Brown Dwarfs

Dark Kinetic Heating of Exoplanets and Brown Dwarfs

By Keith Cowing
Status Report
May 11, 2024
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Dark Kinetic Heating of Exoplanets and Brown Dwarfs
Dark kinetic heating of a benchmark brown dwarf, white dwarf, the Sun, and the Earth, all at the local position as a function of both interaction strength α and dark force range λ for 1 GeV dark matter. All these plots assume the object’s maximum capture rate. This map shows pure dark kinetic heating with no Standard Model background. The red dashed line on each plot corresponds to the radius of the given object. For the Sun and the Earth, we show the dark kinetic energy deposition rate E˙ χ as a fraction of the object’s measured power, see text for details. — astro-ph.EP

Dark kinetic heating of neutron stars has been previously studied as a promising dark matter detection avenue. Kinetic heating occurs when dark matter is sped up to relativistic speeds in the gravitational well of high-escape velocity objects, and deposits kinetic energy after becoming captured by the object, thereby increasing its temperature.

We show that dark kinetic heating can be significant even in objects with low-escape velocities, such as exoplanets and brown dwarfs, increasing the discovery potential of such searches. This can occur if there is a long-range dark force, creating a “dark escape velocity”, leading to heating rates substantially larger than those expected from neutron stars.

We consequently set constraints on dark sector parameters using Wide-field Infrared Survey Explorer and JWST data on Super-Jupiter WISE 0855-0714, and map out future sensitivity to the dark matter scattering cross section below 10−40 cm2. We compare dark kinetic heating rates of other lower escape velocity objects such as the Earth, Sun, and white dwarfs, finding complementary kinetic heating signals are possible depending on particle physics parameters.

Comments: 24 pages, 11 figures
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); High Energy Physics – Phenomenology (hep-ph)
Report number: SLAC-PUB-17771
Cite as: arXiv:2405.02393 [astro-ph.EP] (or arXiv:2405.02393v1 [astro-ph.EP] for this version)
Submission history
From: Aidan Reilly
[v1] Fri, 3 May 2024 18:00:01 UTC (1,480 KB)

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