Novae-like System Investigated: Features Revealed

evidence of disk wind

A team of researchers examined the long-term photometric results of the nova-like system, dubbed SW Sextantis. The findings are truly astonishing.

Researchers discovered that the light variation of that system displays a possible quasi-periodic quivering with the time-scale of approximately a decade. 

Mixed with the change of the orbital period, the team concluded a strong wind exists in the system. How could this be possible? Here is what you need to know. 

Binary Systems and Cataclysmic Variables

According to the team’s research, cataclysmic variables and interacting binary systems comprising a late-type Roche-lobe-filling red dwarf and a white dwarf. Researchers explained that the mass is transferred from the so-called companion to the white dwarf via the Lagrange point. It also produces an accretion disk enclosing stream from the secondary crashes with the disk. 

The SW Sextantis-type nova-like stars possess extremely high mass-transfer rates and incredibly stable accretion disk structures, which keep these systems in determining bright states. Also, being a prototype, this type of nova-like star has attracted the affluence of spectroscopic observational and photometric studies. 

The Team’s Findings

The team used the data from the Digital Access to a Sky Century at Harvard (DASCH) and the American Association of Variable Star Observers (AAVSO) databases and discovered that SW Sextantis had a long-term brightness quivering of approximately a decade. The synergy between the inner disk and the fast-rotating white dwarf might be responsible for this phenomenon. 

Furthermore, some telescopes were also utilized to analyze the eclipse profiles. The profiles with phase widths of 0.06 centering on the mid-eclipse were matched using a Gaussian function. What the team found, however, was truly intriguing. 

Researchers discovered that the orbital period displays wiggle from 1980 to 2015. Then it decreased severely until this year when the observations stop. 

A third element can trigger that wiggle. The third companion’s minimum mass is approximately 0.014 solar mass with a separation of 10.52 AU (astronomical units), which shows that it might be a massive planet. 

The recent research proves that SW Sextantis is exceptionally incredible, and it offers essential data for comprehending the disk activity and the evolution of the cataclysmic variables. 

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