Hubble image archive
Hubble Observations Used to Measure Mass of Lone White Dwarf Star LAWD 37
This graphic shows how microlensing was used to measure the mass of a white dwarf star. The dwarf, called LAWD 37, is a burned-out star in the center of this Hubble Space Telescope image. Though its nuclear fusion furnace has shut down, trapped heat is sizzling on the surface at...
- Date
- Jan 1, 2023
- Mission
- Hubble Space Telescope
- Archive ID
- hubblesite-images-2023-004-01gqqse7e2hqkgt8tpafc5e0qh
This graphic shows how microlensing was used to measure the mass of a white dwarf star.
The dwarf, called LAWD 37, is a burned-out star in the center of this Hubble Space Telescope image. Though its nuclear fusion furnace has shut down, trapped heat is sizzling on the surface at 180,000 degrees Fahrenheit, causing the stellar remnant to glow fiercely.
The inset box plots how the dwarf passed in front of a background star in 2019. The wavy blue line traces the dwarf's apparent motion across the sky as seen from Earth. Though the dwarf is following a straight trajectory, the motion of Earth orbiting the Sun imparts an apparent sinusoidal offset due to parallax. (The star is only 15 light-years away. Therefore, it is moving at a faster rate against the stellar background.)
As it passed by the fainter background star, the dwarf's gravitation field warped space (as Einstein's theory of general relativity predicted a century ago). And this deflection was precisely measured by Hubble's extraordinary resolution. The amount of deflection yields a mass for the white dwarf of 56 percent our Sun's mass and provides insights into theories of the structure and composition of white dwarfs. This is the first time astronomers directly measured the mass of a single, isolated white dwarf star, thanks to a "funhouse mirror" trick of nature.
Credits
Science
NASA, ESA, Peter McGill (UC Santa Cruz, IoA), Kailash Sahu (STScI)
Image Processing
Joseph DePasquale (STScI)
Image Details
| About The Object | |
|---|---|
| Object Name | LAWD 37 (LP 145-141) |
| Object Description | Isolated White Dwarf |
| R.A. Position | 11:45:42.9205 |
| Dec. Position | -64:50:29.459 |
| Constellation | Musca |
| Distance | About 15 light-years |
| Dimensions | Image is 1.2 arcmin across (about 0.005 light-years) |
| About The Data | |
| Data Description | This image was created with Hubble data from proposals: , , and (K. Sahu). |
| Instrument | WFC3/UVIS |
| Exposure Dates | 9 pointings between May 2019 and Sep 2020 |
| Filters | F555W, F814W |
| About The Image | |
| Color Info | These images are a composite of separate exposures acquired by the Hubble Space Telescope using the WFC3/UVIS instrument. Several filters were used to sample specific wavelength ranges. The color results from assigning different hues (colors) to each monochromatic (grayscale) image associated with an individual filter. In this case, the assigned colors are: Cyan: F555W, Orange: F814W |
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Image and source material are credited to the official mission archive linked below.
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