‘Planet confusion’ might sluggish Earth-like exoplanet exploration

When it involves instantly imaging Earth-like exoplanets orbiting faraway stars, seeing is not at all times believing.

A brand new Cornell examine finds that next-generation telescopes used to see exoplanets might confuse Earth-like planets with different sorts of planets in the identical solar system.

With as we speak’s telescopes, dim distant planets are laborious to see towards the glare of their host stars, however next-generation instruments such because the Nancy Grace Roman Space Telescope, at present underneath improvement by NASA, will likely be higher at imaging Earth-like planets, which orbit stars at simply the correct distance to supply prime circumstances for all times.

“Once we have the capability of imaging Earth-like planets, we’re actually going to have to worry about confusing them with completely different types of planets,” stated Dmitry Savransky, affiliate professor within the Sibley School of Mechanical and Aerospace Engineering (College of Engineering) and the Department of Astronomy (College of Arts and Sciences).

“The future telescopes that will enable these observations will be so huge, expensive, and difficult to build and launch that we can’t afford to waste a single second of time on them,” Savransky stated, “which is why it is so important to think through all of these potential issues ahead of time.”

By utilizing Earth’s personal solar system as a mannequin of an unexplored star system, Savransky and Dean Keithly, doctoral pupil within the area of mechanical and aerospace engineering, calculated that even with direct-imaging methods and the elevated capabilities of future, high-powered telescopes, exoplanets as totally different as Uranus and Earth may very well be mistaken for each other.

The analysis was printed Sept. 23 in Astrophysical Journal Letters, and particulars how measurements estimating planet-star separation and brightness may cause “planet confusion.” The modeling finds that when two planets share the identical separation and magnitude alongside their orbits, one planet could be confused for the opposite.

“I’m asking the question, ‘Is it possible that Jupiter could have the same separation and brightness as Earth? Can we possibly confuse these two things that we have just detected?’ And the answer is yes,” Keithly stated. “A habitable Earth-like exoplanet around a star in a different solar system could be confused with many other types of planets.”

Keithly and Savransky—each members of Cornell’s Carl Sagan Institute—recognized 21 instances inside their solar system mannequin through which a person planet had the identical obvious planet-star separation and brightness as one other planet. Using this information, it was calculated that an Earth-like planet may very well be misidentified with a Mercury-like planet in 36% of randomly generated solar methods; with a Mars-like planet in about 43% of randomly generated solar methods; and with a Venus-like planet in additional than 72% of randomly-generated solar methods.

In distinction, confusion between Earth-like planets and bigger gas-giant planets just like Neptune, Saturn and Uranus was much less probably, and will happen in 1-4% of randomly generated solar methods.

Confusing planets for each other could be an costly and time-consuming downside for researchers. Extensive planning and funds go into every use of a high-powered telescope, so the false identification of a liveable exoplanet wastes helpful telescope time. With this downside recognized, researchers can design extra environment friendly exoplanet direct-imaging mission surveys. The researchers warn that additional enhancements to instrument distinction and inner-working angles might exacerbate the issue, and advise that future exoplanet direct-imaging missions make a number of observations to extra precisely differentiate between planets.