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"Peremennye Zvezdy", Prilozhenie, vol. 7, N 9 (2007)

New CCD Minima of DM Del

A. Samokhvalov
Russian Federation, Surgut

ISSN 2221–0474

Received:   18.03.2007;   accepted:   22.03.2007
(E-mail for contact: sav@surgut.ru)

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Star Name: DM Del, BD+13 4478, SAO 106356, PPM 138789 Coordinates (J2000): 20 39 37.01, +14 25 43.1 Variability type: EB;   Limits, System: 8.58 - 9.11 ;   Spectrum: A2V Period: 0.8446725 d;   Epoch(min): JD 2454062.1749

Remarks:

I present my CCD photometry of DM Del, an eclipsing binary with variable orbital period. The data were obtained in November - December, 2006 at my small private observatory with a CCD camera SBIG ST-7XMEl and photo lens Rubinar 5.6/500 (D=89.29 mm, F=475 mm) without filter. A total of 785 images with 20-second exposures were obtained on 10 nights (November 2 - December 9, JD2454042 - 2454079, see attached data file). Basic reduction of images (for dark current, flat field, and bias) was carried out with the CCDSoft; the astrometric solution and photometry, with the MaxIm DL software. The comparison and check stars were: comp = SAO 106351 (8.82 mag) and check = GSC 1100-00646 (9.69 mag). Three epochs of the primary minimum were determined based on our photometry using the Minima v2.3 software by Dr. Bob Nelson: 2006 November 22: 2454062.1749; 2006 November 28: 2454068.0876; 2006 December 09: 2454079.0684. I used the new epoch of minimum (HJD2454062.1749) and the period taken from the Brno database of times of minima and maxima (0.8446725 days, see http://var.astro.cz/ocgate/) to plot the phased light curve. Acknowledgments: I would like to thank N. N. Samus, S. V. Antipin and A. V. Khruslov for helpful discussion.