Asteroids, Asteroid Belt, and Dwarf Planets Lindsay Visher EGR 491 A – Telescope Design

Asteroids Described by NASA: Rocky, airless worlds that orbit our sun, but too small to be called planets Debris left over the formation of our solar system As old as 4.6 billion years Current known count: 781,692 asteroids Majority are gathered in the main asteroid belt Located between Mars and Jupiter Can range in size: 33ft to 329 miles Usually irregularly shaped Few have moons Sometimes called “minor planets” Vesta – brightest and second largest object in the asteroid belt Image taken by Nasa’s Dawn spacecraft in 2012 Vesta’s North Pole

Composition of Asteroids 3 main types of composition: C-, S-, and M- C-type: (Chondrite) Most common type Composed of clay, silicate rocks – dark appearance S-type: (Stony) Composed of silicate materials, nickel-iron M-type: (Metallic) Composed of nickel-iron Different Compositions are related to how far from the sun that the asteroid was formed Image: Asteroid Ida and its moon Dactyl; S-type asteroid; the first asteroid found that has its own moon orbiting it Image taken by Galileo spacecraft in 1994 Ida and its moon Dactyl

Asteroid Belt Between Mars and Jupiter Formed when Jupiter’s gravitational pull caused small bodies to collide Location of most known asteroids Contains between 1.1 to 1.9 million asteroids Largest - Ceres Width = 1 km or 0.6 miles Total mass of all the asteroids in the solar system = less than the Moon Same circular orbit that the planets follow Asteroids can also orbit planets – called Trojan Asteroids

Video https://www.youtube.com/watch?v=BKS0yW8dGcQ Give an idea of how many asteroids there are in our solar system And a timeline of how many we've found in the last couple of decades Orange = main belt of asteroids

Observation of Asteroids Can be seen from Earth with a decent telescope Asteroids reflect some light Dimmer than stars and planets In opposition: appear brighter Often “wandering” fast against starry background ~0.5 arcseconds/minute Ecliptic plane Take several images in the course of an hour Can see dot(s) moving Around 150x to 200x magnification Might be able to see dots moving like this one Specific Asteroid – Need to know its specific location Opposition: When an astronomical body is on opposite side of the celestial sphere than the sun Moving quickly = because they are much closer than stars (Need bigger telescope and ~500x see shape of asteroid) Ecliptic plane – easiest to see

Dwarf Planets According to the IAU, "dwarf" planet has 3 criteria: 1,2: Round object with a significant mass that orbits a star 3: Does not clear their orbital path Definition was revised in 2006 Demoted Pluto and elevated Ceres to a Dwarf planet Meaning: - the status of a planet kind of depends on the area surrounding it - Depends on size of the planet relative to the other objects around it Pluto didn’t meet the third criteria – it does not have "gravitational dominance" over other large objects in its vicinity of space

Dwarf Planets in our Solar System Five recognized dwarf planets in our solar system: 1. Ceres 2. Pluto 3. Eris 4. Makemake 5. Haumea All located in the Kuiper Belt, excluding Ceres, which is located in the Asteroid Belt Many more unconfirmed objects that could be classified as dwarf planets As of 2014

Ceres Discovered in 1801 by Guiseppe Piazzi Largest object in the Asteroid Belt Compiles 25% of the asteroid belt's mass Classified as a Dwarf Planet in 2006 Only one in the inner solar system "Embryonic Planet" - did not complete its formation NASA's spacecraft Dawn – actively exploring since 2015 Named after the ancient roman goddess of corn and harvests

Ceres Diameter = 588 miles Angular size = 0.9 arcseconds Located 2.3 AU away from the sun One orbit around the sun = 1682 days or 4.6 Earth years One day on Ceres = 9 hours Mantle is composed of water and ice Said to contain more water than Earth If Earth = size of nickel, Ceres would be the size of a poppy seed Speculated that Ceres has a solid core and a mantle composed of water and ice Contains more water than Earth does

How to Observe Ceres and Other ‘Dwarf’ Planets Apparent Magnitude = +9.3 Magnitude +6.7 in opposition Need at least 10x50 binoculars to view Dwarf planets reflect some light Have the same appearance as stars Appear as a point with amateur scopes Exact locations of dwarf planets are known Point to the general region of the known dwarf planet Compare with a good star chart Can identify points in the sky that don’t appear on the chart  Dwarf planets Magnitude 6.7 = will just be able to see with the naked eye

Provided by Dr. Lulay Path of Ceres in June of next year

References: https://www.jpl.nasa.gov/infographics/infographic.view.php?id=11268 http://lasp.colorado.edu/education/outerplanets/kbos_dwarfplanets.php https://www.quora.com/What-are-the-similarities-and-differences-between-planets-and-dwarf-planets https://solarsystem.nasa.gov/planets/dwarf-planets/ceres/in-depth/ https://www.space.com/24368-dwarf-planet-ceres-photos-largest-asteroid.html https://simotron.wordpress.com/2012/09/10/ceres-a-dwarf-planet-in-our-solar-system/ https://unofficialnetworks.com/2015/08/11/mountain-bigger-than-denali-discovered-on-dwarf-planet-ceres/ https://solarsystem.nasa.gov/small-bodies/asteroids/in-depth/ https://solarsystem.nasa.gov/small-bodies/asteroids/243-ida/in-depth/ https://www.spacetelescope.org/images/heic1715c/ https://www.spacetv.net/asteroids/ https://lco.global/education/article/background-asteroids-comets-and-neos/

References https://www.spacetv.net/asteroids/ https://socratic.org/questions/what-are-some-non-major-dwarf-planets https://www.space.com/15216-dwarf-planets-facts-solar-system-sdcmp.html https://spaceguardcentre.com/what-are-neos/finding-and-observing-asteroids/ https://www.skyandtelescope.com/observing/see-asteroid-florence-fly-by-earth-this-week/ https://www.skyandtelescope.com/observing/celestial-objects-to-watch/hunting-asteroids- from-your-backyard/ https://www.skyandtelescope.com/observing/vesta-2018-opposition/ https://www.space.com/12969-giant-asteroid-ceres-telescopes-skywatching.html https://www.astroleague.org/al/obsclubs/asteroid/astrcobs.html

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