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Recent activity at KSE Observatory
--Be sure to check the Archive section for past activity--


December 5, 2014: The rapid fading of the cataclysmic variable star KU Cassiopeia.

KU Cassiopeia is a cataclysmic variable binary star of the SS Cyg type which exhibits rapidly rising and falling outbursts. It last erupted on November 23, reaching a peak visual magnitude of at least 13.5. The rise of the light curve is very rapid, reaching peak brightness from a quiescent level of less than 18th magnitude in just a few hours. The decline back to the quiescent level is also fairly rapid for a cataclysmic variable, taking less than seven days during this last outburst. KU CAS was measured at magnitude 20.5 +/-1.4 (V) on December 5th, making this star one of the faintest objects imaged from KSE Observatory to date.  A plot of the light curve from AAVSO data over the last two years is shown below:

Click on the image to enlarge.

Below are images of KU CAS taken at KSE Observatory during and after the most recent outburst. Click on an image to enlarge.

KU CAS at 13.645 (V)

KU CAS at 13.979 (V)


KU CAS at 20.5 (V)

Time series data taken November 27 and 29th did not show clear patterns over the four hours of observation on each night. The orbital period is listed at 60 days for this system so it's not surprising that the light curve is generally featureless except for a slow decline in brightness over the four hour observation period. Below is the "quick look" plot from the AIP4WIN software which was used to reduce the data on Nov. 29. Each measurement was produced from two minute exposures through a V filter. The points in the top half of the image represent the brightness of KU CAS while the points in the bottom half represent the brightness difference between the comparison and check stars (140 & 144 respectively). See the AAVSO finder chart below for star identifications.


Click on the image to enlarge.



October 29, 2014: "Superhumps" in the light curve of the dwarf nova VSX J213806.5+261957.

VSX J213806.5+261957 is a cataclysmic variable binary star of the WZ Sge type which erupted on October 21, reaching a visual magnitude of at least 9.7. Dr. Matt Templeton of  the AAVSO comments that " its recurrence time of less than five years makes it notable among stars of this class". The AAVSO requested observations of this star, including time series photometry,  in order to gather data on the evolution of the light curve following the outburst. The AAVSO Special Notice #388 link is here: http://www.aavso.org/aavso-special-notice-388

The stars which make up this binary system are in very close orbits with each other, completing an orbit about a common center in approximately 1.5 hours. This can be seen in the light curve from images obtained on October 29, 2014 (UT) at KSE Observatory:

VSX J213806.5+261957

The top curve represents the V-filter magnitude of the variable star and the bottom curve represents the brightness difference between the comparison and check stars. A total of 276, 30 second exposures were made and the light curve spans about four hours of observation time.

A superhump is an elevated outburst in the signal that occurs with a period slightly longer than the orbital period. Two complete superhumps can be seen in the "Quick Look" photometry data plot above. The superhump may be the result of an elongation of the accretion disk in combination with precession. The elliptical disk precesses about the white dwarf over a time interval much longer than the orbital period, causing a slight change in the orientation of the disk over each orbit.

As of November 21, 2014 VSX J213806.5+261957 has faded to about 14.5 magnitude. The AAVSO generated light curve is shown below:

Click on the image to enlarge.

VSX J213806.5+261957 and the comparison/check stars are identified in the KSE Observatory image shown below:

Click on the image to enlarge.


May 4, 2014: An occasional look at nearby galaxies.

With Leo overhead and a rich cluster of bright galaxies following the constellation, I gave into the temptation to image some of the brighter spirals for a chance to stumble on a supernova in the making. Not much luck on that night, which isn't surprising considering that the rate of supernova events in any given galaxy is about one per hundred years!

Here's an example image of NGC 4565 as it appears after an 11 minute exposure through a photometric V filter.

Click on the image to enlarge.








Observing goals:

Most of the observing time at KSE Observatory is devoted to variable star CCD photometry in support of AAVSO observing campaigns and special activities. Objects of interest include cataclysmic variable stars (CV's), high mass x-ray binaries (HMXB), polars, blazars (BL-LAC objects), and extrasolar planets. And there's an occasional solar system planet, asteroid, or comet that also makes the list.

Partial target list:



J2030.5+4751 (High Mass X-Ray Binary)
http://www.aavso.org/aavso-special-notice-213
HBC 722 (Young stellar object)
http://www.aavso.org/aavso-alert-notice-425
BL Lac (Blazar, AAVSO High Energy Network target)
IL Aqr (Magnetically active dwarf, AAVSO Alert #406)
http://www.aavso.org/node/1555/89
3C454.3 (Blazar, AAVSO High Energy Network target)
V455 And (AAVSO Alert Notice #426)
http://www.aavso.org/aavso-alert-notice-426
1ES0120+34 (Blazar, AAVSO High Energy Network target)
TT Ari (Monitor for low state)
3C 66A (Blazar, AAVSO High Energy Network target)
1H0323+342 (Blazar, AAVSO High Energy Network target)
AAVSO 0434+41 (High Mass X-Ray Binary)
http://www.aavso.org/aavso-special-notice-213
NSV 16181 (Magnetically active dwarf, AAVSO Alert #406)
http://www.aavso.org/observing-campaign-monitor-magnetically-active-dwarfs-long-term-variability
V998 Ori (Magnetically active dwarf, AAVSO Alert #406)
FS Aur (Peculiar Dwarf Nova, AAVSO Alert #428)
http://www.aavso.org/aavso-alert-notice-428
SAX J0635+0533 (High Mass X-Ray Binary)
http://www.aavso.org/aavso-special-notice-213
1ES0647+25 (Blazar, AAVSO High Energy Network target)

OI 158 (Blazar, AAVSO/GTN High Energy Network target)

YZ Cmi (Magnetically active dwarf, AAVSO Alert #406)

1ES0806+52 (Blazar, AAVSO High Energy Network target)

MRK 1218 (Blazar, AAVSO High Energy Network target)

OJ 287 (Blazar, AAVSO/GTN High Energy Network target)

NSV 4776 (Magnetically active dwarf, AAVSO Alert #406)

FIRST J1023 (Neutron star binary, millisecond pulsar)
http://www.wired.com/wiredscience/2009/05/missing-link-pulsar/

RY Sex (Magnetically active dwarf, AAVSO Alert #406)

EE Leo (Magnetically active dwarf, AAVSO Alert #406)

CN Leo (Magnetically active dwarf, AAVSO Alert #406)

MRK 421 (Blazar, AAVSO High Energy Network target)

3C 273 (Blazar, AAVSO High Energy Network target)

3C 279 (Blazar, AAVSO High Energy Network target)


Artist's depiction of DQ Herculis, an intermediate "polar" CV binary star.
Image courtesy of NASA/nasaimages.org
Click on the image to enlarge.


A super-massive black hole at the center of galaxy M87 beaming a jet of electrons and sub-atomic particles. Strong magnetic fields and the spin of the black hole are thought to produce the narrow jets which shoot out from the poles in opposite directions. Blazars are galaxies such as M87 where the jet of particles is directed at our line of sight. Image courtesy NASA/hubblesite.org
Click on the image to enlarge.

An artistic view of the accretion disk and the jet of a blazar. Credit: Cosmovision, a group led by Dr. Wolfgang Steffen of the Instituto de Astronomia, UNAM, Ensenada, Mexico.
Click on the image to enlarge.