Contact binaries as viable distance indicators: new, competitive (V)JHK s period-luminosity relations

Xiaodian Chen, Richard De Grijs, Licai Deng

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)


Based on the largest catalogs currently available, comprising 6090 contact binaries (CBs) and 2167 open clusters (OCs), we determine the near-infrared (NIR) JHK s CB period-luminosity (PL) relations, for the first time achieving the low levels of intrinsic scatter that make these relations viable as competitive distance calibrators. To firmly establish our distance calibration on the basis of OC CBs, we require that (i) the CB of interest must be located inside the core radius of its host cluster, (ii) the CB's proper motion must be located within the 2σ distribution of that of its host OC, and (iii) the CB's age, t, must be comparable to that of its host cluster, i.e., Δlog(t yr-1) < 0.3. We thus select a calibration sample of 66 CBs with either OC distances or accurate space-based parallaxes. The resulting NIR PL relations, for both late-type (i.e., W Ursae Majoris-type) and - for the first time - early-type CBs, are as accurate as the well-established JHK s Cepheid PL relations, (characterized by single-band statistical uncertainties of σ < 0.10 mag). We show that CBs can be used as viable distance tracers, yielding distances with uncertainties of better than 5% for 90% of the 6090 CBs in our full sample. By combining the full JHKs photometric data set, CBs can trace distances with an accuracy, σ = 0.05 (statistical) ± 0.03 (systematic) mag. The 102 CBs in the Large Magellanic Cloud are used to determine a distance modulus to the galaxy of (m Mv)LMC0 = 18.41 ± 0.20 mag.

Original languageEnglish
Article number138
Number of pages10
JournalAstrophysical Journal
Issue number2
Publication statusPublished - 1 Dec 2016
Externally publishedYes


  • binaries: eclipsing
  • open clusters and associations: general
  • stars: distances


Dive into the research topics of 'Contact binaries as viable distance indicators: new, competitive (V)JHK s period-luminosity relations'. Together they form a unique fingerprint.

Cite this