Astronomers discover a peculiar cataclysmic variable star


Prime: Lengthy-term ATLAS gentle curve of J1344, consisting of c- and o-band observations. The shaded area signifies the time of the TESS observations. Center: TESS gentle curve of J1344. Backside: Energy spectrum of the TESS gentle curve. Credit score: Littlefield et al, 2023

Utilizing NASA’s Transiting Exoplanet Survey Satellite tv for pc (TESS), astronomers have found a peculiar cataclysmic variable star. The newly discovered system, designated SDSS J134441.83+204408.3 (or J1344 for brief) is a extremely asynchronous, short-period magnetic cataclysmic variable, regardless of its excessive floor area energy. The discovering is reported in a paper printed January 13 on the arXiv preprint server.

Cataclysmic variables (CVs) are binary star systems consisting of a white dwarf major that’s accreting matter from a traditional star companion. They irregularly enhance in brightness by a big issue then drop again right down to a quiescent state. Polars are a subclass of cataclysmic variables distinguished from different CVs by the presence of a really sturdy magnetic area of their white dwarfs.

When white dwarfs in CVs have a area energy over 10 MG, it’s anticipated to synchronize its rotational frequency to the binary orbit frequency, as a result of steep radial dependence of the magnetic area. Nevertheless, a crew of astronomers led by Colin Littlefield of the Bay Space Environmental Analysis Institute in Moffett Discipline, California, stories the detection of a cataclysmic variable that defies these expectations, due to this fact difficult present theoretical fashions.

“What makes J1344 outstanding is the mix of three parameters: its reasonably excessive magnetic-field energy, its quick orbital interval, and its excessive diploma of asynchronism. Collectively, these properties paint an fascinating image of a magnetic CV that will usually be anticipated to be synchronous, however is not,” the researchers defined.

At a distance of some 1,950 light years, J1344 was initially categorized as a synchronous polar. The brand new TESS information point out that J1344 has a excessive floor area energy of about 56 MG, quick orbital interval of some 114 minutes and due to this fact additionally a comparatively quick orbital separation. Moreover, the brand new observations discovered that this technique showcases an asynchronous rotation as its spin-to-orbit ratio is at a stage of 0.893, which is uncommon for magnetic CVs.

The astronomers underlined that the extremely asynchronous rotation in J1344 is a problem for theoretical research of spin-period evolution. They famous that it proves {that a} floor area energy increased than 10 MG and quick binary separation doesn’t assure {that a} system will quickly synchronize.

All in all, the researchers suppose that some mixture of a weakly magnetic secondary star or an unusually large white dwarf is essentially the most believable speculation that might clarify the failure of J1344 to attain synchronous rotation. In line with them, the case of J1344 means that another CVs categorized as synchronous polars have to be revisited as they could be asynchronous methods.

“J1344’s skill to efficiently masquerade as a synchronous polar for a decade means that different nominally synchronous methods may also be asynchronous. It is going to be essential to look at the TESS gentle curves of all polars to seek for any such methods,” the authors of the paper concluded.

Extra data:
Colin Littlefield et al, SDSS J134441.83+204408.3: A extremely asynchronous, short-period magnetic cataclysmic variable with a 56 MG area energy, arXiv (2023). DOI: 10.48550/arxiv.2301.05723

Journal data:
arXiv


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Astronomers uncover a peculiar cataclysmic variable star (2023, January 25)
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