As of December 19th, 2022, 5,227 extrasolar planets have been confirmed in 3,908 systems, with over 9,000 more awaiting confirmation. While most of these planets are Jupiter- or Neptune-sized gas giants or rocky planets many times the size of Earth (Super-Earths), a statistically significant number have been planets where water makes up a significant part of their mass fraction – aka. “water worlds.” These planets are unlike anything we’ve seen in the Solar System and raise several questions about planet formation in our galaxy.
In a recent study, an international team led by researchers from the University of Montreal’s Institute for Research on Exoplanets (iREx) found evidence of two water worlds in a single planetary system located about 218 light-years away in the constellation Lyra. Based on their densities, the team determined that these exoplanets (Kepler-138c and Kepler-138d) are lighter than rocky “Earth-like” ones but heavier than gas-dominated ones. The discovery was made using data from NASA’s now-retired Spitzer Space Telescope and the venerable Hubble Space Telescope.
Hot Jupiters are giant exoplanets – even more massive than Jupiter – but they orbit closer to their star than Mercury. When they were first discovered, hot Jupiters were considered oddballs, since we don’t have anything like them in our own Solar System. But they appear to be common in our galaxy. As exoplanets go, they are fairly easy to detect, but because we don’t have up-close experience with them, there are still many unknowns.
A new study used archival data from the Hubble and Spitzer space telescopes to study this class of giant gas exoplanets, and undertook one of the largest surveys ever of exoplanet atmospheres. The researchers said they employed high performance computers to analyses the atmospheres of 25 hot Jupiters using data from about 1,000 hours of telescope observations. Their findings, published in the Astrophysical Journal Supplement Series, help to answer several long-standing questions about hot Jupiters.
The Milky Way galaxy is our home, and yet in some ways, it is the least understood galaxy. One of the biggest challenges astronomers have is in understanding its large-scale structure. Because we’re in the midst of it all, mapping our galaxy is a bit like trying to map the size and shape of a wooded park while standing in the middle of it.
Jupiter is notorious for capturing objects that venture too close to the gas giant and its enormous pull of gravity. Asteroids known as Jupiter Trojans are a large group of space rocks that have been snared by the planet, which usually remain in a stable orbit near one of the Jupiter’s Lagrangian points.
But now, the Hubble Space Telescope has spotted a comet near Jupiter’s Trojan asteroid population. This is the first time a comet has been found in this region, and the team of scientists studying the object – named P/2019 LD2 (LD2) – think the unexpected comet is only a temporary visitor.
The discovery of over 4000 planets (4,171 confirmed and counting!) beyond our Solar System has revolutionized the field of astronomy. Unfortunately, one of the downsides of all these discoveries is how it has shaken up theories about how our Solar System formed. In the past, astronomers thought that the eight planets (or nine, or over one hundred, depending on your point of view) formed where they are currently located.
However, the discovery of gas giants that orbit close to their stars (aka. “Hot Jupiters”) has confounded this thinking. But according to a recent NASA-supported study, the recent discovery of a young gas giant could offer clues as to how Jupiter-like planets form and whether or not they migrate. This discovery was made possible thanks to the Spitzer Space Telescope, which continues to reveal things about our Universe even in retirement.
On Jan. 30th, 2020, NASA’s Spitzer Space Telescope was retired after sixteen years of faithful service. As one of the four NASA Great Observatories – alongside Hubble, Chandra, and Compton space telescopes – Spitzer was dedicated to studying the Universe in infrared light. In so doing, it provided new insights into our Universe and enabled the study of objects and phenomena that would otherwise be impossible.
For instance, Spitzer was the first telescope to see light from an exoplanet and made important discoveries about comets, stars, and distant galaxies. It is therefore fitting that mission scientists decided to spend the last five days before the telescope was to be decommissioned capturing breathtaking images of the California Nebula, which were stitched into a mosaic and recently released to the public.
NASA’s Spitzer Space Telescope has reached the end of its life. Its mission was to study objects in the infrared, and it excelled at that since it was launched in 2003. But every mission has an end, and on January 30th 2020, Spitzer shut down.
The Omega Nebula (Messier 17), also known as the Swan Nebula because of its distinct appearance, is one of the most well-known nebulas in our galaxy. Located about 5,500 light-years from Earth in the constellation Sagittarius, this nebula is also one of the brightest and most massive star-forming regions in the Milky Way. Unfortunately, nebulas are very difficult to study because of the way their clouds of dust and gas obscure their interiors.
For this reason, astronomers are forced to examine nebulas in the non-visible wavelength to get a better idea of their makeup. Using the Stratospheric Observatory for Infrared Astronomy (SOFIA), a team of NASA scientists recently observed the Swan Nebula in the infrared wavelength. What they found has revealed a great deal about how this nebula and stellar nursery evolved over time.
Astronomers estimate that in about four billion years, our Sun will exit the main sequence phase of its existence and become a red giant. This will consist of the Sun running out of hydrogen and expanding to several times its current size. This will cause Earth to become uninhabitable since this Red Giant Sun will either blow away Earth’s atmosphere (rendering the surface uninhabitable) or expand to consume Earth entirely.
In a lot of ways, Earth is getting off easy with these predicted scenarios. Other planets, such as WASP-12b, don’t have the luxury of waiting billions of years for their star to reach the end of its lifespan before eating them up. According to a recent study by a team of Princeton-led astrophysicists, this extrasolar planet is spiraling in towards its star and will be consumed in a fiery death just 3 million years from now.