EE Cep observing campaign 2025-2026
Abstract:
The AAVSO requests observers' assistance monitoring the long-period (5.61 years) eclipsing binary EE Cep for a campaign that will last from the beginning of October until the end of the year. EE Cep is member of a short list of so named “disk-occulting systems”, resulting in very long eclipses (57 days in this case) compared to what we expect from ordinary eclipsing binary stars. A champion in this family is Epsilon Auriga with a period of 27.08 years and eclipse duration of about two years. Dariusz Kubicki (Nicolaus Copernicus University has a website (https://sites.google.com/site/eecep2020campaign/), on it he includes figures showing photometry from previous eclipse campaigns for EE Cep.
Justification:
Though EE Cep has been observed a number of times, like many other disk-occulting systems, it still needs thorough observation in order to better characterize its evolution. The beginning of the ingress will take place around the 15th of October (JD 2,460,964), the mid-eclipse is predicted on the 13th of November (JD 2,460,993), and the end of the egress is expected on the 11th of December (JD 2,461.021). It is recommended to start observing in August and continue at least one month after the end of the eclipse. All photometric optical (UBVRI) and especially infrared (JHK etc.) data will be useful. "Before the ingress one or two measurements during the night will be useful, whereas during the eclipse we count on the highest possible time resolution of observations (long series).
Requested Data Types:
Photometry, Spectroscopy
Targets
| Name | Magnitude | Variability Type | Photometry Notes | Spectroscopy Notes |
|---|---|---|---|---|
| EE Cep | 10.72 | EA |
Cadence: Custom Precision: 100 |
Cadence: Custom Resolution: 10000 Desired SNR: 100 |
Spectroscopy Lines:
H-gamma (4340.0 Å), H-beta (4861.0 Å), Sodium Doublet (5890.0 Å), H-alpha (6563.0 Å)
Photometry Filters:
U (Johnson), B (Johnson), V (Johnson), R (Cousins), Other (Please Specify)
Comparison Stars:
Finder charts with comparison stars may be created using the AAVSO Variable Star Plotter (VSP, https://apps.aavso.org/vsp/). For comp and check star we suggest those with the label 104 and 112. If you use “ensemble “, add as many as you see fit.
Co-Authorship
Observers are not eligible for co-authorship.
Additional Observer Input:
In addition to photometry filter U, B, V, R, I and infrared J, H, K etc. would be welcome. Spectroscopic observations with high resolution (R~10000 or higher) are also recommended. Observing Hα, Hβ and Hγ lines and ion Na I doublet for analysis of line profiles will be useful. In the case of spectrographs with low-resolution, flux calibration will be essential to make them useful in analyses.
Additional Submission Location:
Not provided
Forum URL
https://forums.aavso.org/t/observing-campaign-894-ee-cep-observing-campaign-2025-2026/2999
Notes:
Photometric observations should be submitted to the AAVSO International Database using the name EE CEP. Spectroscopy reports should be submitted to the AAVSO Spectroscopic Database (https://www.aavso.org/apps/avspec/).