Young ‘Sun’ Caught Blowing Bubbles by NASA’s Chandra
For the first time, a much younger version of the Sun has been captured bubbling in the galaxy, by astronomers using NASA’s Chandra X-ray Observatory.
The bubble – called the “astrosphere” – completely surrounds the juvenile star. Winds from the star’s surface burst the bubble and fill it with hot gas as it expands into much colder galactic gas and dust surrounding the star. The Sun is surrounded by a similar bubble, which scientists call the heliosphere, created by the solar wind. It extends far beyond the planets of our solar system and protects Earth from cosmic radiation.
This is the first image of an astrosphere obtained by astronomers around a star similar to the Sun. It shows slightly extended emission, rather than a single point of light as seen for other similar stars.
“We’ve been studying our Sun’s astrosphere for decades, but we can’t see it from the outside,” said Carey Lisse of Johns Hopkins University in Baltimore, who led the study, which published [day of week] in the Journal of Astrophysics. “This new result from Chandra on the astrosphere of a similar star tells us about the shape of the Sun and how it has changed over billions of years as the Sun evolves and moves through the galaxy.”
The star is called HD 61005 and is located about 120 light years from Earth, making it relatively close. HD 61005 has about the same mass and temperature as the Sun, but it is much younger, with an age of about 100 million years, compared to the age of the Sun, which is about 5 billion years.
Because it is so young, HD 61005 is subject to a much stronger particle wind blowing from its surface, which moves about 3 times faster and is about 25 times denser than the Sun’s wind. This amplifies the process of blowing bubbles from the astrosphere and mimics the behavior of our Sun several billion years ago.
“We are impacted by the Sun every day, not only by the light it emits, but also by the wind it sends into space that can affect our satellites and potentially astronauts traveling to the Moon or Mars,” said co-author Scott Wolk of the Center for Astrophysics | Harvard and Smithsonian (CfA). “This image of the astrosphere around HD 61005 gives us important information about what the Sun’s wind might have looked like early in its evolution.”
Astronomers have nicknamed the star system HD 61005 the “Moth” because it is surrounded by large amounts of dust whose pattern resembles the shape of a moth’s wings seen through infrared telescopes. The wings are formed from materials left after the star formed, similar to the Kuiper belt in our own solar system. Observations of these wings with NASA’s Hubble Space Telescope have shown that the interstellar matter surrounding HD 61005 is about a thousand times denser than that around the Sun.
Since the 1990s, astronomers have been trying to capture an image of an astrosphere around a Sun-like star. Chandra was able to detect the astrosphere around HD 61005 because it produces X-rays as the stellar wind moves toward dust and gas in the colder local interstellar medium surrounding the star. The dense local galactic environment, combined with Chandra’s high resolution
“There’s a saying that a moth is attracted to a flame,” said co-author Brad Snios, formerly of CfA and now at MITER, a nonprofit that participates in federally funded research. “In the case of HD 61005, the ‘Moth’ cannot easily escape the flame because it was born around it and could be supported by a disk surrounding it.”
Not only did the Sun likely go through a developmental phase similar to HD 61005 when it was younger, but it also likely passed through a denser region of dust and gas than where the Sun is now, strengthening the connection to HD 61005.
“It is astonishing to think that our protective heliosphere would only extend as far as Saturn’s orbit if we were in the part of the galaxy where the Butterfly is located, or, conversely, that the Butterfly would have an astrosphere 10 times larger than that of the Sun if it were located here,” Lisse said.
HD 61005 is not visible from Earth with the naked eye, but it is close enough that sky observers can see it using binoculars.
The first hints of X-ray emission from Moth’s central star were based on a brief one-hour Chandra observation of HD 61005 in 2014. In 2021, astronomers observed HD 61005 for nearly 19 hours, leading to the detection of the extended astrospheric structure.
NASA’s Marshall Space Flight Center manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.
Image credit: Radiography: NASA/CXC/John Hopkins Univ./CM Lisse et al. ; Infrared: NASA/ESA/STIS; Optics: NSF/NoirLab/CTIO/DECaPS2; Image processing: NASA/CXC/SAO/N. Wolf
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Learn more about NASA’s Chandra X-ray Observatory
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This release contains three main images, each offering a different view of the astrosphere surrounding a young star called HD 61005. An astrosphere is a wind-blown bubble, filled with gas and dust particles, that envelops a star as it moves through interstellar space.
In this version, an optical image from the Cerro Tololo Inter-American Observatory in Chile shows HD 61005 in the context of its star field. Here, the star in question appears as a bright white dot surrounded by other bright spots of similar and smaller sizes. The image is completely filled with points of light in shades of blue, white, gold, green and red. At this distance, during optical observation, the star’s astrosphere is not discernible.
The second image is a composite that shows a close-up of HD 61005 using infrared data from Hubble and X-ray data from the Chandra X-ray Observatory. Here, the spherical star has a bright core glowing with white X-ray light. The white core is surrounded by a neon purple glow; the astrosphere surrounding the star. A distinctive feature of HD 61005 is a white wedge-shaped tail with neon blue tips, which follows the fast-moving star. This tail is dusty material left after the star formed. The wedge or wing shape of the tail has earned the star the nickname “Butterfly” by astronomers who observe it using infrared telescopes.
The third image in this release is an artistic illustration of an astrosphere in action. Here, a large pale purple ball rises from our right to our left, in a hazy brown cloud. The purple ball appears to be protected by a blue force field, which repels the brown cloud as the ball dives. In this illustration, the purple ball represents the astrosphere surrounding a star and the brown cloud is interstellar gas. The blue force field is an arc shock, a curved, floating shock wave, similar to the sonic boom that travels in front of a supersonic aircraft. The arc shock is caused by the motion of the star and its astrosphere hurtling through space. This illustration shows a series of faint lines representing the wind patterns of HD 61005, but does not show the tail of debris found behind and to the side of HD 61005.
Megan Watzke
Chandra X-ray Center
Cambridge, Mass.
617-496-7998
mwatzke@cfa.harvard.edu
Joel Wallace
Marshall Space Flight Center, Huntsville, Alabama
256-544-0034
joel.w.wallace@nasa.gov
