* Astronomy

Members Login
Post Info
TOPIC: (136108) 2003EL61


L

Posts: 131039
Date:
RE: (136108) 2003EL61
Permalink  
 


An unusual dwarf planet discovered in the outer Solar System could be en route to becoming the brightest comet ever known.
2003 EL61 is a large, dense, rugby-ball-shaped hunk of rock with a fast rotation rate.
Professor Mike Brown has calculated that the object could be due a close encounter with the planet Neptune.
If so, Neptune's gravity could catapult it into the inner Solar System as a short-period comet.

"If you came back in two million years, EL61 could well be a comet...When it becomes a comet, it will be the brightest we will ever see" -  Professor Brown, from the California Institute of Technology (Caltech) in Pasadena.

Read more

__________________


L

Posts: 131039
Date:
Rudolph and Blitzen
Permalink  
 


S/2005 (136108) 1
S/2005 (2003 EL61) 1 (provisional designation; nicknamed "Rudolph" by the Caltech team), renamed S/2005 (136108) 1 once its primary was numbered, was the first satellite discovered around (136108) 2003 EL61. It orbits once every 49.12 0.03 days with semimajor axis 49,500 400 km and eccentricity 0.050 0.003. Mutual occultations of the moon and the primary, as seen from Earth, occurred in 1999 and will not occur again until 2138.
Only the total mass of the system is known, but assuming the moon has the same density and albedo as the primary, the mass of the satellite is 1% of the mass of (136108) 2003 EL61 and it has a diameter of ~310 km.


S/2005 (136108) 2
S/2005 (2003 EL61) 2 (provisional designation), later renamed S/2005 (136108) 2, is the smaller inner satellite of (136108) 2003 EL61. The object has been nicknamed "Blitzen".

Its discovery was announced on November 29, 2005. It was found 39,300 km away and, with the assumption of a circular orbit, it orbits the primary in 34.1 0.1 days, and is inclined 39 6 from the larger moon.
The measured brightness implies a diameter 12% that of (136108) 2003 EL61, ~170 km, assuming similar albedo.

Source

__________________


L

Posts: 131039
Date:
RE: New solar object
Permalink  
 


Date    TT    R. A. (2000) Decl.     Delta      r     Elong.  Phase     V
2006 11 01 13 31.83 +18 59.5 51.989 51.186 35.7 0.6 17.4
2006 11 06 13 32.24 +18 58.4 51.952 51.186 39.0 0.7 17.4
2006 11 11 13 32.63 +18 57.5 51.910 51.185 42.6 0.8 17.5
2006 11 16 13 33.02 +18 56.9 51.861 51.184 46.4 0.8 17.5
2006 11 21 13 33.39 +18 56.6 51.808 51.184 50.4 0.9 17.5
2006 11 26 13 33.75 +18 56.5 51.750 51.183 54.5 0.9 17.5
2006 12 01 13 34.08 +18 56.8 51.688 51.183 58.7 0.9 17.5
2006 12 06 13 34.39 +18 57.3 51.621 51.182 63.0 1.0 17.5
2006 12 11 13 34.68 +18 58.1 51.552 51.181 67.4 1.0 17.5
2006 12 16 13 34.95 +18 59.2 51.479 51.181 71.8 1.0 17.5
2006 12 21 13 35.18 +19 00.6 51.405 51.180 76.3 1.1 17.5
2006 12 26 13 35.39 +19 02.2 51.328 51.179 80.8 1.1 17.5
2006 12 31 13 35.56 +19 04.1 51.250 51.179 85.3 1.1 17.5
2007 01 05 13 35.71 +19 06.2 51.172 51.178 89.8 1.1 17.5
2007 01 10 13 35.82 +19 08.5 51.094 51.178 94.3 1.1 17.5
2007 01 15 13 35.90 +19 11.0 51.016 51.177 98.9 1.1 17.4
2007 01 20 13 35.94 +19 13.7 50.940 51.176 103.4 1.1 17.4
2007 01 25 13 35.95 +19 16.6 50.865 51.176 107.9 1.0 17.4
2007 01 30 13 35.93 +19 19.6 50.793 51.175 112.3 1.0 17.4
2007 02 04 13 35.87 +19 22.7 50.723 51.174 116.7 1.0 17.4
2007 02 09 13 35.78 +19 25.9 50.657 51.174 121.1 0.9 17.4
2007 02 14 13 35.67 +19 29.1 50.596 51.173 125.4 0.9 17.4
2007 02 19 13 35.52 +19 32.3 50.538 51.173 129.5 0.9 17.4
2007 02 24 13 35.34 +19 35.6 50.485 51.172 133.5 0.8 17.4
2007 03 01 13 35.13 +19 38.8 50.438 51.171 137.4 0.8 17.4
2007 03 06 13 34.90 +19 42.0 50.396 51.171 141.0 0.7 17.4
2007 03 11 13 34.65 +19 45.1 50.361 51.170 144.3 0.6 17.4
2007 03 16 13 34.38 +19 48.1 50.331 51.169 147.2 0.6 17.4
2007 03 21 13 34.09 +19 50.9 50.308 51.169 149.5 0.6 17.4
2007 03 26 13 33.78 +19 53.6 50.291 51.168 151.3 0.5 17.4
2007 03 31 13 33.46 +19 56.1 50.281 51.168 152.3 0.5 17.4
2007 04 05 13 33.14 +19 58.4 50.278 51.167 152.5 0.5 17.4
2007 04 10 13 32.81 +20 00.5 50.281 51.166 151.9 0.5 17.4
2007 04 15 13 32.47 +20 02.4 50.291 51.166 150.4 0.6 17.4
2007 04 20 13 32.13 +20 04.0 50.307 51.165 148.4 0.6 17.4
2007 04 25 13 31.80 +20 05.3 50.330 51.164 145.8 0.6 17.4
2007 04 30 13 31.47 +20 06.4 50.359 51.164 142.7 0.7 17.4


__________________


L

Posts: 131039
Date:
2003 EL61
Permalink  
 


With the controversy over the classification of Eris, Pluto, and "dwarf planets," a lesser known Kuiper Belt object (KBO) is vying to be the most interesting solar system object beyond Neptune. Soon after they found it, astronomers learned that 2003 EL61 is shockingly strange. Its spin period, just 3.9 hours, makes it the fastest rotating known body in our solar system larger than 100 kilometres across. Its shape is even weirder it looks like a squashed American football, and at its widest point the highly elongated body likely exceeds even Eris's diameter. Astronomers also found two moons of it: an inner one with a 35-day non-circular orbit, and a brighter one in a 49-day circular orbit. Moreover, the object's density and rapid rotation imply that it is solid rock, with only the thinnest of icy veneers coating its surface.

Read more

__________________


L

Posts: 131039
Date:
(136108) 2003 EL61 Ephemeris
Permalink  
 


Date       UT      R.A. (J2000) Decl.    Delta     r     El.    Ph.   V 
2006 09 25 000000 13 28 45.1 +19 15 30 52.071 51.191 28.4 0.5 17.4
2006 09 26 000000 13 28 49.8 +19 14 55 52.073 51.191 28.1 0.5 17.4
2006 09 27 000000 13 28 54.6 +19 14 21 52.075 51.190 27.8 0.5 17.4
2006 09 28 000000 13 28 59.4 +19 13 48 52.077 51.190 27.5 0.5 17.4
2006 09 29 000000 13 29 04.2 +19 13 14 52.079 51.190 27.3 0.5 17.4
2006 09 30 000000 13 29 09.1 +19 12 42 52.080 51.190 27.0 0.5 17.4
2006 10 01 000000 13 29 14.0 +19 12 09 52.081 51.190 26.9 0.5 17.4
2006 10 02 000000 13 29 18.9 +19 11 37 52.082 51.190 26.7 0.5 17.4
2006 10 03 000000 13 29 23.8 +19 11 06 52.083 51.190 26.6 0.5 17.4
2006 10 04 000000 13 29 28.7 +19 10 35 52.083 51.190 26.5 0.5 17.4
2006 10 05 000000 13 29 33.7 +19 10 04 52.083 51.189 26.4 0.5 17.4
2006 10 06 000000 13 29 38.6 +19 09 34 52.083 51.189 26.4 0.5 17.4
2006 10 07 000000 13 29 43.6 +19 09 04 52.083 51.189 26.4 0.5 17.4
2006 10 08 000000 13 29 48.6 +19 08 35 52.082 51.189 26.4 0.5 17.4
2006 10 09 000000 13 29 53.6 +19 08 06 52.081 51.189 26.5 0.5 17.4
2006 10 10 000000 13 29 58.7 +19 07 38 52.080 51.189 26.6 0.5 17.4
2006 10 11 000000 13 30 03.7 +19 07 10 52.078 51.189 26.7 0.5 17.4
2006 10 12 000000 13 30 08.7 +19 06 43 52.077 51.189 26.9 0.5 17.4
2006 10 13 000000 13 30 13.8 +19 06 16 52.075 51.189 27.1 0.5 17.4
2006 10 14 000000 13 30 18.8 +19 05 50 52.073 51.188 27.3 0.5 17.4
2006 10 15 000000 13 30 23.9 +19 05 24 52.070 51.188 27.6 0.5 17.4


__________________


L

Posts: 131039
Date:
2003EL61
Permalink  
 


Title: The Surface of 2003EL61 in the Near Infrared
Authors: C. A. Trujillo, M. E. Brown, K. M. Barkume, E. L. Schaller, D. L. Rabinowitz
Date: 26 Jan 2006

Researchers report the detection of crystalline water ice on the surface of 2003EL61.
Reflectance spectra were collected from Gemini North telescope from 1.0 to 2.4 micron wavelength range, and from the Keck telescope across the 1.4 to 2.4 micron wavelength range. The signature of crystalline water ice is clear and obvious in all data collected. Like the surface of many outer solar system bodies, the surface of 2003EL61 is rich in crystalline water ice, which is energetically less favoured than amorphous water ice at cold temperatures, suggesting resurfacing processes may be taking place.
The near infrared colour of the object is much bluer than a pure water ice model. Adding a near infrared blue component such as hydrogen cyanide or phyllosilicate clays improves the fit considerably, with hydrogen cyanide providing the greatest improvement.
The addition of hydrated tholins and bitumens also improves the fit but is inconsistent with the neutral V-J reflectance of 2003EL61. A small decrease in reflectance beyond 2.3 micron may be attributable to cyanide salts.
Overall, the reflected light from 2003 EL61 is best fit by a model of 2/3 to 4/5 pure crystalline water ice and 1/3 to 1/5 near infrared blue component such as hydrogen cyanide or kaolinite. The surface of 2003 EL61 is unlikely to be covered by significant amounts of dark material such as carbon black, as their pure ice models reproduce published albedo estimates derived from the spin state of 2003 EL61.

Relative reflectance spectrum of 2003 EL61 from Gemini and Keck (black filled circles and xs) normalised to the model. Overplotted is their best fit 100% pure crystalline water ice model with kaolinite clay at its true geometric albedo.
The dotted line is the water ice component and the solid gray line is the spectrum of kaolinite alone, shifted upwards by 0.1 for clarity.



Read more (345kb, PDF)

-- Edited by Blobrana at 07:54, 2006-05-08

__________________


L

Posts: 131039
Date:
Permalink  
 

Researchers believe the new moons coalesced from debris after another large KBO smashed into 2003 EL61 when the solar system was forming, more than 4 billion years ago. In their scenario, the crash heated 2003 EL61 so much that it lost most of its ice and was left as mostly rock. It also set the hot rock spinning so fast it got stretched into its cigar shape before cooling.

This may explain a few of the system's features. But the "tough question" is why the two tiny moons are in such different orbital planes.

"My best guess is that when both moons were closer, they gravitationally interacted and moved...My guess is that while many objects underwent collisions, only the most massive ones retained a disc of material out of which moons could coalesce" - Mike Brown, Caltech in Pasadena

__________________


L

Posts: 131039
Date:
RE: New solar object
Permalink  
 




Observations reveal a double-peaked rotational light curve with period of 3.9154 0.0002 hours and peak to peak amplitude of about 0.28 0.04 magnitudes.
The double peaks indicate an elongated object with large to small axis ratio of 1.4.
Observations also reveal a total length of 1960 - 2500 km, a mean density of 2600 - 3340 kg m-3, and a visual albedo greater than 0.6.
They also measured a neutral reflectance at visible wavelengths and a linear phase curve with slope varying from 0.09 mag deg-1 in the B band to 0.13 mag deg-1 in the I band.
The absolute V-band magnitude is 0.259 0.028.

Observations made during 5 commissioning nights between 26 January and 30 June 2005 allow the researchers to derive the following orbital solution for the delta K=3.8 magnitude satellite with respect to the primary:

a=49100400 km
P=49.050.03 days
e=0.0480.002.

This implies a total mass of the system of 3.90.1 x 1021 kg, or 30.20.8% the mass of Pluto.

WebLink:


__________________


L

Posts: 131039
Date:
2003EL61
Permalink  
 


Mike Brown has reported the discovery of a second satellite around 2003 EL61:

The first moon to 2003 EL61 was discovered on January 28th 2005 by observations at the Keck Observatory, the second satellite is fainter than the first, but still detected in three of the five images of the first satellite.


Credit Mike Brown

The orbits of the two satellites are seen almost edge on, which is why they look so elongated. The orbits are tilted to each other by about 40 degrees.



Both satellites appear to be quite small. The larger one is perhaps 1% of the mass of the primary while the smaller is only 0.2% of the mass of the primary.
The new satellite appears to circle 2003 EL61 once every 34 days.


Image of the new moons (above left and directly below).


Two faint point sources are seen near 2003 EL61 on the image from the night of 2005 June 30, the night with the highest quality image correction.
The brighter source is the well-characterized satellite discovered by Brown et al. (2005a). The second source appears in each individual frame and is stationary to a measurement error of 4 pixels with respect to the KBO over 5 separate observations spaced by a total of 5 minutes.
A background star would have moved by 10 pixels during this time period. A faint source is also clearly seen in the full coadded observations of 2005 March 3. The source is too faint to be seen in individual exposures, but in two stacks of four 30 second exposures taken 6.8 minutes apart the source is also stationary to a measurement error of 4 pixels. A background star would have moved 25 pixels between these two observations.
Both of these sources are consistent with a relative brightness of 1:5 0:5% the brightness of the primary. In the 2005 Mar 04 image a source consistent with this brightness is seen 0.3 arc seconds from the primary. The source remains stationary over a time period when a background star should have moved 23 pixels. At this small separation from the primary, PSF artefacts are possible, though no artefacts of this brightness are seen in any of the other LGS AO images, so we tentatively consider the detection real.
A source this faint would not have been detected in the lower quality 2005 Jan 26 image, but would have been seen at a separation greater than 0.4 arc seconds in the 2005 Mar 01 image.


Read More (PDF)

First moon:
V magnitude 17.5
FWHM (arcseconds) 0.063
Strehl ratio 0.18
Satellite fractional brightness 5:9 0:5%
Apparent semi-major axis (arcsec) 1.3
True semi-major axis (km) 49500


Second moon:

V magnitude 17.5
FWHM (arcseconds) 0.063
Strehl ratio 0.18
Satellite fractional brightness 1:5 0:5
Apparent semi-major axis (arcsec) 1.0c
True semi-major axis (km) 39300c
Orbital period (days) 34.1c

__________________


L

Posts: 131039
Date:
Santa
Permalink  
 




__________________
«First  <  1 2 3 4 5 6 7  >  Last»  | Page of 7  sorted by
Quick Reply

Please log in to post quick replies.



Create your own FREE Forum
Report Abuse
Powered by ActiveBoard