State transitions in black hole Xray binaries are likely caused by gas evaporation from a thin accretion disk into a hot corona. We present a heightintegrated version of this process, which is suitable for analytical and numerical studies. With radius
We develop a Newtonian model of a deep tidal disruption event (TDE), for which the pericenter distance of the star,
 Award ID(s):
 2006684
 Publication Date:
 NSFPAR ID:
 10362619
 Journal Name:
 The Astrophysical Journal
 Volume:
 926
 Issue:
 1
 Page Range or eLocationID:
 Article No. 47
 ISSN:
 0004637X
 Publisher:
 DOI PREFIX: 10.3847
 Sponsoring Org:
 National Science Foundation
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Abstract r scaled to Schwarzschild units and coronal mass accretion rate to Eddington units, the results of the model are independent of black hole mass. State transitions should thus be similar in Xray binaries and an active galactic nucleus. The corona solution consists of two powerlaw segments separated at a break radius ${\stackrel{\u0307}{m}}_{c}$r _{b}∼ 10^{3}(α /0.3)^{−2}, whereα is the viscosity parameter. Gas evaporates from the disk to the corona forr >r _{b}, and condenses back forr <r _{b}. Atr _{b}, reaches its maximum, ${\stackrel{\u0307}{m}}_{c}$ . If at ${\stackrel{\u0307}{m}}_{c,\mathrm{max}}\approx 0.02\phantom{\rule{0.25em}{0ex}}{(\alpha /0.3)}^{3}$r ≫r _{b}the thin disk accretes with , then the disk evaporates fully before reaching ${\stackrel{\u0307}{m}}_{d}<{\stackrel{\u0307}{m}}_{c,\mathrm{max}}$r _{b}, giving the hard state. Otherwise, the disk survives at all radii, giving the thermal state. While the basic model considers only bremsstrahlung cooling and viscous heating, we also discuss a more realistic model that includes Compton cooling and direct coronal heating by energy transport from the disk. Solutions are again independent of black hole mass, andr _{b}remainsmore » 
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