Research Projects: Eclipsing Binary Stars and
Delta Scuti stars ..... or a combination of both!!
| Eclipsing binaries are double star systems with orbital
planes so close to the observer's line of sight that both components
periodically eclipse each other. If the orbit is elliptical, it is possible
that only one component eclipses the other. The apparent combined brightness
changes with a period coincident with that of the components' orbital
motion. Eclipsing binary light curves enable astronomers to derive stellar
masses and other fundamental parameters. Delta Scuti Stars are variable stars of spectral type A or F
with a pulsation period less than 0.3days. Light amplitudes in V range of a
few thousandths of a magnitude to 0.8m with a typical amplitude of 0.02m. |
| Research project: Variable Components
of Binary or Multiple stars:
The aims are a) to better understand the pulsation(s) (of d Scuti stars) by gaining information on the physical parameters of the variable component exploiting the binary nature of the system and b) to study the effect of binarity on the pulsation characteristics, i.e. the interaction pulsation-binarity, of short-period pulsators. Since the purpose of studying pulsating stars is to probe their stellar interiors (asteroseismology), and since more than 50 percent of all stars are expected to be binaries, understanding the effects of binarity upon the pulsations is of crucial importance. |
Discovered at Beersel Hills Obs:Algol type star TU Her contains a short period
pulsating component !
| TU Her was observed at Hoher List observatory for one night,
by Patricia Lampens and Paul Van Cauteren, with the 1m telescope.
Unfortunately the star showed an eclipse. The observations were performed
in the frame of a search for pulsating components in Algol-type stars,
coordinated by Dr David Mkrtichian of Seoul University, Korea. Later the star was observed several nights at BHO, with the 0.4m telescope. During several nights, the light curve showed pulsations. To be absolutely certain about the short period pulsations, confirmation was asked and obtained from Dr Anton Strigachev, Bulgaria, observing at Skinakas, Kreta with a 1.2m telescope and from S L Kim and Y Kang, Korea using the 1-m reflector of Mt Lemmon Observatory located in Arizona The paper describing this discovery was published in IBVS (2004, nr 5572)
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| HIP 113790: Multiperiodic delta scuti star Discovered by Yves Fremat to be a delta scuti star, Hip113790 was subject to a multi-site campaign organised by Yves and by Patricia Lampens. |
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| Observations were obtained from CW Robertson, Kansas USA, from Stelios Klidis, Athens, Greece, and from Panos Niarchos and his team, observing also in Athens. And of course we observed the star from Beersel Hills Obs!! | ||
| CW Robertson with his son and his 30cm telescope. |
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| Stelios Klidis with his telescope on a rooftop in Athens, Greece. |
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