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Special Notice #148: Long-term monitoring of the suspected white dwarf binary V1412 Aql

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: http://www.aavso.org/images2/v1412aql_sro_v.jpg]

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:

http://www.aavso.org/observing/charts/vsp/index.html?pickname=V1412%20Aql

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: http://www.aavso.org/news/v1412aql_campaign.shtml

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

This AAVSO Special Notice was prepared by Matthew Templeton.

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