For the first time, a much younger version of the Sun has been caught red-handed blowing bubbles in the galaxy, by astronomers using NASA’s Chandra X-ray Observatory.
HD
61005 in X-ray, infrared, and optical light
These images
show the star HD 61005 with X-rays from the Chandra X-ray Observatory as well
as infrared data from Hubble Space Telescope. A view in optical light from a
telescope in Chile shows the larger field that HD 61005 is located in.
Astronomers recently used Chandra to discover an “astrosphere,” a wind-blown
bubble, around HD 61005, the first seen around a star like the Sun.
The bubble – called an “astrosphere” –
completely surrounds the juvenile star. Winds from the star’s surface are
blowing up the bubble and filling it with hot gas as it expands into much
cooler galactic gas and dust surrounding the star. The Sun has a similar bubble
around it, which scientists call the heliosphere, created by the solar wind. It
extends far beyond the planets in our solar system and protects Earth from
cosmic radiation.
This is the first image of an
astrosphere astronomers have obtained around a star similar to the Sun. It
shows slightly extended emission, rather than a single point of light as seen
for other such stars.
“We have 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 Astrophysical Journal. “This new Chandra result
about a similar star’s astrosphere teaches us about the shape of the Sun’s, 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 roughly the same mass and temperature as the Sun, but it is much younger
with an age of about 100 million years, compared to the Sun’s age of about 5
billion years.
Because it is so young, HD 61005 has a
much stronger wind of particles blowing from its surface that travels about 3
times faster and is about 25 times denser than the wind from the Sun. This
amplifies the process of astrosphere bubble-blowing and mimics how our Sun was
behaving several billion years ago.
HD 61005 in X-ray and Infrared light.
X-ray: NASA/CXC/John Hopkins Univ./C.M. Lisse et al.;
Infrared: NASA/ESA/STIS; Image Processing: NASA/CXC/SAO/N. Wolk
“We are impacted by the Sun every day,
not only through the light it gives off, but also by the wind it sends out 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 & Smithsonian (CfA). “This image of the astrosphere around HD 61005
gives us important information about what the Sun’s wind may have been like
early in its evolution.”
Astronomers have nicknamed the HD 61005
star system the “Moth” because it is surrounded by large amounts of dust
patterned similarly to the shape of a moth’s wings when viewed through infrared
telescopes. The wings are formed from material left behind after the formation
of the star, similar to the Kuiper Belt in our own solar system. Observations
of these wings with NASA’s Hubble Space Telescope showed 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 is producing
X-rays as the stellar wind runs into cooler local interstellar medium dust and
gas that surrounds the star. The dense local galactic environment, combined
with Chandra’s high-resolution X-ray vision, the strong stellar wind, and the
star’s proximity, all helped create a strong X-ray signal, allowing discovery
of an astrosphere around HD 61005. It has a diameter about 200 times the
distance from Earth to the Sun.
“There’s a saying about a moth being
drawn to a flame,” said co-author Brad Snios, formerly of CfA and now at MITRE,
a non-profit that participates in federally funded research. “In the case of HD
61005, the ‘Moth’ can’t easily escape from the flame because it was born around
it and might be sustained by a disk around it.”
An artist’s illustration depicts the astrosphere in
more detail, including a bow shock in blue — akin to a sonic boom in front of a
supersonic plane — that is caused by the motion of the star and its astrosphere
as it pushes against and flies through gas in interstellar space.
NASA/Goddard Space Flight Center, Conceptual Image Lab
The Sun not only likely passed through a
phase of development similar to HD 61005 when it was younger, it also likely
traveled through a denser region of dust and gas than where the Sun is
currently located, strengthening the connection with HD 61005.
“It is amazing to think that our
protective heliosphere would only extend out to the orbit of Saturn if we were
in the part of the galaxy where the Moth is located, or, conversely, that the
Moth would have an astrosphere 10 times wider larger than the Sun’s if it were
located here,” Lisse said.
HD 61005 is not visible from Earth with
the unaided eye, but it is close enough that skywatchers could see it using
binoculars.
The first hints of X-ray emission from
the Moth’s central star were based on a brief, one-hour-long Chandra
observation of HD 61005 in 2014. In 2021, astronomers observed HD 61005 for
almost 19 hours, which allowed 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: X-ray: NASA/CXC/John
Hopkins Univ./C.M. Lisse et al.; Infrared: NASA/ESA/STIS; Optical:
NSF/NoirLab/CTIO/DECaPS2; Image Processing: NASA/CXC/SAO/N. Wolk
To learn more about Chandra, visit: https://science.nasa.gov/chandra
Source: Young ‘Sun’ Caught Blowing Bubbles by NASA’s Chandra - NASA
