north pole, which is tilted towards Earth. This additionally signifies that TOI 3884 b crosses the poles of its dad or mum star from our perspective because it makes its transits.
At the second, the StarryStarryProcess can solely be utilized in seen gentle, that means it might probably’t be utilized to exoplanet observations made by the James Webb Space Telescope (JWST). However, the Pandora satellite tv for pc, which is predicted to launch later this 12 months, will make its observations in a number of wavelengths of sunshine, that means that scientists could make use of this new mannequin once more as soon as it begins accumulating information.
“The TESS satellite has discovered thousands of planets since it launched in 2018. While Pandora will study about 20 worlds, it will advance our ability to pick out which signals come from stars and which come from planets,” Allison Youngblood, TESS mission scientist at NASA’s Goddard Space Flight Center in Maryland, mentioned within the assertion. “The more we understand the individual parts of a planetary system, the better we understand the whole — and our own.”
The group’s analysis was revealed on Monday (Aug. 25) in The Astrophysical Journal.