NEOs 2011 UL21 and 2024 MK passing Earth this week

[gary]

Originally Posted by By Elissa Steedman, ABC

Two large asteroids are safely passing Earth this week. They are:

2011 UL21
2024 MK
The occurrence is especially notable for astronomers because 2024 MK was only discovered on June 16.

2011 UL21 was closest to Earth earlier this morning, with a distance of 6,634,279 kilometres.

That's about 17 times further than the Moon, according to the European Space Agency.

This is the asteroid's closest orbit since it was first discovered in October 2011.

Meanwhile, 2024 MK will approach Earth at a distance of about 290,000 kilometres late Saturday.

At that stage, it will be pass nearer to Earth than the Moon.

Headlines have described 2011 UL21 as 'mountain-sized' and a 'planet killer'.

That's because the space rock is 2.3 kilometres wide, which makes it larger than most near-Earth objects.

2024 MK is a fair bit smaller.

Its diameter is believed to be between 122 and 256 metres.

While that sounds quite little in comparison to 2011 UL21, both would have the capacity to do quite a lot of damage if they were ever to strike Earth.


While both will be most visible for Australian stargazers tonight, you won't be able to see them without some help.

A small telescope will be needed to get a good view.

If you don't have one handy, Dr Lance A M Benner at the California Institute of Technology's Jet Propulsion Laboratory suggested binoculars could be enough to spot 2024 MK from areas with dark skies.

You can check where to look for UL21 in the night sky via In-The-Sky.org, an astronomy project run by European Space Agency data scientist Dominic Ford.

Meanwhile, The Sky Live is tracking 2024 MK, so you can find guides on where to look there.

If you miss the asteroids tonight, the Virtual Telescope Project will livestream a visual feed of 2024 MK early Sunday morning.

The team has already run a similar stream, sharing the view of UL21 from the Bellatrix Astronomical Observatory in Ceccano, Italy.

Story here :-
https://www.abc.net.au/news/2024-06-...week/104034960

[EpickCrom (Joe)]

Hi Gary, thanks for this excellent post!

I will try to observe both these NEO's tonight. At around mag 11 they are within reach. Thanks again mate

[Dennis]

On the evening of 28th June 2024 from our back garden in Brisbane, I managed to grab 44 frames of 2024 MK as it sped across our Southern skies. There are a couple of gaps in the trail due to intermittent cloud cover.

I took 44x60 sec exposures (sidereal rate) from 7:09pm to 8:01pm AEST (UT+10).
UTC: 2024-06-28T09:09:00Z to UTC: 2024-06-28T10:01:00Z.

When I processed the frames in Pixinsight and took the result into Photoshop for finishing, I noticed that the trail appeared slightly curved.
Using the Photoshop “Line Tool” I drew a straight line along the trail and sure enough, this reveals a gentle curve to the recorded path of 2024 MK.

A plate solve for the frame recorded at 7:34pm AEST provided the following details.

• Center RA (2000.0): 14h 34m 52.33s
• Center Dec (2000.0): -47° 40' 38.1"
• Scale: 0.6520 arcseconds/pixel
• Size (pixels): 3124 x 2088
• Angular Size: 0° 33' 57" x 0° 22' 41"
• Position Angle: 179° 46' from north through east
• FWHM: 3.72 pixels, 2.43 arcseconds

Later, from 8:04pm to 8:09pm AEST (UTC: 2024-06-28T10:04:00Z to UTC: 2024-06-28T10:09:00Z) I was able to grab 6 frames with the mount locked on NEO 2024 MK and you can see the “stepping” of the star trails when the frames were combined.

Celestron C9.25 Edge HD at F10, ZWO ASI2600MM Pro camera.

Dennis.

[gary]

Originally Posted by Dennis

On the evening of 28th June 2024 from our back garden in Brisbane, I managed to grab 44 frames of 2024 MK as it sped across our Southern skies. There are a couple of gaps in the trail due to intermittent cloud cover.

Hi Dennis,

Fantastic!!!

Best Regards

Gary

[Dennis]

Originally Posted by gary

Hi Dennis,
Fantastic!!!

Best Regards

Gary

Thanks Gary, out of the 10 or 12 NEO’s that I have managed to record as trails, 2024 MK was the first (and only) one to display a curved orbital track in the composite image.

And, as fate would have it, we were clouded out of Saturday night for the closest approach.

Oh well, such is life.

Dennis

[gary]

Originally Posted by Dennis

Thanks Gary, out of the 10 or 12 NEO’s that I have managed to record as trails, 2024 MK was the first (and only) one to display a curved orbital track in the composite image.

And, as fate would have it, we were clouded out of Saturday night for the closest approach.

Oh well, such is life.

Dennis

Hi Dennis,

You taking the time to show the orbital track was curved was brilliant.

I also note that today is the anniversary of the Tunguska event which took
place on 30 Jun 1908.

Two things are worrying about the "near miss" of 2024 MK.

The first is that it was only discovered on 16th June 2024.
Essentially a "zero day" event with regards a deflection probe mission had it
been on a collision path with Earth.

The second was that the initial diameter estimates were between 122 and 256 metres.
Hopefully with the close pass that will be refined.

Nobody knows for certain what the diameter of the Tunguska event object
was but some estimates have it at around 50 metres.

If 2024 MK is a 200 metre diameter NEO and was discovered so late in
the piece, it clearly is a heads-up that the world should invest even
more in early NEO detection.

Some time back NASA had been tasked by the US Congress with detecting
and cataloging 90% of the NEO population of size 140 meters or greater.

You will recollect that the NEO survey Rob McNaught was doing at Siding
Spring was shut down by ANU.

Observatories in the south such as the Vera C. Rubin observatory were
then to take up some of that survey.

NASA is funding the NEO Surveyor spacecraft which is set to launch
in September 2027.

https://www.jpl.nasa.gov/missions/ne...bject-surveyor

[Dennis]

Thanks for the back story, Gary.

Yikes, I had not realized that 2024 MK was such a recent discovery given its size and proximity to Earth, a sobering thought indeed.

Dennis