New Hypervelocity Binary Star Challenges Dark Matter, Stellar Acceleration Models

W. M. Keck Observatory press release…

A team of astronomers at the Friedrich Alexander University led by Péter Németh has discovered a binary star moving nearly at the escape velocity of our galaxy. There are about two dozen so-called hypervelocity stars known to be escaping the galaxy. While all of them are single stars, PB3877 is the first wide binary star found to travel at such a high speed. Additionally, the results of the new study challenge the commonly accepted scenario that hypervelocity stars are accelerated by the supermassive black hole at the galactic center. The findings are being published in the Astrophysical Journal Letters today.

PB3877 Binary
PB3877 is a hyper-velocity wide binary star zooming through the outskirts of the Milky Way galaxy. This image shows its current location as well as our Sun.
The team, in collaboration with researchers from the California Institute of Technology, showed the binary cannot originate from the Galactic Center, and no other mechanism is known that is able to accelerate a wide binary to such a high velocity without disrupting it. They therefore hypothesized there must be a lot of dark matter to keep the star bound to the Milky Way galaxy; or the binary star, PB3877, could be an intruder that has been born in another galaxy and may or may not leave the Milky Way again.

PB3877 was first reported to be a hyper-velocity, hot compact star, when it was discovered form the Sloan Digital Sky-Survey (SDSS) data in 2011. New spectroscopic observations were done with the 10 meter Keck II telescope at W. M. Keck Observatory on Maunakea, Hawaii and with the 8.2 meter Very Large Telescope (VLT) of the European Southern Observatory (ESO) in Chile.Caltech astronomers Thomas Kupfer and Felix Fürst observed PB3877 with the ESI Instrument fitted on the Keck II telescope.

“When we looked at the new data, much to our surprise, we found weak absorption lines that could not come from the hot star,” Kupfer said. “The cool companion, just like the hot primary, shows a high radial velocity. Hence, the two stars form a binary system, which is the first hyper-velocity wide binary candidate.”

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A Brilliant Day

It was a rainbow sort of day.

Colorful Commute
A rainbow on the mist over the summit access road
I am not really the rainbow and unicorns sort of guy, I am a bit more prosaic than that. That does not mean I do not notice the beauty of the world around me. Even on this beautiful island there are days that stand out.

After a spell of Kona weather the trades were back with a vengeance, blowing hard. This moved the Waimea mist wall halfway to Waikoloa. The result? Rainbows around every corner.

The first in sunrise light over the Kohala, the second in the mist as the sunlight pierced the low clouds near the airport, more of a fogbow actually. Another in the mist at Puhakuloa along Saddle Road, another on the summit road where heavier raindrops produced a brilliant bow. That was just the morning drive to work, the afternoon produced another set of rainbows for a total of seven, not counting the one I saw twice I as I drove into and out of Waimea.

Yeah, it was a rainbow sort of day.

Some Blog Changes Coming

You may have noticed that DarkerView got hacked back in late March. Somehow malicious files were inserted that sent search traffic to various less than reputable websites, of course that means mostly sex sites. Sorry about that.

GyPSy in the Night
The 11″ NexStar GPS telescope, GyPSy set up at Ka’Ohe
Only search traffic was affected, those who went directly to the site saw the correct webpage, thus I did not notice right away as I use direct links. As a side note, getting hacked does result in a huge spike in traffic volume, that was the first sign. This sort of hack is apparently called conditional redirect hack, essentially borrowing a reputable website’s reputation with the search engines to send traffic towards certain websites.

As a result I have been tightening up security around here. Removing some old plugins, changing things around and checking for known vulnerabilities. One thing you will soon see is that the old theme will be replaced for an entirely new look for DarkerView.

The old theme is just that… old. Also probably insecure as there has been no maintenance on it in years. As I really do not know how the attacker got in I need to look to everything that could have been the weakness. Time to update the look and update the code to something that is modern and supported.

Fixing the Stairs

Some carpenter years ago thought that two nails would be enough to hold the stairs up.  They did, for a decade or two, but they would eventually fail when the stringer began to split around the nails.

Jacking the Stairs
Jacking the front stairs back into place for repair.
The stairs did not collapse, no one was hurt.  On the other hand they had sunk about an inch and felt decidedly unstable underfoot.  Another weekend project!

Remove the old nails to free everything up.  Use the 3.5 ton floor jack to push the stairs back into place.  An aluminum plate and wood glue to splice together the split stringer. Quite a few new bolts, not nails, to hold everything together.  A bit of 3/8″ threaded rod on the other stringer to secure it to a joist.  I think everything is secure, solid underfoot again.  I just need a little paint to cover over the new work.

Spot a Young Moon

At sunset this evening the Moon will be less than a day past new, about 20 hours old and only 0.7% illuminated. It is possible, if somewhat challenging, to spot this very thin crescent in the evening sky deep in the bright glow of sunset.

Young Moon
A very young moon over Waikoloa, this is only 26 hours after new, visible to the unaided eye as a sliver in the fading glow of sunset

This evening the Sun will set at 18:39 and the Moon will set at 19:21, about ten degrees behind the Sun. Thus a low and clear western horizon is a necessity for locating the Moon tonight. Optical aid will also be very useful, once the correct area is located the Moon can often easily be found by sweeping the area with binoculars. A small, rich field telescope with a field of several degrees across can also be used.

The effort is aided a bit by the presence of the bright planet Mercury in the sunset this evening. The planet will be seven degrees higher in the sky and just a bit north of the Moon. If you find Mercury at 19:00HST, the Moon will be 5 degrees below the planet and four degrees to the south in azimuth.

In several cultures with lunar calendars the spotting of a young crescent Moon like this marks the beginning of the month. Often Moon sightings are used to determine religious holidays and other important events of the year. It is also an good challenge to practice your observational skills. have fun!

Davis-Monthan Air Show 1993

Davis-Monthan AFB was my last duty station, I spent a year working the flight-line there. After I was out of the military we visited that flight-line again, this time for the annual 1993 “Lightning and Thunder” air show. A good day, with fun displays and a performance by the Thunderbirds…

Jupiter 27 March 2016

Another pass on Jupiter this evening, the string of decent seeing nights has continued. I am working on improving the setup and my technique. I had been using a diagonal to mount the camera… That is gone. I futzed with the collimation a bit, but it really is quite close. I need to figure out how to get a barlow into this arrangement, do they make a rear cell thread barlow like the focal reducer?

The seeing really does appear to be my greatest limitation. Planning a trip to better seeing in the next couple weeks.

It is not an Easter egg, but this will have to do, the closest I have for the day…

Jove 20160327
Jupiter on March 27th, 2016. Celestron 11″ and a Canon 60D @ f/10