1 / 16

HD 50844

HD 50844. Poretti et al. (2005) : „Potential secondary target in the Anticenter dir.” „a 2M Sun , slightly evolved object”

deacon
Download Presentation

HD 50844

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

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

  2. Observations • 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

  3. 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

  4. Work with the data • 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 (s) in C3-C4 • Final differential (V-C4) lightcurvesof the 4 used nights:

  5. Frequency analysis • PERIOD04 [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

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

  7. The „new” variable • RA (J2000): 06h 55m 11.7s • 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.

  8. Analysis of UCAC2 31295533 • The same (and also the best) 4 nights were used in PERIOD04 • 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 (mV=12.8) then HD 50844 (mV=9.1), so it is harder to get accurate frequencies • The analysed light curves:

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

  10. 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

More Related