Preliminary discussion on IU Per

L. Hric, E. Kundra

Astronomical Institute of the Slovak Academy of Sciences,

059 60 Tatranská Lomnica, Slovak Republic

KOLOS 2011

IU Persei is an eclipsing semi - detached binary with pulsating component. Using our photometric CCD observations in B and V filters we introduce the model of this system in detail. We determined the (O - C) diagram behaviour and geometric and physical parameters of semi – detached system. We detected the short – term variations on the light curve. What's more, we obtained the residua, by comparison of observational and synthetic light curves, of which the detailed period analysis enabled to characterize and localize their source. We explain these variations as the pulsation activity of the primary component typical for the Delta Scuti Stars.

Abstract

Outline

IU Per – overview of the system

Long-term photometric behaviour (activity, BV photometry, period analysis, discovery of 0.3 – 0.65 hours period)

Period analysis of IU Per and pulsation periods

Monitoring of (O – C) diagram

Conection with AG Dra

IU Per – overview of the system

IU Per – overview of the system

Observations

(O – C)

Qian et al. (2001)

By Fitsch (1981) we calculated for the average density of the primary of IU Per and selected periods of pulsations ((0.0125 d, 0.0167 d, 0.0208 d, 0.025 d) we calculated the following values of pulsation constant 0.00635, 0.00846, 0.01058, 0.01270

Fitch (1981) From published models of pulsations of the stars of type sigma scuti (Fitch 1981) we identified for the pulsation constants 0.01058 and 0.01270 the following modes of pulsations: The fifth harmonic radial mode of pulsations 5HThe sixth harmonic non-radial mode of pulsations p7

Resonance in AG DraWe discovered the resonance 14/9 between orbital and pulsation periods.

P orbital = (549.8 ± 0.8) days x 9 = 4948.2 ± 7.2

P pulsation = (352.8 ± 1.1) days x 14 = 4939.2 ± 15.4

42000 43000 44000 45000 46000 47000 48000 49000 50000 51000 52000 53000JD - 2400000 [days]

-160

-150

-140

Ra

dia

l ve

loc

ity

[k

m.s

-1

]

12.0

11.0

10.0

9.0

B [

ma

g]

AG Dra Radial velocity

V

U

B

orb ita l responsepulsation response

orb ita l + pu lsa tion response

12.0

11.0

10.0

9.0

8.0

U [m

ag

]

10.0

9.0

8.0 V [m

ag

]

Thank you for

your attention