The University of Utah
Department of Physics & Astronomy at the University of Utah

Nearest Bright ‘Hypervelocity Star’ Found

Speeding at 1 Million mph, It Probes Black Hole and Dark Matter


An astrophysicist-artist's conception of a hypervelocity star speeding away from the visible part of a spiral galaxy like our Milky Way and into the invisible halo of mysterious "dark matter" that surrounds the galaxy's visible portions. University of Utah researcher Zheng Zheng and colleagues in the U.S. and China discovered the closest bright hypervelocity star yet found. Photo Credit: Ben Bromley, University of Utah

May 7, 2014 – A University of Utah-led team discovered a “hypervelocity star” that is the closest, second-brightest and among the largest of 20 found so far. Speeding at more than 1 million mph, the star may provide clues about the supermassive black hole at the center of our Milky Way and the halo of mysterious “dark matter” surrounding the galaxy, astronomers say.

“The hypervelocity star tells us a lot about our galaxy – especially its center and the dark matter halo,” says Zheng Zheng, an assistant professor of physics and astronomy and lead author of the study published recently in Astrophysical Journal Letters by a team of U.S. and Chinese astronomers.

“We can’t see the dark matter halo, but its gravity acts on the star,” Zheng says. “We gain insight from the star’s trajectory and velocity, which are affected by gravity from different parts of our galaxy.”

In the past decade, astronomers have found about 20 of these odd stars. Hypervelocity stars appear to be remaining pairs of binary stars that once orbited each other and got too close to the supermassive black hole at the galaxy’s center. Intense gravity from the black hole – which has the mass of 4 million stars like our sun – captures one star so it orbits the hole closely, and slingshots the other on a trajectory headed beyond the galaxy.


Zheng Zheng, an assistant professor of physics and astronomy at the University of Utah, led a team of American and Chinese scientists who discovered the closest bright hypervelocity star of 20 yet found. Scientists believe each hypervelocity star began as part of a binary pair of stars near the center of our Milky Way galaxy, where extreme gravity from a supermassive black hole sucked in one star in the pair and, like a bolo, simultaneously hurled the other star -- a new hypervelocity star -- toward the edge of the galaxy. Photo Credit: Lee J. Siegel, University of Utah

Zheng and his colleagues discovered the new hypervelocity star while conducting other research into stars with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope, or LAMOST, located at the Xinglong Observing Station of the National Astronomical Observatories of China, about 110 miles northeast of Beijing.

LAMOST boasts a 13.1-foot-wide aperture and houses 4,000 optical fibers, which capture “spectra” or light-wavelength readings from as many as 4,000 stars at once. A star’s spectrum reveals information about its velocity, temperature, luminosity and size.

LAMOST’s main purpose is to study the distribution of stars in the Milky Way, and thus the galaxy’s structure. The new hypervelocity star – named LAMOST-HVS1 – stood out because its speed is almost three times the usual star’s 500,000-mph pace through space: 1.4 million mph relative to our solar system. Its speed is about 1.1 million mph relative to the speed of the center of the Milky Way.

Despite being the closest hypervelocity star, it nonetheless is 249 quadrillion miles from Earth. (In U.S. usage, a quadrillion is 1,000,000,000,000,000 miles or 10 to the 15th power, or 1 million billion).

“If you’re looking at a herd of cows, and one starts going 60 mph, that’s telling you something important,” says Ben Bromley, a University of Utah physics and astronomy professor who was not involved with Zheng’s study. “You may not know at first what that is. But for hypervelocity stars, one of their mysteries is where they come from – and the massive black hole in our galaxy is implicated.”

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Astronomy Week


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Monday, May 5:
Telescopes in the Park, Solar Observing at Liberty Park,
Noon - 4:00 pm

Join the University of Utah's AstronomUr Outreach Group at Liberty Park to view the Sun through specialized telescopes! Learn more...

Tuesday, May 6:
Sidewalk Solar Observing Party, Downtown City Library
Noon - 4:00 pm

Think star-gazing is only possible at night? Think again! Join us at the City Library in downtown Salt Lake for solar observing. Learn more...

Wednesday, May 7:
Star Party & Solar Observing at the South Physics Observatory 
6:00 pm - 11:00 pm

Let our observatory guides take you on a tour of the night sky! Learn more...

Thursday, May 8:
Film Festival with Topical Discussions, 408 South Physics Building, University of Utah
6:00 pm - 8:00 pm

Join our AstronomUrs in a cosmic journey Hollywood-style and learn why space is so hard to replicate on the big screen! Learn more...

Friday, May 9:
Star Party at the South Physics Observatory, University of Utah
8:00 pm - Midnight

Come explore astronomy through one of our 14 telescopes and learn how astronomers make discoveries! Learn more...

Saturday, May 10:
Astronomy Activities at the Natural History Museum of Utah,
Noon - 4:00 pm

Learn more about telescopes and how astronomers make discoveries with a variety of presentations and activities! Learn more...

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2014 Graduation Awards & Scholarships

Graduation and commencement exercises for the University of Utah took place on May 1-2, 2014. The Department of Physics & Astronomy congratulates all of its 2014 graduates and welcomes them to their alumni family.


Anne Marie Schaeffer

Weili Hong

Uyen Huynh

Hans Malissa

Dali Sun

Christopher Ahn

Ian Sohl

Joshua Wallace

Rachel Baarda

Alissa Whiting

Julie Imig

Ethan Lake

Congratulations to our 2014 graduates and scholarship recipients!

2014 Awards & ScholarshipsBaccalaureate DegreesMasters DegreesPh. D Degrees

Swigart Scholarship for Outstanding Graduate Student
Anne Marie Schaeffer
Weili Hong
Henrik Odeen

Outstanding Graduate Student
Mark Limes
Uyen Huynh

Outstanding Postdoctoral Research
Hans Malissa
Dali Sun

Outstanding Graduate Teaching Assistants
Chris Ahn
Janivda Rou

Outstanding Undergraduate Teaching Assistants
James Skowronek

Paul Gilbert Outstanding Undergraduate Research
Joshua Wallace

Martin Hiatt Outstanding Undergraduate Research
Rachel Baarda

Outstanding Undergraduate - Senior
Leslie Mershon

Outstanding Undergraduate - Junior
Trey Jensen

Outstanding Undergraduate - Sophomore
Alissa Whiting

Walter Wada Memorial Award
Julie Imig

Tyler Soelberg Memorial Award
Josh Hanes

Parmley Award
Ian Sohl

Departmental Scholarship
Christopher Harker
Trey Jensen
Ethan Lake
David Stephens

Rachel Baards – HBS
Kouver Bingham – HBS
Matthew Byrne
Zachary Carson
Andrew Dilts
Parker Duncan
Tristan Ellsworth
Mohamed Elsherif – Physics Teaching
Anthony Garcia - HBS
Chris Ginzton – BA
Nathan Gygi
Laurel Hales - HBS
Nino Hodzic
Erik Houghtby
Matthew Hunsaker
Natascha Knowlton
Austin Lee
Kayla Martindale
Shawn Merrill
Quinton Nethercott
Jeff Palmer
Evangelia Papadopoulos – HBS
Tyler Schmauch
Justin Talbot
Scott Temple
Sean Vetsch
Joshua Wallace – HBS
Matthew Wallace
Joshua Wolfe
Veronika Burobina
Michael Doleac – Physics Teaching
David Harris
Brendan Pankovich
Pei-i-Ku
Weili Hong
Mark Limes
Robert Roundy
Yiping Shu
Xuefang Sui
Alex Thiessen
David Waters
Rhett Zollinger

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2014 Graduation Reception

From the Office of the Registrar

"The University of Utah commencement and convocation ceremonies are held annually at the conclusion of spring semester. Candidates for graduation in the summer 2013, fall 2013, spring 2014, or summer 2014 terms may attend. University Commencement will be held on Thursday, May 1, 2014 at 6:30pm in the Jon M Huntsman Center (Map). For more information, please visit the Commencement Ceremony page.

Commencement and Convocation Ceremonies are open to the public and free to attend. No tickets or RSVP required. Those who are unable to attend commencement will be able to watch the live stream via the utah.edu website, watch the rebroadcast on KUED Channel 7."

Each college holds a convocation ceremony, where students are acknowledged individually by degree. For the College of Science Convocation Ceremony, this will take place at 3:30pm on Friday May 2, 2014 at Kingsbury Hall. (Map)

Each department holds a graduation reception, where student achievements and scholarships are presented. For the Department of Physics & Astronomy Graduation Reception, this will take place at 1:00pm on Friday May 2, 2014 in the Rotunda of the James Fletcher Building. (Map)

To learn more, please visit the Commencement Ceremony page.

Graduation Events & Ceremonies

University of Utah
Commencement

Thurs., May 1, 2014
6:30pm
Jon M Huntsman Center
(Map)
Dept of Physics & Astronomy
Graduation Reception

Fri., May 2, 2014
1:00pm
Rotunda - James Fletcher Bldg
(Map)
College of Science
Convocation Ceremony

Fri., May 2, 2014
3:30 pm
Kingsbury Hall
(Map)

 

Parking & Transportation
Campus parking lots may be used at no charge during commencement and convocation ceremonies. Please see our commencement parking map for parking locations as well as shuttle and TRAX stops. Additionally, since campus parking is limited, we encourage the use of UTA on these days. The use of UTA while on campus is free both days, but fare is still required for any off campus travel.

To learn more, please visit the Commencement Ceremony Parking & Transportation page.

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