WASP-104b is Darker than Charcoal
By analysing the K2 short-cadence data from Campaign 14 we detect phase-curve modulation in the light curve of the hot-Jupiter host star WASP-104. The ellipsoidal modulation is detected with high significance and in agreement with theoretical expectations, while Doppler beaming and reflection modulations are detected tentatively. We show that the visual geometric albedo is lower than 0.03 at 95% confidence, making it one of the least-reflective planets found to date. The light curve also exhibits a rotational modulation, implying a stellar rotational period likely to be near 23 or 46 days. In addition, we refine the system parameters and place tight upper limits for transit timing and duration variations, starspot occultation events, and additional transiting planets.
WASP-104b's albedo was previously thought to be 0.4 (absorbing 60% of incoming light).
Also at ScienceAlert.
Related: NASA Finds a Pitch-Black Hot Jupiter Exoplanet (WASP-12b)
(Score: 2) by Immerman on Thursday April 26 2018, @03:47AM
Hmm, at roughly the same density as Jupiter I would assume it would have to be mostly hydrogen as well. Presumably "hot" is one of the defining features, so that a much wider range of materials can remain gaseous, even in the visible upper atmosphere.
Or, just to make things more fun, maybe the planet simply hosts a thriving population of high-efficiency atmospheric photovores. Or it may not even be a gas giant, but rather a civilization that has built a dense array of efficient orbital solar collectors, leaving a much smaller, denser planet completely hidden within it. Perhaps even a previously super-Jupiter Chthionian world, rich in "exotic" minerals formed under the intense heat and pressures the atmosphere once provided.