One Search To (Almost) Rule Them All: Hundreds of Hidden Planets Found in Kepler Data (scientificamerican.com) 39
Jonathan O'Callaghan, writing for Scientific American: Most of the more than 4,000 exoplanets astronomers have found across the past few decades come from NASA's pioneering Kepler mission, which launched in 2009 and ended in late October 2018. But among Kepler's cavalcade of data, more planets are still waiting to be found -- and a new method just turned up the biggest haul yet from the mission's second, concluding phase, called K2. The K2 run from 2014 to 2018 was notable for its unique use of the functionality, or lack thereof, of the Kepler space telescope. Essentially a large tube with a single camera, Kepler relied on four reaction wheels (spinning wheels to orient the spacecraft) to point at specific patches of the sky for days or even weeks on end. Such long stares were beneficial for its primary planet-finding technique, known as the transit method, which detects worlds by watching for dips in a star's light caused by an orbiting planet's passage in front of it. But when two of Kepler's reaction wheels failed, one in 2012 and another in 2013, mission planners came up with an ingenious method of using the pressure of the solar wind to act as a makeshift third wheel, allowing observations to continue, albeit with some limitations.
"We had this issue because the K2 mission was working off of two reaction wheels; it rolled a little bit every six hours," says Susan Mullally of the Space Telescope Science Institute. "And as a result, the light curves have these little arcs that run through them that you have to first remove." Various efforts were subsequently made to extract planets from the K2 data. But none have been more successful than one reported in a new paper by Ethan Kruse of NASA's Goddard Space Flight Center and his colleagues, which was posted on the preprint server arXiv.org last week and accepted for publication in the Astrophysical Journal Supplement Series. Kruse employed an algorithm known as as QATS (for Quasiperiodic Automated Transit Search) and a light-curve-analysis program called EVEREST (for EPIC Variability Extraction and Removal for Exoplanet Science Targets) to better account for the spacecraft's rolling and other sources of instrumental and astrophysical "noise" in the K2 data. The result was a whopping total of 818 planet candidates -- 374 of which had never been spotted before -- from the first nine of K2's 20 observation campaigns.
"We had this issue because the K2 mission was working off of two reaction wheels; it rolled a little bit every six hours," says Susan Mullally of the Space Telescope Science Institute. "And as a result, the light curves have these little arcs that run through them that you have to first remove." Various efforts were subsequently made to extract planets from the K2 data. But none have been more successful than one reported in a new paper by Ethan Kruse of NASA's Goddard Space Flight Center and his colleagues, which was posted on the preprint server arXiv.org last week and accepted for publication in the Astrophysical Journal Supplement Series. Kruse employed an algorithm known as as QATS (for Quasiperiodic Automated Transit Search) and a light-curve-analysis program called EVEREST (for EPIC Variability Extraction and Removal for Exoplanet Science Targets) to better account for the spacecraft's rolling and other sources of instrumental and astrophysical "noise" in the K2 data. The result was a whopping total of 818 planet candidates -- 374 of which had never been spotted before -- from the first nine of K2's 20 observation campaigns.
Time for Slashdot to start deleting posts again (Score:3, Insightful)
Do we really need to read this nutjob's manifesto multiple times in every story? He used to spam about hosts before really losing it. This guy is a mass shooting waiting to happen, and Slashdot should not be giving him a forum to post this nonsense. APK is becoming increasingly deranged and probably is actually a danger to society at this point.
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There's APK and then there's the APK impersonating spammer nazi who posts swastikas and tries to keep the Barbara feud alive, which... the dumbass Barbara (retired, 60? no) feeds right back into, constantly.
And thanks to the internet, they could all be the same person.
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Do we really need to read this nutjob's manifesto multiple times in every story?
Whoever is running Slashdot these days really is asleep at the wheel it seems, there's a lot of garbage noise that really needs to be cleaned out.
It's not like Slashdot posting frequency is so high that you couldn't even use some high-school intern to just clean out junk, or firewall AC posts (probably the only real solution).
I've always thought also you could probably do a pretty good job moderating by looking at people who fla
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There were times where scanning at the moderation hell, down there at -1 was sometimes interesting. Not that much anymore. Yes it got much worse recently, to the point that I wonder if I should open that page at work. Unfortunately.
OTOH most of the media these days, if at all open for comments, have their comments sections either full of abuse or delete whatever their moderators consider to be wrongthink which causes another problem of course.
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This ^^
Old(ish)-timer agreeing with you 100%. Not that I even check slashdot all that often anymore. But I'm guessing there's a few of us lurking around.
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I'm fairly new to /. and the comments section on most of these posts have been pretty horrible. Seems like a bunch of immature children or spam most of the time.
The content filter is your friend. If you don't want to read bullshit first of all don't post any. Second of all if you are given mod points use them wisely. Thirdly set your filter to at least 2+.
If it's a good discussion you will have a wealth of content above 3, and i rarely see stupid shit at that level.
Reaction wheels failing (Score:1)
Many craft have had problems with reaction wheels failing prematurely. Several theories were floated about the causes, but I've yet to see closure on causes and solutions. Until then, it's aliens, of course.
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If I recall correctly, a manufacturer of reaction wheels created some devices that did not last very long when in-service. Probably the "bad" ones have all now failed.
A recent study that blamed arcing in bearings (Score:1)
In space, electrical charges can build up in strange ways. And a reaction wheel bearings in zero-g operate at precisely zero load for long periods of time, floating on a layer of lubricant.
Apparently reaction wheels can build up a charge until they discharge through the lubrication film in the ball bearings, which leaves small pits. Rough spots in bearings quickly multiply and lead to failure.
Anyway, it claimed that switching to nonconductive ceramic balls killed the problem. (Normally, ceramic balls are
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Have they actually tested any in space for a few years? They may find different problems.
I suspect they'd need to add more shock absorption to the reaction unit or the craft itself to compensate.
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In space, electrical charges can build up in strange ways.
Is it possible to capture this charge in some way , capacitors maybe, then use it for some other purpose? I'm guessing you can't ground anything in space, given the absent of ground.
Mythical man month (Score:2)