Einsteins theory of general relatively changed the way scientists look at the universe. The presence of mass bends spacetime like a bowling ball depressing a mattress, causing light to curve as it travels through these depressions on its way to Earth. In 1919, Sir Arthur Eddington confirmed this effect by measuring the deflection of background stars caused by our Sun during a total solar eclipse. Nearly a century later, astronomers have used the Hubble Space Telescope (HST) to measure this effect caused by a star outside our solar system for the first time.
This groundbreaking result was announced today at the 230th Meeting of the American Astronomical Society by Kailash Sahu of the Space Telescope Science Institute. Sahus team used HST to capture the deflection of light from a background star as a white dwarf, the remnant core of a star once like our Sun, passed in front of it as seen from Earth. Although this deflection was tiny about 1,000 times smaller than the deflection measured by Eddington in 1919 the precision achievable with Hubble allowed astronomers to see it clearly. From the deflection, they were able to measure the mass of the white dwarf, called Stein 2051B, in a new way that independently confirms the theoretical mass-radius relationship for white dwarfs. This is good news, because the mass-radius relationship is the foundation for astronomers use of these objects as standard distance indicators in cosmology. The work will appear this month in the journal Science.
To find a suitable pair of stars to accomplish this task, Sahus team first combed through a catalog of 10,000 stars with large proper motions, or movements on the sky as seen from Earth. Based on the motions of these stars, the team projected the stars positions forward in time to find a pair that would pass close enough to each other (when projected on the sky, not in physical space) to produce a bend in starlight measurable with HST.
Their choice: Stein 2051B, a white dwarf 17 light-years from Earth. According to the teams calculations, Stein 2051B would pass in front of a distant background star, about 5,000 light-years away, causing the background starlight to bend by 2 milliarcseconds. In more understandable terms, seeing that bend would be like trying to watch an insect crawl across the face of a quarter from a distance of about 1,500 miles (2,400km).
The team enlisted Hubble to observe the stars over eight epochs, or points in time, with observations taken in the time leading up to, during, and after the event, which occurred in March 2014. And, indeed, they did observe a deflection of the background light as the white dwarf passed in front of the distant source.
This work represents two firsts in astronomy. One, its the first time a deflection due to general relativity has been measured using a star other than our Sun. And two, as Sahu explained during the press conference, measuring the mass of Stein 2051B is the first clean test for [the] mass-radius relationship.
The mass-radius relationship for white dwarfs leads to a limit called the Chandrasekhar limit. If a white dwarf accumulates mass past this limit (by stealing it off a binary companion), it will explode as a supernova, which can be seen from vast distances and can be used by astronomers to measure very large distances accurately. But if this relationship is different than we currently understand it, it would affect distance measurements based on white dwarf supernovae.
Read more from the original source:
Astronomers weigh a white dwarf using gravitational lensing - Astronomy Magazine
- I Spy With My Little Eye… - November 7th, 2009 [November 7th, 2009]
- A Crack Opens in the Ethiopian Landscape, Preparing the Way for a New Sea | 80beats - November 8th, 2009 [November 8th, 2009]
- The Politics of Addiction | The Intersection - November 8th, 2009 [November 8th, 2009]
- Finally! An iPhone App That Lets You Track Your Bathroom Habits | Discoblog - November 8th, 2009 [November 8th, 2009]
- Don’t Pack Your Bags Yet—New Planet-Finder Hobbled by Electronic Glitch | 80beats - November 8th, 2009 [November 8th, 2009]
- In Controversial Scent Lineups, a Dog’s Nose Picks Out the Perp | 80beats - November 8th, 2009 [November 8th, 2009]
- Are You a Cognitive Miser? | Cosmic Variance - November 8th, 2009 [November 8th, 2009]
- The Secret Lives and Loves of Great White Sharks | 80beats - November 8th, 2009 [November 8th, 2009]
- Britain’s New Protected Minority: Tree-Huggers | Discoblog - November 8th, 2009 [November 8th, 2009]
- Inspired by Maple Seeds, a Robotic Whirligig Takes To The Skies | Discoblog - November 8th, 2009 [November 8th, 2009]
- New Statesman on Accommodationism | The Intersection - November 8th, 2009 [November 8th, 2009]
- Laser-Powered Robot Climbs to Victory in the Space-Elevator Contest | 80beats - November 8th, 2009 [November 8th, 2009]
- Checking Back In With SEAPLEX | The Intersection - November 8th, 2009 [November 8th, 2009]
- Podcast: An Embarrassment of Genomes | The Loom - November 8th, 2009 [November 8th, 2009]
- A Baby Neutron Star, Swaddled in a Carbon Atmosphere | 80beats - November 8th, 2009 [November 8th, 2009]
- Butterfliiiies… iiinnnn… SPPPAAAAACCCCEEEEE! | Bad Astronomy - November 8th, 2009 [November 8th, 2009]
- My Slate Dialogue with Michael Specter Begins | The Intersection - November 8th, 2009 [November 8th, 2009]
- Musical, Fahrvergnügen-Inspired Staircase Makes Commuters Less Lazy | Discoblog - November 8th, 2009 [November 8th, 2009]
- Laser-Etched Fruit Is an Answer in Search of a Problem | Discoblog - November 8th, 2009 [November 8th, 2009]
- Ares and the carnivals | Bad Astronomy - November 8th, 2009 [November 8th, 2009]
- Toddler Gets a Telescoping, Prosthetic Arm Bone That Grows With Him | 80beats - November 8th, 2009 [November 8th, 2009]
- Neutered HIV Virus Delivers Treatment to Fatally Ill Boys | 80beats - November 8th, 2009 [November 8th, 2009]
- Specter’s First Reply: Denialism Kills People | The Intersection - November 8th, 2009 [November 8th, 2009]
- LRO sees a Moonslide | Bad Astronomy - November 8th, 2009 [November 8th, 2009]
- Al Gore’s New Book: A Focus on Solutions | The Intersection - November 8th, 2009 [November 8th, 2009]
- The Universe Has Us in Its Crosshairs | Bad Astronomy - November 8th, 2009 [November 8th, 2009]
- Makers of Universes | Cosmic Variance - November 8th, 2009 [November 8th, 2009]
- Can Your Pet Catch & Spread Swine Flu? Yes, If Your Pet’s a Ferret | 80beats - November 8th, 2009 [November 8th, 2009]
- Droid 2.0 Vs iPhone | The Intersection - November 8th, 2009 [November 8th, 2009]
- Tangled Bank News: An Excerpt and More | The Loom - November 8th, 2009 [November 8th, 2009]
- LHC Shut Down By Wayward Baguette, Dropped by Bird Saboteur | Discoblog - November 8th, 2009 [November 8th, 2009]
- Careidolia | Bad Astronomy - November 8th, 2009 [November 8th, 2009]
- Slate Reply to Specter Up–We Need a National Dialogue on Synthetic Biology | The Intersection - November 8th, 2009 [November 8th, 2009]
- Pray this doesn’t get passed | Bad Astronomy - November 8th, 2009 [November 8th, 2009]
- You Can’t Make This Stuff Up | Cosmic Variance - November 8th, 2009 [November 8th, 2009]
- Mother Tongue, Indeed: Newborn’s Cries Mimic Mama’s Accent | 80beats - November 8th, 2009 [November 8th, 2009]
- Ripped From the Journals: The Biggest Discoveries of the Week | 80beats - November 8th, 2009 [November 8th, 2009]
- Alternative Landscapes | The Loom - November 8th, 2009 [November 8th, 2009]
- Can an iPhone App Decipher Your Baby’s Cries? | Discoblog - November 8th, 2009 [November 8th, 2009]
- Reminder: Carl Sagan Day | Bad Astronomy - November 8th, 2009 [November 8th, 2009]
- Are There Pesticides in Your Soup? Dunk a Pollution Dipstick to Find Out. | 80beats - November 8th, 2009 [November 8th, 2009]
- Log in and Join the Conference - November 8th, 2009 [November 8th, 2009]
- Conference Ends - November 8th, 2009 [November 8th, 2009]
- Conference Archive Opens - November 8th, 2009 [November 8th, 2009]
- Galaxy Zoo - November 8th, 2009 [November 8th, 2009]
- .Astronomy 2009 Dates - November 8th, 2009 [November 8th, 2009]
- .Astronomy 2009: Programme and venue details - November 8th, 2009 [November 8th, 2009]
- .Astronomy Gets Some IYA Love - November 8th, 2009 [November 8th, 2009]
- 2009 Posters and Imagery - November 8th, 2009 [November 8th, 2009]
- 2009 Sponsors - November 8th, 2009 [November 8th, 2009]
- When in Holland… - November 8th, 2009 [November 8th, 2009]
- The WHAT Cloud? - November 8th, 2009 [November 8th, 2009]
- The Jewel Box - November 8th, 2009 [November 8th, 2009]
- Happy Halloween! - November 8th, 2009 [November 8th, 2009]
- Ares 1-X Launch - November 8th, 2009 [November 8th, 2009]
- Confessions of an Alien Hunter - November 8th, 2009 [November 8th, 2009]
- LRO Spies Apollo 17 Site - November 8th, 2009 [November 8th, 2009]
- Mercury in Color - November 8th, 2009 [November 8th, 2009]
- Hubble and M83 - November 8th, 2009 [November 8th, 2009]
- Cassini Flyby of Enceladus - November 8th, 2009 [November 8th, 2009]
- Preserving A Moth [Science Tattoo] | The Loom - December 12th, 2009 [December 12th, 2009]
- Another Russian rocket spiral lights up the sky | Bad Astronomy - December 12th, 2009 [December 12th, 2009]
- A (Very Gentle) Riddle to Complete Your Saturday - December 12th, 2009 [December 12th, 2009]
- Darwin Gets Swine Flu: The YouTube Edition | The Loom - December 12th, 2009 [December 12th, 2009]
- Happy Slothy Holidays | The Loom - December 12th, 2009 [December 12th, 2009]
- Jetting to Copenhagen | The Intersection - December 12th, 2009 [December 12th, 2009]
- Michael Gerson Attempts Thoughtfulness on “ClimateGate,” Then Gives it Up | The Intersection - December 13th, 2009 [December 13th, 2009]
- Incredible VISTA of the cosmos | Bad Astronomy - December 13th, 2009 [December 13th, 2009]
- Bundle up Sunday Night to Watch the Geminid Meteor Shower | 80beats - December 13th, 2009 [December 13th, 2009]
- “ClimateGate” a PR Disaster That Will Be “Taught in University Communications Courses” | The Intersection - December 13th, 2009 [December 13th, 2009]
- Is Google the Guardian Angel of Rainforests? | 80beats - December 13th, 2009 [December 13th, 2009]
- La ciencia es importante. Una vez mas. | Bad Astronomy - December 13th, 2009 [December 13th, 2009]
- Sensenbrenner Pulls an Inhofe, Asserts Global Warming is an “International Conspiracy” | The Intersection - December 13th, 2009 [December 13th, 2009]
- Let Kids Eat Dirt: Over-Cleanliness Linked to Heart Disease | 80beats - December 13th, 2009 [December 13th, 2009]
- What Are The Best Science Papers Of The Past Decade? | The Intersection - December 13th, 2009 [December 13th, 2009]
- Finally! Math Shows How to Cut Evenly Sized Pizza Slices | Discoblog - December 13th, 2009 [December 13th, 2009]
- Half-baked math | Bad Astronomy - December 13th, 2009 [December 13th, 2009]
- Can “Biological Passports” Save Sports From Doping? | 80beats - December 13th, 2009 [December 13th, 2009]
- Aiiiieeee! Slow down! | Bad Astronomy - December 13th, 2009 [December 13th, 2009]
- Weekly News Roundup: Bad Headlines, Martian moons, and Rotating Houses | Discoblog - December 13th, 2009 [December 13th, 2009]