October 2, 2015: Further to AAVSO Alert Notice 511, issued in March 2015, Dr. George Rieke (University of Arizona) and colleagues' campaign to monitor planetary debris disks for variability using the Spitzer Space Telescope continues. AAVSO observations are requested to rule out variability of the stars themselves.
The second segment of observations of the four targets takes place from now into January 2016 according to the schedule below.
Target
|
SpT
|
Age
(Myr)
|
Vmag
|
R.A. (2000)
|
Dec. (2000)
|
Sptizer visibility
First segment
|
Sptizer visibility
Second segment
|
|---|---|---|---|---|---|---|---|
| RZ Psc | KOIV | 35 | 11.29 | 01 09 42.06 | +27 57 01.95 | Mar 14-Apr 24 | Oct 10-Nov 20 |
| HD 15407A | F5V | 80 | 6.95 | 02 30 50.66 | +55 32 54.2 | Apr 5-May 24 | Nov 7-Dec 28 |
| V488 Per | KOIV | 60 | 12.83 | 03 28 18.68 | +48 39 48.2 | Apr 17-May 30 | Nov 15-Dec 31 |
| HD 23514 | F5V | 150 | 9.43 | 03 46 38.40 | +22 55 11.2 | Apr 18-May 26 | Nov 13-Dec 23 |
Observers may recall that during the first segment, the stars were extremely near conjunction and very difficult or impossible to observe from the ground. During this second segment, they are much better placed and should be straightforward targets.
As before, observations in V are requested, with a S/N of about 100 so that the accuracy will be 1-2%. Observations should begin at least one week before the visibility window opens and finish one week after the window closes.
No specific comparison stars are assigned for each target, but observers are requested to use only those in the sequences available via the AAVSO Variable Star Plotter (VSP, http://www.aavso.org/vsp). It is essential that observers report the comparison stars used when submitting their observations to the AAVSO.
Observations should be submitted to the AAVSO International Database using the names RZ PSC, HD 15407A, HD 23514, and V488 PER, respectively.
Please see AAVSO Alert Notice 511 for more information about this very interesting campaign.
During a similar campaign in 2013 (see AAVSO Alert Notice 482), AAVSO observers provided data that were critical to its success. Yesterday, Dr. Rieke wrote: "...we really appreciate the support from AAVSO - it is a key part of our science (and resulted in the observers who provided data last time being co-authors of our paper, which seemed to make them quite pleased!)."
This AAVSO Special Notice was compiled by Elizabeth Waagen.
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