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AAVSO Special Notice #148: Long-term monitoring of the suspected white dwarf binary V1412 Aql AAVSO HOME > publications > special notice

AAVSO Special Notice #148

Long-term monitoring of the suspected white dwarf binary V1412 Aql
February 26, 2009

Dr. Arlo Landolt (LSU) has requested a campaign to perform long-term
photometric monitoring of the suspected white dwarf binary V1412 Aql, a
carbon white dwarf (spectral type DQ7; V=15.75) which has undergone deep
(3-4 magnitude) fadings on at least two occasions.  The depth of the
changes suggest eclipses by an unseen object.  Observations in the near
infrared by Zuckerman and Becklin (1988) showed no sign of a secondary,
which suggests that any single eclipsing body is substellar, with an
effective temperature less than 1200 K.  If the causes of the fadings
are eclipses as suspected, then this could be a white dwarf with a
transiting exoplanet.

Observers are asked to perform nightly observations of V1412 Aql during
the next year to search for variability in this star.  Visual estimates
and filtered and unfiltered CCD observations are useful; time-series are
not required at this time unless the object goes into eclipse.  Visual
fainter-than estimates below the typical brightness of m(vis) = 15.8 +/-
0.3 are valuable, especially if it is clearly fainter than m(vis) =
16.5.  Because the interval between and duration of eclipses are
unknown, this is largely an exploratory project.  Nightly monitoring by
a number of observers around the world should be able to provide
sufficient coverage to detect eclipses with a period shorter than one
year.  Please submit your data as promptly as possible, and please
contact the AAVSO immediately if there is any indication of an
eclipse/fading.  If you do detect an eclipse, please obtain time series
photometry, preferably with a signal-to-noise ratio of at least 3-5, and
higher if at all possible.

Observers should note that V1412 Aql has a very high proper motion of 
more than 0.6"/year, and both DSS and plotted (NOMAD) charts will not
reproduce the current position of this star on the sky.  Observers
are asked to obtain comparison star magnitudes and positions from VSP;
a current, 8.7'x8.7' finder chart showing the proper position of the 
variable is available at this URL:

V1412 Aql (AUID 000-BDF-742) is located at the following coordinates
(J2000, epoch 2008.9, from A. Henden):

RA: 20 13 55.53 , Dec +06 42 39.9

Charts for the field of V1412 Aql may be plotted using VSP:

Please refer to the current finder chart given above for the location
of the variable, and note it will move slightly during the course
of the year.

For more information on this campaign, please see the campaign page
on the AAVSO website:

Please report all observations to the AAVSO as "V1412 AQL".

This AAVSO Special Notice was prepared by Matthew Templeton.


Information on submitting observations to the AAVSO may be found at:


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