1318 new variable stars in a 0.25 square degree region of the Galactic plane

Abstract

analysis method as implemented in the pysis3 code and resulted in more than 500 000 lightcurves of stars down to a magnitude limit of R ∼ 24.5. A search for variable stars resulted in the detection of 1318 variables of different types. 1011 of these are eclipsing or contact binary stars. A number of the contact binaries have low mass-ratios and several of the detached binaries appear to have low-mass components. Three candidate contact binaries have periods at the known cut off including two with periods lower than any previously published. Also identified are 3 possible pre-main sequence detached eclipsing binaries.

Four ultra-short-period eclipsing M-dwarf binaries in the WFCAM Transit Survey

“…Maceroni & Montalbán () found an almost twin M3 system (OGLE BW3 V38; semi‐detached, P = 0.1984 d) with strong chromospheric emission and masses of 0.44 and 0.41 M ⊙ . Other surveys found only binaries with P > 0.21 d. Miller et al () found seven candidate contact binaries with periods between 0.2109 and 0.23 d in a 0.25 deg 2 Galactic plane survey with the European Southern Observatory 2.2‐m telescope, and Weldrake et al () found a P = 0.2155 d system in the globular cluster 47 Tuc, whereas Pribulla, Vanko & Hambalek () report a P = 0.211249 d system. The left‐hand panel of Fig.…”

Unsupervised classification of eclipsing binary light curves throughk-medoids clustering

“…We have classified 1318 LCs of eclipsing binaries along with some possible pulsating stars in the Galaxy which lie primarily along the spiral arms. k-medoids method in combination with CID has been employed for crossverification of the subjectively classified variable stars (Miller et al 2010), gives rise to two clusters k1 and k2, where the resulting clustering has been assessed as quite good in terms of ASW. We observe that k1 consists of all three categories EB, EW and PUL in very close number, whereas the number of EA is comparatively small.…”

“…During the past decades many photometric surveys ( The above observations are generally related to Galactic Bulge, Magellanic clouds or globular cluster surveys. Miller et al (2010) have carried out observations of Es (along with some possible pulsating stars) covering 0.25 square degree region of the Galactic plane centered on Galactic coordinates (l, b) of (330.94, −2.28) deg. The majority of stars in the above region are thought to be associated with the Normal Spiral Arm.…”

“…7179 LCs) has been compiled by Malkov and Avvakumova (2013) along with update on some previous catalogues (Malkov et al 2006;Avvakumova et al 2013). However, in the present paper we decided to focus on the LCs of Es of Miller et al (2010), as we are interested in the classification of binary stars in our Galaxy associated with the spiral arms.…”

“…This separates the stars according to their geometrical configuration in a more scientific way compared to the subjective traditional classification scheme. The light curves in the Galaxy, subjectively grouped in four categories (EA, EB, EW, PUL) in Miller et al (2010), have been found to consist of two optimum groups containing primarily eclipsing binaries corresponding to bright, massive systems and fainter, less massive systems. Our technique has been assessed in terms of clustering accuracy measure the Average Silhouette Width, which shows the resulting clustering pattern is quite good.…”