Models of >2000 ASAS bright contact and close binaries.

B. Pilecki^†, G. Pojmański^†, D. M. Szczygieł^†

^†Warsaw University Astronomical Observatory, Al. Ujazdowskie 4, 00-478 Warszawa, Poland

Abstract

There are about 11000 eclipsing binaries (including almost 5400 contact binaries) in the ASAS catalogue - ACVS. Here we present models for more than 2000 contact and close binaries brighter than 11.5 mag in V. Parameters included are: temperatures, inclination, radii relative to Roche lobe radii and mass ratio. In the process o modelling we used both V and I band data.

On-line data

• Individual object data (you can get all data for an individual star here by providing its ASAS or GCVS ID):

• Light curves gallery (you can browse through light curves for preselected lists of stars):

  • ALL - All ~2800 modelled binaries (or their random sets of one, three, five or ten)
  • SN₆ - ~2200 stars with signal to noise ratio (S/N) greater than 6
  • S_2.4SN₆ - ~2000 stars with good fit and S/N>6
  • QS_2.4SN₆ - ~1200 stars with well or acceptably determined mass ratio from S_2.4SN₆ sample
  • QS_2.4SN₆ sorted by ER - as above sorted by eclipse rate
  • with linear dP/dt - all with linear period change
  • with cyclic dP/dt - all with cyclic period change
  • with high BT - all with brightness variation
  • ALL sorted by S/N in V - sorted by signal to noise ratio
  • DDO subsample - Stars which were observed spectroscopically in DDO.

• Data tables:

  • Model parameters as used in the publication and table description.
  • More parameters with errors and table description.

• Animated plots (period range changes with time):

  • R vs. T_ratio - Roche lobe filling vs. temperature ratio; see also plot for filling R>0.8 and for near-contact and contact binaries.
  • r₁ vs. r₂ - radii relative to Roche lobe radii of both components; see also plot centered and zoomed at transition between near-contact and contact binaries and plot showing only contact binaries.

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Long-term variation of 6510 ASAS bright contact and close binaries.

B. Pilecki^†

^†Warsaw University Astronomical Observatory, Al. Ujazdowskie 4, 00-478 Warszawa, Poland

Abstract

Because of proximity close binaries often shows eclipses. It is also known that other kind of variabilities may affect their light curves which is mostly a result of high magnetic activity, as these stars are fast rotators and have often convective envelopes. Observations of ASAS project now spans for more than 8 years which allows us to investigate long-term variability of the order of years. We chose all 6510 eclipsing binaries that are brighter than V=12 mag and have more than 100 measurements. After subtraction of eclipsing variability model, residual light curves were investigated for linear and cyclic behaviour. Influenced by sparse data coverage the applied method was sensitive mostly to effects which affect brightness of the system at all phases. This limitation however turns out to be an advantage because a lot of such stars were found mostly among short period and thus contact binaries. Such behaviour is unexpected because magnetic activity should only change brightness of one star which than results in change of eclipse depths.

On-line data

• Light curves gallery (you can browse through light curves for preselected lists of stars):

  • S/N_IMP > 10% - ~600 with signal to noise ratio improvement greater than 10%
  • Whole set - All ~2800 modelled binaries (or their random sets of one, three, five or ten)

Data files:

• BT statisics for stars with prominent average brightness variation and table description.

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ASAS Eclipsing Binaries with Cyclic and Linear Period Change.

B. Pilecki^†

^†Warsaw University Astronomical Observatory, Al. Ujazdowskie 4, 00-478 Warszawa, Poland

Abstract

Three years ago we have detected 31 eclipsing binaries with period change in All-Sky Automated Survey (ASAS) data which have timespan of about 5 years. Because detection limit scales with squared timespan of observations in this attempt we could detect a lot more of objects that show period change. New method that was applied this time allows us also to detect not only linear but also cyclic period changes. We present YY objects that have more than one cycle covered by ASAS observations (hence cycle is shorter than 4 years) and 85, where we can notice a departure from linear change. Also a list of 625 objects that have linear period change is included. Some interesting objects are described in more details. Stars with negative and positive linear period change are almost equally numerous, which is probably due to the fact, that we see only a part of longer cycles. O-C diagrams are presented.

On-line data

• Light curves gallery (you can browse through light curves for preselected lists of stars):

  • Linear - stars with linear period changes.
  • Cyclic - stars with cyclic period changes.
  • Whole set - All 6510 tested binaries (or their random sets of one, three, five or ten).

• Data Table that contains parameters of linear and non-linear ephemerides:

  • Linear ephemerides of all analysed binaries and table description.
  • Non-linear ephemerides of binaries with linear or cyclic period changes (if detected) and table description.

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Zagadnienie kontaktu w układach zaćmieniowych na podstawie danych ASAS (PhD thesis)

B. Pilecki^†

^†Warsaw University Astronomical Observatory, Al. Ujazdowskie 4, 00-478 Warszawa, Poland

Description:

This is a digital version of my PhD thesis (in Polish). The title in English is: "The issue of contact in eclipsing binaries using ASAS data."

On-line data

• bp_thesis.ps (28 MB, lang: pl)