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‘Planet confusion’ could slow Earth-like exoplanet exploration

Date:
September 30, 2021
Source:
Cornell University
Summary:
A new study finds that next-generation telescopes used to see exoplanets could confuse Earth-like planets with other types of planets in the same solar system.
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When it comes to directly imaging Earth-like exoplanets orbiting faraway stars, seeing isn't always believing. A new Cornell University study finds that next-generation telescopes used to see exoplanets could confuse Earth-like planets with other types of planets in the same solar system.

With today's telescopes, dim distant planets are hard to see against the glare of their host stars, but next-generation tools such as the Nancy Grace Roman Space Telescope, currently under development by NASA, will be better at imaging Earth-like planets, which orbit stars at just the right distance to offer prime conditions for life.

"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," said Dmitry Savransky, associate professor of mechanical and aerospace engineering and of astronomy.

"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 said, "which is why it is so important to think through all of these potential issues ahead of time."

By using Earth's own solar system as a model of an unexplored star system, Savransky and doctoral student Dean Keithly, calculated that even with direct-imaging techniques and the increased capabilities of future, high-powered telescopes, exoplanets as different as Uranus and Earth could be mistaken for one another.

The research details how measurements estimating planet-star separation and brightness can cause "planet confusion." The modeling finds that when two planets share the same separation and magnitude along their orbits, one planet can be confused for the other.

Keithly and Savransky identified 21 cases within their solar system model in which an individual planet had the same apparent planet-star separation and brightness as another planet. Using this data, it was calculated that an Earth-like planet could be misidentified with a Mercury-like planet in 36% of randomly generated solar systems; with a Mars-like planet in about 43% of randomly generated solar systems; and with a Venus-like planet in more than 72% of randomly generated solar systems.

In contrast, confusion between Earth-like planets and larger gas-giant planets similar to Neptune, Saturn and Uranus was less likely, and could occur in 1-4% of randomly generated solar systems.

Confusing planets for one another can be an expensive and time-consuming problem for scientists. Extensive planning and funds go into each use of a high-powered telescope, so the false identification of a habitable exoplanet wastes valuable telescope time. With this problem identified, researchers can design more efficient exoplanet direct-imaging mission surveys.

The researchers warn that further improvements to instrument contrast and inner-working angles could exacerbate the problem and advise that future exoplanet direct-imaging missions make multiple observations to more accurately differentiate between planets.


Story Source:

Materials provided by Cornell University. Original written by Erin Philipson. Note: Content may be edited for style and length.


Journal Reference:

  1. Dean Robert Keithly, Dmitry Savransky. The Solar System as an Exosystem: Planet Confusion. The Astrophysical Journal Letters, 2021; 919 (1): L11 DOI: 10.3847/2041-8213/ac20cf

Cite This Page:

Cornell University. "‘Planet confusion’ could slow Earth-like exoplanet exploration." ScienceDaily. ScienceDaily, 30 September 2021. <www.sciencedaily.com/releases/2021/09/210930134800.htm>.
Cornell University. (2021, September 30). ‘Planet confusion’ could slow Earth-like exoplanet exploration. ScienceDaily. Retrieved March 28, 2024 from www.sciencedaily.com/releases/2021/09/210930134800.htm
Cornell University. "‘Planet confusion’ could slow Earth-like exoplanet exploration." ScienceDaily. www.sciencedaily.com/releases/2021/09/210930134800.htm (accessed March 28, 2024).

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