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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 JoeMerchant on Wednesday April 25 2018, @07:42PM (5 children)
Funny, when taking a photo of the moon you set the camera to normal daylight settings to get correct exposure of the moon's surface - would seem to say that the moon's surface is just about as reflective as normal terrestrial subjects.
As for this study, albedo of 0.03 - varying? Sounds like somebody miscalculated somewhere. Not saying impossible, in all the universe I'm sure there's a hot Jupiter somewhere with an albedo lower than 0.01, but did we find it in the local neighborhood? More likely a miscalculation.
Of course, there's the example of the early Mars camera color calibrations that tried to make the sky blue until they figured out that the insulation on some wires they were looking at was all the wrong color. Seems like that would be a good reason for future missions to carry some color calibration targets for the camera.
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(Score: 3, Informative) by takyon on Wednesday April 25 2018, @07:58PM (1 child)
https://www.sciencealert.com/hot-jupiter-wasp-104b-one-of-the-darkest-planets-ever [sciencealert.com]
Arxiv:
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 2) by JoeMerchant on Wednesday April 25 2018, @09:32PM
95% confidence has just as much meaning as the methods behind it. These guys are guessing, they are guessing better than anyone else on the planet could guess, but they have such a limited amount of data collected in such a novel way that there's not even a good absurd analogy about determining the eye color of a fruit fly on the other side of a football stadium with nothing but your 20-200 eyesight and three mirrors.
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(Score: 3, Interesting) by Kromagv0 on Wednesday April 25 2018, @08:12PM (1 child)
Actually the proper exposure rule for the moon is not the sunny 16 rule [wikipedia.org] (set the f stop to f/16 and the shutter speed to the reciprocal of the ISO) but is instead the looney 11 rule [wikipedia.org] where instead you set the f stop to f/11 and the shutter speed to the reciprocal of the ISO. So basically treat the moon as one stop darker than a regular sunny day. If you are shooting through haze or light clouds you may want to use f/8 instead.
T-Shirts and bumper stickers [zazzle.com] to offend someone
(Score: 2) by JoeMerchant on Friday April 27 2018, @04:50PM
First time I've heard of Looney 11 - back in the days of chemical film I think Sunny 16 was "good enough" for both cases. Plus, each chemical trial cost about $1 per photo to test, so several million times more than a digital photo costs today, I'd bet Looney 11 is based on research with much higher sample sizes.
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(Score: 2) by Immerman on Friday April 27 2018, @04:31PM
It may be as dark as coal, but the light side is still always brightly lit by high-noon intensity sunlight.