Our First Discoveries

It’s only 23 days since launch.  And you’ve already discovered stuff!

We are still working on interpreting your classification clicks, and we probably will be for many months to come.  But people have already submitted more than 1100 interesting subjects using the Think-You’ve-Got-One form, which is a bit easier for us on the science team to use right away.  Among these objects, science team member Adam Schneider quickly spotted at least three interesting ones that we’ll want to include in an upcoming paper.  Let me tell you about them.

This one has got the science team all abuzz.

TdwarfCandidate_animation

It’s either a fast dipole or a slow mover.  It mover about 1.25 pixels between the first and last epochs.  And it’s faint.  Faint is good!  That means it’s less likely to already have been discovered.

It’s a little red (maybe pink)  in color, meaning it’s significantly brighter in the WISE 2 band than in the WISE 1 band.  In  fact, if you look at how bright it is in the WISE 1 and WISE 2 bands, and the fact that it doesn’t appear in the 2MASS catalog at all,  you would infer that it is likely to be a kind of brown dwarf called a “T dwarf”.  If it is a T dwarf, it is about 30 parsecs (98 light years) away.   PLEASE FIND MORE OF THESE!!

We are trying right now to find someone who is at the right telescope at the right time to take a spectrum of it, which would confirm that it really is a T dwarf.  A colleague offered to observe it for us this week using NASA’s Infrared Telescope Facility. Alas, the weather was bad, and they didn’t even open the observatory dome. There are some opportunities coming up for us to get a spectrum from other telescopes in Hawaii.  We will keep you posted.

The next two new discoveries appear to be nearby M dwarfs, based on their WISE and 2MASS colors.  Nearby M dwarfs like these should make good targets for future exoplanet searches with the Transiting Exoplanet Survey Satellite (TESS)  and near infrared spectrographs like SPIREou, iLocator, and the Habitable Zone Planet Finder.

Take a peek at this subject.  At R.A. 11.8858634 degrees, declination -34.5458256 degrees (halfway up, near the left edge) is a blue-white dipole that appears to be a previously undiscovered M dwarf.  This flipbook is a bit tricky, since if you only looked at frame 1, for example, you might think it were covered with dipoles!  But when you play the animation, it becomes clear that most of those sources are ordinary artifacts.  Thanks to @raychieng for submitting it.

Finally, check out this subject.  Near the top, slightly left of center, at R.A. 217.8208564 degrees, declination 86.2991835 degrees (it’s almost at the north pole), is a moderately bright white dipole, which also appears to be a previously unreported M dwarf.   A VizieR search turns up a high-proper motion source at those coordinates in the PPMXL catalog and the URAT1 catalog, but without a spectral type. However, the photometry (i.e. how bright the star is, in magnitudes) across the suggests that this star is probably an M dwarf. Thanks to @stevnbak for submitting it.

How can you tell the spectral type of an object from its photometry? How can you recognize if your dipole/mover is an earth shattering new Y dwarf, a dazzling new T dwarf, a cool new M dwarf, or just a boring old early-type star? Stay tuned–we’ll talk about that in the next blog post.

Great work, everybody!   These discoveries are the proof of concept that we were hoping for.  And I’m sure there will be more to come.

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Brown Dwarf: The object you should start to love…

 

You probably didn’t realize it, but when you started classifying on BackyardWorlds.org you were actually helping us search the nearby solar neighborhood for cold hidden worlds called brown dwarfs.  You might be asking yourself “Brown what”? And I’m here to answer that!  Lets start from the beginning.  Here is a cartoon version of star formation (on the left) and brown dwarf formation (on the right).  They form the same way!  The ingredients are a cloud of Hydrogen and Helium that collapses, fragments and then ignites.  Now the difference is that the star can ignite nuclear fusion.  The brown dwarf isn’t massive enough to get the core hot enough for that to happen.  So instead of having a nuclear engine that sustains its brightness for millions or billions of years like stars do, brown dwarfs just cool off for their entire lives.  BD_formation_watermark.jpg

Want to know another kind of object that cools for the entirety of its existence?  A planet.  So I like to say that brown dwarfs are objects that form like stars but evolve like planets.

Now brown dwarfs have temperatures so low that the majority of their light doesn’t come out in visible light.  While we now know that they are ABUNDANT in the Milky Way Galaxy, if you look up in the nighttime sky not a single one of those several thousand points of light you see is a brown dwarf.  They are invisible to human perception.  In order to find them we must turn to longer wavelength light.  Brown dwarfs glow in the infrared.  Thats why the NASA data we are using from the Wide-Field Infrared Survey Explorer (or WISE for short) is so critical to brown dwarf science.  WISE has scanned the entire sky in the infrared and given us an unprecedented search tool for cold brown dwarfs near the Sun.  In fact the WISE telescope was designed in part to be able to find the coldest types of these objects.

Brown dwarfs come in three types of “flavors”.  There are L types, T types and Y types.  See the image below for some details on the temperatures of these types.BDs.001.jpgThe L types are the warmest and the Y types are the coldest.  Arguments could be made for which kind of brown dwarf is the most exciting to study but for the sake of this blog post I’ll tell you about two different ones that were stupendous discoveries to come out of mining WISE data the same way that you are doing.

Just a few years ago an Astronomer from Penn State named Kevin Luhman was looking through the WISE data for objects that moved over the full timeline of the spacecraft.  In 2013 he discovered a fantastic brown dwarf binary (named Luhman16AB after him) that turned out to be the 3rd closest system to the Sun.  Until that time Astronomers figured they had the solar neighborhood solidified.  The last time the top 5 closest objects to the Sun had changed was almost a century prior.  More than that, Luhman16AB is a dynamic system.  One of the objects is an L type and one is a T type.  The L type appears to have large violent storms raging in the outer atmosphere.  Astronomers have made maps of it and are using it to understand what exoplanet weather might look like.  This binary had been missed by numerous professional and very experienced astronomers (myself included) because it moves very fast and is in a particularly crowded part of the sky.  By blinking images you might be able to uncover another bright, beautiful system like this one.

BDs.002.jpg
An artists rendition of what a brown dwarf with active storms and weather might look like.

The second object I want to tell you about is one of the most exciting discoveries I’ve seen in my career as a brown dwarf scientist.  Its an object called WISE0855 and its a Y type brown dwarf with a mass between 3 – 10 times that of Jupiter and a surface temperature equivalent to a balmy day at the North Pole.  Dr. Luhman also found this one by blinking images and it turns out to be the coldest compact source ever discovered outside our own solar system.  It’s so cold that its outer atmosphere is likely teeming with water ice clouds.  In 2014 I wrote a paper on the indications of those water clouds in the object and in 2016 I worked with a team that obtained the very first spectrum of it.  We  directly compared it to Jupiter and found striking similarities.  Best of all, WISE0855 is the 4th closest system to the Sun.  Just a bit further than Luhman16AB.  In just one year, WISE data completely changed the solar neighborhood.  This should make you wonder, what else is out there?  With so many eyes working on the WISE dataset I’m hoping we pinpoint a brown dwarf that is closer than proxima centauri (the closest star).  One that is covered in strange exotic clouds.  Hopefully one of our thousands of volunteers is blinking an image right now and marking a key object in understanding the atmospheres of worlds beyond our solar system.

Good Luck Searching!  — Jackie