2 research outputs found
Decoding the X-ray flare from MAXI J0709-159 using optical spectroscopy and multi-epoch photometry
We present a follow-up study on the recent detection of two X-ray flaring
events by MAXI/GSC observations in soft and hard X-rays from MAXI J0709-159 in
the direction of HD 54786 (LY CMa), on 2022 January 25. The X-ray luminosity
during the flare was around 10^(37) erg/s (MAXI), which got reduced to 10^(32)
erg/s (NuSTAR) after the flare. We took low-resolution spectra of HD 54786 from
HCT and VBT facilities in India, on 2022 February 1 and 2. In addition to
H-alpha emission, we found emission lines of He I in the optical spectrum of
this star. By comparing our spectrum of the object with those from literature
we found that He I lines show variability. Using photometric study we estimate
that the star is having effective temperature of 20000 K. Although HD 54786 is
reported as a supergiant in previous studies, our analysis favours it to be
evolving off the main sequence in the Color-Magnitude Diagram. We could not
detect any infrared excess, ruling out the possibility of IR emission from a
dusty circumstellar disc. Our present study suggests that HD 54786 is a
Be/X-ray binary system with a compact object companion, possibly a neutron
star.Comment: 9 pages, 5 figures, 1 table, accepted for publication in ApJ