2. Poretti et al. (2005): –„Potential secondary target in the Anticenter dir.” –„a 2M Sun, slightly evolved object” –„High-res. spectroscopy: perturbed line profiles: multiple star, or more probably a  Scuti showing high degree modes. The considerable photometric amplitude suggests the presence a of dominant low-degree mode.” HD 50844 Source: Poretti et al. (2005)

3. Piszkéstető (MTA KTM CsKI) –d = 1m, f = 13500mm, RCC –Roper Scientific 1300B CCD 20×20μm, 1340×1400 pix., 7’×7’ FOV –2006. dec. – 2007. febr.: 7 nights –V filter Observations

4. Data reduction IRAF (by the observers) Comparison stars: –„bright” –„small” B-V diff. –C4 & C3 is OK Photometry of min. 12 stars on every frame Image source: DSS POSS2

5. Searching for other variables in the field: –1 new variable! -> UCAC2 31295533 Work with HD 50844 –Cut points affected by the changing weather (clouds) –Cut intervals with higher deviation (  ) in C3-C4 –Final differential (V-C4) light curves of the 4 used nights: Work with the data

6. P ERIOD 04 [Lenz, P., Berger, M. (2005)] –Discrete Fourier Transform –min. S/N=4 Noise: max[A,B] –A: average amplitude of the whitened power spectrum in a ±10 c/d interval around the peak –B: average amplitude of the original power spectrum in the interval of [50:100] c/d (clearly beyond the frequency range of the star) –Analysis of weighted data & averaged data (60 sec) Test of the program -> same results! On the next slides: whitening steps with curve-fits to the observed data and a calculated continuous light curve Frequency analysis

10. Frequency content of HD 50844 2 dominant and 3 other frequencies were found HD 50844 could be a good secondary target.

11. RA (J2000): 06 h 55 m 11.7 s DEC (J2000):-01° 05’ 02.3” –Names: USNO-A2.0 0825-03492210 & UCAC2 31295533 from the Catalog of Astrometric Standards & The Second U.S. Naval Observatory CCD Astrograph Catalog Is it really a „new” variable? -> YES! –ASAS Catalog of Variable Stars: no entry around this position –GCVS: no entry –VSX (International Variable Star Index): no entry –Personal communication with Dr. József Benkő: this object is not present in their database (too short period and too small amplitude to be traceable in the ROTSE-I data) –No sign of variability in Aladin. The „new” variable

12. The same (and also the best) 4 nights were used in P ERIOD 04 –Full Fourier-analysis for the best 2 nights was also performed to compare results Work with the weighted data –30s points with a weight of 3, 20s points with a weight of 2, etc. Much fainter (m V =12.8) then HD 50844 (m V =9.1), so it is harder to get accurate frequencies The analysed light curves: Analysis of UCAC2 31295533

13. steps for all the 4 nights and for only the „best” 2 nights On the next slides: various fits to the observed light curves Analysis - Whitening

15. Frequency content of the new variable Four significant frequencies were found both in the 4 and the 2 day sample. Further observations are needed to determine values more precisely. Could it be a possible CoRoT target? –For the Seismology field: NO (too faint) –Exoplanet field: YES(11.5<mV<16) 32s integration time: OK (but there are only 500 windows per CCD for this) 512s integration time: further simulations needed