Utilizing the Hubble Area Telescope (HST) and the Chandra X-ray Observatory, astronomers have taken a more in-depth take a look at a short-period high-mass X-ray binary often known as CXOU J121538.2+361921. Outcomes of the observational marketing campaign, offered July 13 on the preprint server arXiv, shed extra gentle on the properties of this method.
X-ray binaries are composed of a traditional star or a white dwarf transferring mass onto a compact neutron star or a black hole. Based mostly on the mass of the companion star, astronomers divide them into low-mass X-ray binaries (LMXBs) and high-mass X-ray binaries (HMXBs).
Situated some 9.8 million light years within the galaxy NGC 4214, CXOU J121538.2+361921 (or NGC 4214 X-1) is a luminous HMXB, showcasing X-ray eclipses with a interval of three.62 hours. The eclipse interval is, most definitely, additionally the orbital period, which makes NGC 4214 X-1 the shortest-period HMXB system identified so far. Nonetheless, though many research of this method have been performed, its properties aren’t effectively understood.
That’s the reason a group of astronomers led by Zikun Lin of the College of Chinese language Academy of Sciences in Beijing, China, determined to research NGC 4214 X-1 with Hubble and Chandra telescopes.
“We mixed new and archival Chandra and HST knowledge for a research of the short-period, eclipsing X-ray binary NGC 4214 X-1,” the researchers wrote within the paper.
The observations confirmed that NGC 4214 X-1 remains to be energetic and nonetheless showcasing eclipses, with an out-of-eclipse luminosity at a degree of about one duodecillion erg/s. The eclipse interval and the common eclipse period time have been confirmed to be roughly 3.6 and 0.57 hours, respectively.
The eclipse fraction was calculated to be about 0.16, which allowed the researchers to estimate the minimal mass ratio of the system—roughly 2.0. This discovering additional confirms the HMXB nature of NGC 4214 X-1.
The stellar density of the donor star was calculated to be roughly 5.9 g/cm3. This end result, along with the mass ratio and quick binary interval, counsel that the donor is a Wolf-Rayet (WR) star or an intermediate-mass stripped helium star.
Furthermore, based mostly on HST observations, Lin’s group discovered an optical counterpart to NGC 4214 X-1, with an obvious brightness of 24 magazine. The optical supply consists of two clearly distinct parts: a blue emitter (with a temperature of about 60,000–80,000 Okay and attribute radius of two.0 solar radii) and a purple emitter (with a temperature of about 2,500–3,000 Okay and attribute radius of some 400 solar radii).
The authors of the paper concluded that the blue element additional helps the WR state of affairs for the donor star in NGC 4214 X-1. They added that the purple element could also be an irradiated circumbinary disk.
Extra data:
Zikun Lin et al, On the Quick-Interval Eclipsing Excessive-Mass X-ray Binary in NGC 4214, arXiv (2023). DOI: 10.48550/arxiv.2307.06993
Journal data:
arXiv
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Observers examine a short-period X-ray binary system (2023, July 24)
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