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11/05/2019 – Ephemeris – Is the asteroid Hygiea the smallest dwarf planet?

November 5, 2019 Comments off

Ephemeris for Election Day in some places, Tuesday, November 5th. Today the Sun will be up for 10 hours even, setting at 5:26, and it will rise tomorrow at 7:27. The Moon, 1 day past first quarter, will set at 1:12 tomorrow morning.

The asteroid Hygiea is the 4th largest asteroid in the asteroid belt between Mars and Jupiter. After much study with the European Southern Observatory’s Very Large Telescope (VLT) it appears that Hygiea is very nearly spherical. Only the largest asteroid and dwarf planet Ceres is more spherical, and it’s over twice as large. Ceres is 587 miles (945 km) in diameter. Hygiea is 267 miles (430 km) in diameter. By current definition that a body not fitting the definition of planet because it hadn’t cleared it’d orbit of other objects could have the classification of dwarf planet of it was round, or in astronomer-speak has achieved hydrostatic equilibrium. If the International Astronomical Union agrees it would be the smallest dwarf planet.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

SPHERE image of Hygiea

A new SPHERE/VLT image of Hygiea, which could be the Solar System’s smallest dwarf planet yet. As an object in the main asteroid belt, Hygiea satisfies right away three of the four requirements to be classified as a dwarf planet: it orbits around the Sun, it is not a moon and, unlike a planet, it has not cleared the neighbourhood around its orbit. The final requirement is that it have enough mass that its own gravity pulls it into a roughly spherical shape. This is what VLT observations have now revealed about Hygiea.

For more from Universe Today: https://www.universetoday.com/143897/asteroid-hygiea-is-round-enough-that-it-could-qualify-as-a-dwarf-planet-the-smallest-in-the-solar-system/.

09/12/2019 – Ephemeris – NASA and the Europeans plan to deflect an asteroid

September 12, 2019 Comments off

Ephemeris for Thursday, September 12th. Today the Sun will be up for 12 hours and 41 minutes, setting at 7:59, and it will rise tomorrow at 7:19. The Moon, 2 days before full, will set at 6:30 tomorrow morning.

Meeting now in Rome is the AIDA International Conference. It has nothing to do with the opera, but a tortured acronym for Asteroid Impact Deflection Assessment. NASA and the European Space Agency are going to target the satellite of a binary near Earth asteroid Didymos. NASA will supply DART, the impactor, The Italians, a cube sat to fly along and record the impact. Later the Europeans will launch a probe to assess the asteroid deflection. Didymos itself is a half mile in diameter (2560 ft, 780 m), its satellite, a bit more than 500 feet (525 ft, 160 m). The impact should make a marked change in the small body’s orbit of its parent. DART’s launch should come in the summer of 2021 with impact in 2022.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

DART Mission

Schematic of the DART mission shows the impact on the moonlet of asteroid (65803) Didymos. Post-impact observations from Earth-based optical telescopes and planetary radar would, in turn, measure the change in the moonlet’s orbit about the parent body. Credits and caption: NASA/Johns Hopkins Applied Physics Lab.

More information: https://www.universetoday.com/143313/europe-and-us-are-going-to-try-and-deflect-an-asteroid/

https://www.nasa.gov/planetarydefense/dart

11/15/2018 – Ephemeris – Last year’s interstellar visitor was acting funny

November 15, 2018 Comments off

Ephemeris for Thursday, November 15th. The Sun will rise at 7:39. It’ll be up for 9 hours and 34 minutes, setting at 5:14. The Moon, at first quarter today, will set at 12:18 tomorrow morning.

Last year about this time a fast moving asteroid with an odd cigar shape passed through the inner solar system. It’s velocity was such that it didn’t come from around here, meaning our solar system. It was named ‘Oumuamua by its discoverers in Hawai’i. It was spotted as it was heading out, away from the Sun. As it does so, it decelerates as the Sun’s gravitational pull tries to pull it back in. After studying its motion, astronomers noticed that it wasn’t decelerating as fast as it should if it was on a simple ballistic trajectory. Something about it was accelerating it, or causing it to not decelerate as fast as it should. Despite rampant speculation that it’s an interstellar craft on social media ‘Omuamua’s acceleration is well within that possible for comets.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

'Oumuamua
Artist visualization of ‘Oumuamua. Credit: European Southern Observatory / M. Kornmesser
Orbit of 'Oumuamua
Orbit of ‘Oumuamua 1I/2017 U1. Uncredited image from Ars Technica.

10/15/2018 – Ephemeris – The Japanese spacecraft Hayabusa2 is exploring the asteroid Ryugu.

October 15, 2018 Comments off

Ephemeris for Monday, October 15th. The Sun will rise at 7:58. It’ll be up for 11 hours even, setting at 6:58. The Moon, 1 day before first quarter, will set at 11:43 this evening.

The Japanese asteroid sample return mission Hayabusa2 is in the midst of operations at the near-earth asteroid Ryugu. It dropped three rovers that hopped across its surface and later this month will take the first of three samples. Hayabusa means peregrine falcon in Japanese. It will stay at the asteroid until late next year, it then will make a year-long trip back to the Earth, landing in the Outback of Australia. NASA’s own OSIRIS-REx asteroid sample return mission is currently approaching the near-earth asteroid Bennu. It will orbit the asteroid for over a year and can make up to three attempts to take a sample of the asteroid for return to Earth. It is to land at the Utah Test and Training Range in September of 2023.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Hayabusa2 dropping a rover onto Ryugu
An artist’s rendering of Hayabusa2 dropping a rover onto Ryugu. Credit: JAXA/Akihiro Ikeshita.
Ryugu surface
A Hayabusa2 rover captured the surface of Ryugu mid-hop. Credit: JAXA.
OSIRIS-REx at Bennu
Artist’s view of OSIRIS-REx attempting to get a sample from Bennu. Credit: NASA.

11/02/2017 – Ephemeris – Interstellar asteroid discovered passing through the solar system

November 2, 2017 1 comment

Ephemeris for Thursday, November 2nd. The Sun will rise at 8:21. It’ll be up for 10 hours and 7 minutes, setting at 6:29. The Moon, 2 days before full, will set at 7:21 tomorrow morning.

Apparently an interloper has entered the solar system. No, it’s not Nibiru, unless Nibiru is only 525 feet (160 meters) across. It’s name, for now, is A/2017 U1. It’s official name, when it gets one, will be given to this new class of asteroids.. It’s on a hyperbolic trajectory, meaning it won’t be back. We know there are rogue planets, kicked out of their star systems, so why not asteroids and comets? It had an interstellar space velocity relative to the Sun of 15.8 miles per second (25.5 km/s) coming from the direction of the constellation of Lyra. Interestingly that’s the direction the Sun is traveling toward relative to our neighboring stars at nearly the same speed. Maybe it didn’t so much as to run into us, but the Sun and our solar system ran into it!

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

A/2017 U1

Asteroid A/2017 U1 orbit animation. Click to enlarge. Credit NASA/JPL-Caltech.

This body was discovered because it came close to the Earth.  There are probably many of them passing through the solar system  that never come close enough to be found.

Here’s a link: https://www.nasa.gov/feature/jpl/small-asteroid-or-comet-visits-from-beyond-the-solar-system

09/13/2016 – Ephemeris

September 13, 2016 Comments off

Ephemeris for Tuesday, September 13th.  The Sun will rise at 7:19.  It’ll be up for 12 hours and 36 minutes, setting at 7:56.  The Moon, 3 days before full, will set at 4:40 tomorrow morning.

Last Thursday evening an Atlas V rocket lifted off with NASA’s only interplanetary mission this year.  The spacecraft called by one of NASA’s tortured acronyms OSIRIS-Rex is on its way to the asteroid Bennu, which was discovered in 1999, and named by a 3rd grader in a contest.  Bennu is an Egyptian deity resembling a heron and also resembling the spacecraft.  OSIRIS-Rex will take two years to reach the small asteroid, orbit it for two years mapping it in great detail and will approach to retrieve a sample.  It will take 3 years to return the sample to the Earth in 2023.  Bennu is interesting because it contains organic compounds from the origin of the solar system and because of the tiny chance it could hit the Earth in 200 years or so.

Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

OSIRIS-REXx

The OSIRIS-REx spacecraft with its sampler boom extended.

Categories: Asteroid, Equinox, NASA

09/15/15 – Ephemeris – Not another hoax again: This one’s a supposed asteroid collision

September 15, 2015 Comments off

Ephemeris for Tuesday, September 15th.  The Sun will rise at 7:21.  It’ll be up for 12 hours and 32 minutes, setting at 7:53.   The Moon, 2 days past new, will set at 9:02 this evening.

There is a bogus prediction from the Internet that been circulating for a month or so.  I missed it until a couple of days ago because I visit reputable astronomical web sites.  I check near earth asteroids on spaceweather.com, and there is nothing known as of now that’s 22 meters of larger in size that will come within 2 million miles of the Earth this month.  The dead giveaway that this prediction is bogus is the fact that the impact point is specific, near Puerto Rico, but the impact time is vague, between  the 15th and 28th of September.  An object orbiting the Sun, like the Earth travels at 18 and a half miles a second give or take, the asteroid at a comparable velocity, so the impact time would have to be known to the second.  On top of the Earth’s position, it also rotates

Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Here is a link to NASA’s JPL on the subject.

NASA isn’t the only authority on asteroid orbits and positions.  The Minor Planet Center is part of the International Astronomical Union (IAU), and currently operated under a grant from NASA is the clearinghouse for asteroid positions and orbits. Some discoveries and positions  are supplied by amateur astronomers who aren’t beholden to any government, so there isn’t any conspiracy to keep the knowledge from the public.