Tidal capture of stars by supermassive black holes: implications for periodic nuclear transients and quasi-periodic eruptions
ABSTRACT

Stars that plunge into the centre of a galaxy are tidally perturbed by a supermassive black hole (SMBH), with closer encounters resulting in larger perturbations. Exciting these tides comes at the expense of the star’s orbital energy, which leads to the naive conclusion that a smaller pericentre (i.e. a closer encounter between the star and SMBH) always yields a more tightly bound star to the SMBH. However, once the pericentre distance is small enough that the star is partially disrupted, morphological asymmetries in the mass lost by the star can yield an increase in the orbital energy of the surviving core, resulting in its ejection – not capture – by the SMBH. Using smoothed particle hydrodynamics simulations, we show that the combination of these two effects – tidal excitation and asymmetric mass-loss – results in a maximum amount of energy lost through tides of $\sim 2.5{{\ \rm per\ cent}}$ of the binding energy of the star, which is significantly smaller than the theoretical maximum of the total stellar binding energy. This result implies that stars that are repeatedly partially disrupted by SMBHs many (≳10) times on short-period orbits (≲few years), as has been invoked to explain the periodic nuclear more »

Authors:
; ;
Publication Date:
NSF-PAR ID:
10391031
Journal Name:
Monthly Notices of the Royal Astronomical Society: Letters
Volume:
520
Issue:
1
Page Range or eLocation-ID:
p. L38-L41
ISSN:
1745-3925
Publisher:
Oxford University Press
National Science Foundation
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2. Abstract

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4. ABSTRACT

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5. Abstract

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