Near-Earth Asteroid 2012 DA14 - 16 Feb 2013 (Singapore time)

[starfinder]

Am listening to the NASA JPL news conference now. Some interesting facts from the Q&A session answers by the NASA panelists:

- It is not known what material Asteroid 2012 DA14 is made of. Probably it's a rocky silicate asteroid.

- It is therefore also not known what the reflectivity of the asteroid is.

- Hence, the oft-mentioned 45m diameter is just a rough estimate.

- The closest approach point would be somewhere over the region of Indonesia. That's our region too!

- This close approach on 15 Feb would be the closest by this asteroid over the last 100 yrs and the next 100 yrs.

- Impacts on Earth by asteroids of similar size occur on average about once every 1,200 yrs. If this one impacted (which it won't), the force would be around 2.5 megatonnes (equiv. of TNT).

- Impacts by rocky silicate asteroids often don't leave a crater record bec they explode on entry to Earth, such as the 1908 Tunguska event. By contrast, the Meteor Crater in Arizona was caused by an iron-nickel asteroid (which I think was also around 50m in diameter).


Hmmm... no one asked the question I had in mind: i.e. what effect would our Moon's gravitational pull have on the asteroid, and has this been taken into account in the current calculations of the closest approach distance? I was wondering if our Moon might actually pull the asteroid in closer to Earth, or further away. Anyone knows the answer to this?

[Gary]

Nice summary Gavin.

Added this NASA link about the asteroid in first post:
http://www.nasa.gov/topics/solarsystem/ ... flyby.html

There is report about this asteroid in yesterdays Straits Times (9 Feb 2013), page A27 in World section. It is quoting Washington Post and the title is "Building-sized asteroid to pass Earth next week".

The EST to Singapore time conversion of the closest approach was wrongly reported as 1:24am. Should be 3:24am on 16 Feb Singapore time.

[starfinder]

Something interesting. I compared the observing data for Labrador Park and for East Coast Park. There is a difference in the celestial coodinates between the two sites. Below are the generated data for the two sites for 3:32 am (when the asteroid transits the sky some 8 mins after closest approach to Earth).

(Data generated at http://ssd.jpl.nasa.gov/horizons.cgi#top)

** East Coast Park observing site near Carpark C4 and D1 **
JPL/HORIZONS (2012 DA14) 2013-Feb-10 14:34:03
Rec #:728732 (+COV) Soln.date: 2013-Feb-10_01:00:26 # obs: 249 (2012-2013)
Center geodetic : 103.919400,1.30220218,-0.000997 {E-lon(deg),Lat(deg),Alt(km)}
***************************************************************************
Date__(UT)__HR:MN R.A._(ICRF/J2000.0)_DEC Azi_(a-appr)_Elev APmag Illu% Cnst
2013-Feb-15 19:32 t 11 32 40.36 -00 30 14.9 258.8956 80.2740 6.67 94.553 Leo


** Labrador Park **
JPL/HORIZONS (2012 DA14) 2013-Feb-10 14:39:22
Rec #:728732 (+COV) Soln.date: 2013-Feb-10_01:00:26 # obs: 249 (2012-2013)
Center geodetic : 103.805000,1.26222411,-0.000997 {E-lon(deg),Lat(deg),Alt(km)}
***************************************************************************
Date__(UT)__HR:MN R.A._(ICRF/J2000.0)_DEC Azi_(a-appr)_Elev APmag Illu% Cnst
2013-Feb-15 19:32 t 11 32 46.54 -00 29 42.3 259.0182 80.4209 6.67 94.546 Leo


The difference is about 6 seconds in right ascension, and half a minute in declination.
The distance between the two sites is 13.5km (measured with Google Earth); both were set for 2m above sea level.

With such a substantial difference, I think one could conduct parallex measurements within Singapore and derive some useful data about the asteroid's distance and so forth.

Also, it seems that the predicted peak brightness has been revised upwards (brighter) slightly to mag 6.6, from mag 6.9 a week ago.

Another thought: when we view the asteroid near the hours of closest approach, I think we would be seeing it whilst its orbit around the Sun is being changed by the influence of the Earth's gravity (perturbation). It would speed up in much the same way that NASA's probes get a boost from Jupiter etc under the slingshot effect.

[starfinder]

Click here for a celestial map showing the plotted positions for the asteroid, set for the East Coast Park observing site in Singapore:
http://www.heavens-above.com/2012da14.a ... 2&tz=MALST.

I did a comparison and ran the same chart for another location in southeast Asia and it did plot the positions differently. Shows that it takes parallex into account.

[garygoh]

Is there any overrnight observation session for this event ?

[Gary]

Is there any overrnight observation session for this event ?

Hi Gary. Weather permitting, there will be at least 2 - one at ECP, the other at Bishan Park.
Regards, Gary.

[starfinder]

Is there any overrnight observation session for this event ?

Hi Gary. Weather permitting, there will be at least 2 - one at ECP, the other at Bishan Park.
Regards, Gary.

Hi Gary Goh, yup, check out this thread for details of the overnight session at ECP: viewtopic.php?f=5&t=11738

I think you can check out the usual Bishan Park thread for details of that session.

Hope you join one of the sessions!

[orly_andico]

this asteroid is worth $190 billion dollars.

http://www.theregister.co.uk/2013/02/13 ... 2012_da14/

[Gary]

this asteroid is worth $190 billion dollars.

http://www.theregister.co.uk/2013/02/13 ... 2012_da14/

Time to bring out Harry Potter's broom.

[starfinder]

The weather outlook is not looking too promising for tomrw nite!

Hope the clouds don't totally block this asteroid from being viewed by its Earthly admirers in this little red dot.

Oh well, even if we don't get to view it, it was fun reading up on it. But still keep fingers crossed!