The common-envelope process is a complicated phase in binary evolution. A lot of effort has been dedicated to study the common-envelope stage, but many questions related to this process are yet to be answered. If one member of the binary survives the common-envelope phase, the binary will emerge as a white dwarf accompanied by a low-mass main sequence star in close orbit, often referred as a post common-envelope binary (PCEB). SDSS J0745+2631 is among the list of newly found PCEBs from the Sloan Digital Sky Survey (SDSS). This star is proposed to be a strong eclipsing system candidate due to the ellipsoidal modulation in its light curve. In this work, we aim to conrm the eclipsing nature of SDSS J0745+2631 and to determine the stellar and orbital parameters using the software Binary Maker 3.0 (BM3.0). We detected the primary eclipse in the light curve of SDSS J0745+2631 in our follow-up observation from January 2014 using the ULTRASPEC instrument at the Thai National Observatory. The data obtained on 7th and 8th January 2014 in g filter show an evident drop in brightness during the eclipse of the white dwarf, but this eclipse is less prominent in the data taken on the next night using a clear filter. According to our preliminary model, we find that SDSS J0745+2631 hosts a rather hot white dwarf with an eective temperature of 11500K. The companion star is a red dwarf star with a temperature of 3800K and radius of 0.3100 R⊙. The red dwarf star almost fills its Roche lobe, causing a large ellipsoidal modulation. The mass ratio of the binary given by the Binary Maker 3.0 (BM3.0) model is M2/M1 = 0.33.

ABSTRACT
1. INTRODUCTION
2. OBSERVATIONS AND DATA REDUCTION
3. RESULTS
4. DISCUSSION
5. SUMMARY
REFERENCES

• Niwat Hemha(School of Physics, Institute of Science, Suranaree University of Technology)
• Nuanwan Sanguansak(School of Physics, Institute of Science, Suranaree University of Technology/National Astronomical Research Institute of Thailand)
• Puji Irawati(National Astronomical Research Institute of Thailand)
• Vik Dhillon(University of Sheffield)
• Tom R.Marsh(University of Zielona Gora)