Astro Blog

https://www.nytimes.com/2023/02/08/science/quaoar-rings-roche-limit.html By Kenneth Chang , The New York Times.  Excerpt: Quaoar, which orbits the sun in the distant Kuiper belt, is the latest small object shown to have a ring like the ones around Saturn. ...Quaoar (pronounced KWA-wahr ...is a little less than half the diameter of Pluto and about a third of the diameter of Earth’s moon. It is likely to be big enough to  qualify as a dwarf planet , pulled by its gravity into a round shape. ...The ring is not visible in telescope images. Rather, astronomers found it indirectly, when distant stars happened to pass behind Quaoar, blocking the starlight. From 2018 through 2021, Quaoar passed in front of four stars, and astronomers on Earth were able to observe the shadow of the eclipses, also known as stellar occultations. However, they also observed some dimming of the starlight before and after the star blinked out. That pointed to a ring obscuring part of the light, an inte...

https://eos.org/articles/meet-hygiea-the-smallest-dwarf-planet-in-our-solar-system Source:   By Javier Barbuzano, Eos/AGU. Excerpt: Around 2 billion years ago, two large rock bodies hit each other in the main asteroid belt, a region between the orbits of Mars and Jupiter populated by fragments of rocks of various sizes. The impactor, with a size ranging from 75 to 150 kilometers in diameter, hit a body at least 4 times larger. Astronomers have known about this impact for a long time because it created a whole family of asteroids in the main asteroid belt, formed by the celestial body Hygiea and almost 7,000 smaller asteroids that have similar orbits. Hygiea itself has been considered an asteroid since it was discovered in 1849 by Italian astronomer Annibale de Gasparis. With a diameter just over 430 kilometers, it is the fourth-largest object in the main asteroid belt. New observations obtained with the Very Large Telescope (VLT), located in Chile and operated by the European ...

Source:   By JoAnna Wendel   Earth & Space News EoS (AGU) Excerpt: 1. Dwarf Planets Are as Complex as Regular Planets. ...2. Dwarf Planets Reveal Neptune’s Orbital Origins. ...3. Dwarf Planets Give Us a Peek into the Early Solar System. ...4. Dwarf Planet Candidates Helped Scientists “Find” Planet 9. ...5. Ceres (We Hope) Will Help Us Understand Icy Ocean Moons. ...6. Dwarf Planets Are Prolific.... https://eos.org/articles/six-things-dwarf-planets-have-taught-us-about-the-solar-system

Source:   By Ron Cowen, EoS, Earth & Space Science News, AGU Excerpt: ...The presence of ammonia-rich clay on much of the surface of Ceres suggests that this dwarf planet—the largest object in the asteroid belt—may have formed far out in the solar system, then wandered in.... https://eos.org/articles/the-dwarf-planet-that-came-in-from-the-cold-maybe

Source:   NASA Release 15-149 NASA’s New Horizons spacecraft is at Pluto. After a decade-long journey through our solar system, New Horizons made its closest approach to Pluto Tuesday, about 7,750 miles above the surface -- roughly the same distance from New York to Mumbai, India – making it the first-ever space mission to explore a world so far from Earth. [photo taken on July 13, 2015 when the spacecraft was 476,000 miles (768,000 kilometers) from the surface. ...the last and most detailed image sent to Earth before the spacecraft’s closest approach to Pluto on July 14.] http://www.nasa.gov/press-release/nasas-three-billion-mile-journey-to-pluto-reaches-historic-encounter

Source:   NASA RELEASE 15-034. Excerpt: NASA's Dawn spacecraft has become the first mission to achieve orbit around a dwarf planet. The spacecraft was approximately 38,000 miles (61,000 kilometers) from Ceres when it was captured by the dwarf planet’s gravity at about 4:39 a.m. PST (7:39 a.m. EST) Friday. ..."Since its discovery in 1801, Ceres was known as a planet, then an asteroid and later a dwarf planet," said Marc Rayman, Dawn chief engineer and mission director at JPL. "Now, after a journey of 3.1 billion miles (4.9 billion kilometers) and 7.5 years, Dawn calls Ceres, home.".... See also New York Times photos . http://www.nasa.gov/press/2015/march/nasa-spacecraft-becomes-first-to-orbit-a-dwarf-planet/#.VPy7UmZIfZE

Source:   Dauna Coulter, Science@NASA Excerpt: At this very moment one of the fastest spacecraft ever launched -- NASA's New Horizons -- is hurtling through the void at nearly one million miles per day. ... headed for the lonely world of Pluto on the outer edge of the solar system. Although astronomers now call Pluto a dwarf planet, "it's actually a large place, about 5,000 miles around at the equator," says Alan Stern, principal investigator for the mission. "And it's never been explored."  science.nasa.gov/science-news/science-at-nasa/2011/02sep_newhorizons/