How Many Exoplanets Are Out There?

The exact number of planets existing beyond our solar system remains uncertain. Estimates suggest that the Milky Way could host between 100 to 400 billion planets. This figure represents only one of the billions of galaxies scattered across the Universe.

Using Earth-based technology, astronomers have confirmed the existence of 5,084 exoplanets. This number is constantly updated by NASA’s counter for extrasolar worlds. Additionally, there are around 8,800 candidates awaiting confirmation as actual exoplanets.

How Are Exoplanets Detected?

The high number of potential extrasolar planets is largely due to the challenges involved in observing them. Detecting planets orbiting stars other than our Sun is exceptionally difficult, even with today’s advanced technology. The brightness of the parent star typically outshines the light reflected by the planet by thousands of times. Consequently, only about twenty exoplanets have been directly imaged thus far.

One common method of identifying these distant worlds is through indirect detection. When a planet passes in front of a star, it causes a slight dimming effect. If this dimming occurs at regular intervals, it suggests the presence of a planet orbiting the star. Another method involves observing the shifts in light wavelengths caused by the gravitational pull of the exoplanet on the star.

[Photo: NASA, Public domain, via Wikimedia Commons]

Detecting HIP 65426 b

The launch of the Webb Space Telescope in July marks a significant milestone in the quest to discover exoplanets. The telescope's enhanced sensitivity has made it possible to directly photograph an extrasolar planet for the first time.

HIP 65426 b, the exoplanet in question, orbits a main-sequence star at a distance of about 110 astronomical units—one astronomical unit is the distance from Earth to the Sun (1 AU = 1.49597870 x 10¹¹ m). Discovered in 2017 by the European Southern Observatory’s VLT telescope team, it was identified using the SPHERE instrument, which operates in the near-infrared spectrum.

How Webb's Telescope Works

Webb's telescope holds a significant advantage over the four VLT telescopes located in Chile. Positioned 1.5 million kilometers from Earth, it avoids atmospheric interference, allowing for clearer observations. The MIRI science instrument and NIRCam camera were employed to capture images of HIP 65426 b. Both instruments utilize coronographs to obscure the star’s light, enabling direct imaging of the planet. Through these observations, scientists estimate that HIP 65426 b has a mass of 7.1 times that of Jupiter, indicating it is likely a gas giant.

“Obtaining such an image is like discovering a cosmic treasure,” remarked Aarynn Carter, an astronomer at the University of California, Santa Cruz, who analyzed the image. “Initially, I could only see starlight, but after processing the photo, I was able to isolate the planet,” he added.

A Landmark Achievement in Astronomy

The Webb Telescope has proven its capability to capture images with remarkable contrast, exceeding initial expectations. Scientists are optimistic that the telescope will enable the detection of planets with masses as low as one-third that of Jupiter in future photographs.

“This is a pivotal moment not just for the Webb Telescope but for the entire field of astronomy,” stated Sasha Hinkley, a professor of physics and astronomy at the University of Exeter, who led the international team responsible for this groundbreaking discovery. Their findings have been documented in an article published on arXiv.org.

Source: arXiv.org, NASA

Webb's Telescope Captures Einstein's Ring

In a separate groundbreaking observation, the Webb Space Telescope also captured a nearly perfect image of Einstein's ring, showcasing its extraordinary capabilities.

This video provides an overview of how Webb captured its first direct image of an exoplanet, marking a significant milestone in the field of astronomy.

In this video, learn about how the James Webb Telescope achieved the clearest image ever seen in history, providing unprecedented insights into the cosmos.

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