For the first time in history, astronomers have directly spotted a visible light spectrum bouncing off an exoplanet. This discovery could potentially make it easier for astronomers to discover other distant planets going forward.
The scientists spotted the exoplanet – 51 Pegasi b – using the High Accuracy Radial velocity Planet Searcher tool on a 3.6-meter telescope located in the European Southern Observatory in Chile. 51 Pegasi b, which was first discovered in 1995, is not the first exoplanet to be discovered by scientists, as a few others were discovered in 1992 around a pulsar. It is a “hot Jupiter” gas planet that orbits closely around its parent star.
Generally, scientists study the atmosphere of exoplanets by observing the starlight passing through them when planets orbit around their parent star/sun’s faces. But the researchers made use of a new technique that does not rely on planetary alignment, giving it a wider range of applications. “This type of detection technique is of great scientific importance, as it allows us to measure the planet’s real mass and orbital inclination, which is essential to more fully understand the system,” said lead author Jorge Martins of the Instituto de Astrofisica y Ciencias do Espaco and Porto University in Portugal. He added that the technique allows scientists to estimate “albedo” (reflectivity), “which can be used to infer the composition of both the planet’s surface and atmosphere.”
Based on what Martins and his colleagues discovered, 51 Pegasi b is a highly reflective planet that’s slightly larger than Jupiter in terms of diameter, but with approximately half the mass of our solar system’s resident “giant.”