Next week’s night sky:
On Monday, December 14, the Geminids meteor shower peaks! This is usually the most spectacular meteor shower in December. Meteor rates can reach up to 120 meteors an hour! Combined with the new moon, this shower should be a terrific finishing point for the astronomy of 2020.
Two young planetary systems
Using NASA’s Transiting Exoplanet Survey Satellite (TESS), astronomers have discovered two new young planetary systems. They found that two stars not older than 320 million years, namely TOI-251 and TOI-942, are orbited by a mini-Neptune planet and two Neptune-sized exoplanets.
TESS is conducting a survey of about 200,000 of the brightest stars near the sun with the aim of searching for transiting exoplanets. So far, it has identified over 2,400 candidate exoplanets (TESS Objects of Interest, or TOI), of which 82 have been confirmed so far.
Summing up the results, the astronomers noted that TOI-251 and TOI-942 are good examples of young planet-hosting field stars that can contribute significantly to characterizing the relationship between planet properties and their ages.
To learn more, go here: https://arxiv.org/abs/2011.13349.
Less water on Mars
Water on Mars, in the form of brines, may not be as widespread as previously thought. Researchers combined data on brine evaporation rates, collected through experiments at the center’s Mars simulation chamber, with a global weather circulation model of the planet to create planetwide maps of where brines are most likely to be found.
Brines are mixtures of water and salts that are more resistant to boiling, freezing and evaporation than pure water. Finding them has implications for where scientists will look for past or present life on Mars and where humans who eventually travel to the planet could look for water.
Favorable conditions for stable brines on the planet’s surface are most likely to be present in mid- to high-northern latitudes, and in large impact craters in the southern hemisphere, he said. In the shallow subsurface, brines might be present near the equator.
In the best-case scenario, brines could be present for up to 12 hours per day. This means that it will be harder to establish a human presence on Mars. To learn more, go here: https://iopscience.iop.org/article/10.3847/PSJ/abbc14.
Something like Planet 9
A planet in an unlikely orbit around a double star 336 light-years away may offer a clue to a mystery much closer to home: A hypothesized, distant body in our solar system dubbed “Planet Nine.”
This is the first time that astronomers have been able to measure the motion of a massive Jupiter-like planet that is orbiting very far away from its host stars and visible debris disk. This disk is similar to our Kuiper Belt of small, icy bodies beyond Neptune. In our own solar system, the suspected Planet Nine would also lie far outside of the Kuiper Belt on a similarly strange orbit. Though the search for a Planet Nine continues, this exoplanet discovery is evidence that such oddball orbits are possible.
This scenario for HD 106906 b’s bizarre orbit is similar in some ways to what may have caused the hypothetical Planet Nine to end up in the outer reaches of our own solar system, well beyond the orbit of the other planets and beyond the Kuiper Belt. Planet Nine could have formed in the inner solar system and been kicked out by interactions with Jupiter. However, Jupiter—the proverbial 800-pound gorilla in our solar system—would very likely have flung Planet Nine far beyond Pluto. Passing stars may have stabilized the orbit of the kicked-out planet by pushing the orbit path away from Jupiter and the other planets in the inner solar system.
Whatever the reason, introspection into this exoplanet will definitely help us understand our own solar system.
To learn more, go here: https://doi.org/10.3847/1538-3881/abc012.
Do you have any cool astronomy research news from this week? Share it in the comments below!