2004 QP

main belt asteroid discovered from La Cañada

2004.08.15

 

 

One of the stacked frames used for blinking in astrometrica (1). When I was working this field only three asteroids where plotted on the screen by the program. After the catalog update by the minor planet center, up to five asteroids are shown. The new asteroid, on the center left, is marked with two lines. Another three asteroids are visible in the image, the fourth one, next to and just below the discovery, was at magnitud > 21, beyond the reach of the telescope. A satellite trail can be seen crossing the image.

 

 

 

On follow up observations of 2004 PP75 requested by Michel Ory the night of 2004 August the 15th I was unable to find it but considering it was just a Väisälä orbit I thought it could be in a nearby field. I moved the telescope a little to the east and started a new series of pictures, after one hour integration time some tiny objects started showing up in the blink window, some of them were identified with known  objects while one of them remained unidentified.

 

I thought it could be a new object and I logged into the minor planet center mpchecker online service to check for possible candidates around the area but nothing was there about, moving in a similar manner.

 

Then I sent my astrometry to the center, after a while I got an e-mail from Gareth Williams stating that one of the objects that I sent,  as identified with a known asteroid, didn’t fit well,  this could be another new one I thought, then I resent the astrometry for this object as unidentified.

 

The weather was overcasting and I needed more observations, I talked to Rafael Ferrando from observatory Pla d’Arguines (941), he is a very experienced observer and has done many asteroid discoveries (65 by now) , Rafael told me he would try it that same night if at all possible. I also requested follow up to Peter Birtwhistle, running the Great Shefford Observatory (J95) and to Michel Ory.

 

Rafael Ferrando detected both candidates just before the clouds covered the scene, he sent the astrometry to the mpc, with a big note to make clear that in the case of  discovery credit should be given to La Cañada, thanks very much indeed Rafa.

 

The next day the mpc published the daily orbit update I saw that the observations of my first candidate have been linked to an existing object 2001 YS106, it was quite a surprise because it didn’t appear on the minor planet checker service. The other object however, the one I thought was already catalogued and that Gareth told me it didn’t fit well, was not linked yet.

 

I sent an e-mail to Tim Spahr at the mpc asking for some clues, he told me that my provisional designation was wrong ‘cause it was longer than six chars, I resent the astrometry under a new, shorter, designation.

 

The next night Rafael Ferrando was very kind to try it again. The mpc computed the elements of the orbit and was published on the daily orbit update of 19.08.2004 with the designation 2004QP.

 

On 2004 August the 20th I received and e-mail from Peter with astrometry he did on both objects, this will expand the observed arc to produce more accurate orbital elements before the new object goes beyond the limits of our telescopes.

 

This tiny body has an absolute magnitude H=19.7, the derived size is in the 300-600 m range.

 

Unfortunately, according to the Lowell Observatory online services, the object is so faint that it will keep below mag 22 for many years on, unless some big telescope catches it again in a few days time it will be lost.

 

Here follows the first orbit computed by Ramon Naves with project Pluto’s FindOrb based only on my first observations, it is apparent that these elements are for a main belt asteroid.

 

Orbital elements:
C40815A
   Perihelion 2004 Aug 16.040392 TT
Epoch 2004 Aug  3.0 TT = JDT 2453220.5
M 355.96153              (2000.0)            P               Q
n   0.30968913     Peri.   32.37542      0.83407635      0.55140639     
a   2.1636419      Node   294.15251     -0.50987005      0.75924827     
e   0.2138255      Incl.    1.02726     -0.21059237      0.34567765     
P   3.18           H   19.9           G   0.15      q 1.7010000
From 6 observations 2004 Aug. 16-16;   RMS error 1.041 arcseconds

 

Below is the first orbit from the minor planet center,

2004 QP 

Epoch 2004 Aug. 3.0 TT = JDT 2453220.5                  MPC
M 359.72685              (2000.0)            P               Q
n   0.28232794     Peri.   24.65060     +0.78002928     +0.62547360
a   2.3012659      Node   296.61986     -0.57746142     +0.70823154
e   0.2219780      Incl.    1.17677     -0.24102412     +0.32740015
P   3.49           H   19.7           G   0.15
From 21 observations 2004 Aug. 16-18.
  
Residuals
20040816 *J87  0.1-  0.1-    20040817  941  0.4-  0.1-    20040818  941  0.1+  0.2-
20040816  J87  0.1+  0.1-    20040817  941  0.1-  0.1-    20040818  941  0.2-  0.1-
20040816  J87  0.5-  1.3+    20040817  941  0.1-  0.1+    20040818  941  0.1-  0.0+
20040816  J87  0.5+  1.9-    20040817  941  0.1+  0.0     20040818  941  0.1+  0.1+
20040816  J87  0.4-  0.7+    20040817  941  0.1+  0.5+    20040818  941  0.0-  0.1-
20040816  J87  0.2+  0.1+    20040817  941  0.1-  0.5+    20040818  941  0.1+  0.1-
20040816  J87  0.4+  1.1-    20040817  941  0.0+  0.6+    20040818  941  0.1+  0.1-

 

After some more observations were added the orbit doesn’t change much,

2004 QP

Display all designations for this object 

Epoch 2004 Aug. 3.0 TT = JDT 2453220.5                  MPC
M 356.23508              (2000.0)            P               Q
n   0.26451822     Peri.   29.46451     +0.84278513     +0.53788466
a   2.4034347      Node   297.98256     -0.49812492     +0.76546847
e   0.2215925      Incl.    1.28684     -0.20392346     +0.35318283
P   3.73           H   19.4           G   0.15
From 28 observations 2004 Aug. 16-20.
  
Residuals
20040816 *J87  0.2+  0.2-    20040817  941  0.0+  0.1+    20040818  941  0.2+  0.1+
20040816  J87  0.4+  0.2-    20040817  941  0.0+  0.6+    20040820  J95  1.0+  0.8+
20040816  J87  0.3-  1.2+    20040817  941  0.2-  0.6+    20040820  J95  0.1-  1.4-
20040816  J87  0.7+  2.0-    20040817  941  0.1-  0.8+    20040820  J95  0.7-  3.0-
20040816  J87  0.5-  0.6+    20040818  941  0.2+  0.1+    20040820  J87  0.7-  0.6+
20040816  J87  0.0+  0.1+    20040818  941  0.1-  0.1+    20040820  J87  2.6-  0.9+
20040816  J87  0.1+  1.1-    20040818  941  0.0+  0.3+    20040820  J87  1.8+  0.3+
20040817  941  0.4-  0.1+    20040818  941  0.2+  0.3+    20040820  J87  1.1+  0.1+
20040817  941  0.2-  0.0+    20040818  941  0.1+  0.1+
20040817  941  0.2-  0.2+    20040818  941  0.2+  0.1+
 
 
 

 

http://cfa-www.harvard.edu/mpec/K04/K04Q19.html

 

The Lowell Observatory services report the following :

 

Asteroid Observation Strategy Chart Builder

Strategy cannot be calculated.

An observing strategy for 2004 QP cannot be computed because we are unable to compute the asteroid's covariance matrix. This condition arises either when the asteroid's differentially corrected orbital elements cannot be computed (an eccentricity-assumed orbit is listed in astorb.dat) or, more likely, when we do not have a complete astrometric data set. The covariance matrix is required to compute the ephemeris uncertainty, and hence the observational strategy.

 

 

 

 

 

(1)   astrometrica is an excellent program by Herbert Raab with functionality to track and stack images allowing modest size telescope to reach very faint bodies provided enough integration time is available. http://www.astrometrica.at

 

Thanks to the minor planet center, Gareth Williams and Tim Spahr, thanks to the Lowell observatory for the online services, thanks to Herbert Raab for astrometrica, thanks to Rafael Ferrando, Peter Birtwhistle and Michel Ory for their effort in observing and thanks to Ramón Naves for his first calculation of the orbital elements.