Across The Universe, Cont. -- Sparkling Spiral And Flame Nebula

 

(click on images to enlarge)

From NASA/ ESA, March 10, 2025: This NASA/ESA Hubble Space Telescope Picture of the Week features a sparkling spiral galaxy paired with a prominent star, both in the constellation Virgo. While the galaxy and the star appear to be close to one another, even overlapping, they’re actually a great distance apart. The star, which is marked with four long diffraction spikes, is in our own galaxy. It’s just 7109 light-years away from Earth. The galaxy, which is named NGC 4900, lies about 45 million light-years from Earth.

This image combines data from two of Hubble’s instruments: the Advanced Camera for Surveys, which was installed in 2002 and is still in operation today, and the older Wide Field and Planetary Camera 2, which was in use from 1993 to 2009. The data used here were taken more than 20 years apart for two different observing programmes — a real testament to Hubble’s long scientific lifetime!

Both programmes aimed to understand the demise of massive stars. In one, researchers studied the sites of past supernovae, aiming to estimate the masses of the stars that exploded and investigate how supernovae interact with their surroundings. NGC 4900 was selected for study because it hosted a supernova named SN 1999br.

In the other programme, researchers laid the groundwork for studying future supernovae by collecting images of more than 150 nearby galaxies. After a supernova is detected in one of these galaxies, researchers can examine these images, searching for a star at the location of the supernova. Identifying a supernova progenitor star in pre-explosion images gives valuable information about how, when and why supernovae occur.

[Image Description: A spiral galaxy seen face-on. Broken spiral arms made of blue patches of stars and thin strands of dark dust swirl around the galaxy’s centre, forming a broad, circular disc. An extended circular halo surrounds the disc. The centre is a brightly-glowing, stubby bar-shaped area in a pale yellow colour. A bright star in our own galaxy, with long cross-shaped diffraction spikes, is visible atop the distant galaxy.]

Credit:  ESA/Hubble & NASA, S. J. Smartt, C. Kilpatrick

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From NASA's James Webb Space Telescope, March 10, 2025: The Flame Nebula lies in the Orion Molecular Cloud Complex and is home to cosmic objects that are not quite planets, but are also so small their cores can’t sustain fusing hydrogen like full-fledged stars do - brown dwarfs.

Decades of Hubble data was crucial in identifying candidates for further study, essentially handing the baton to Webb to take an in-depth look at this region using its infrared sensitivity.

Webb took a look at the Orion Molecular Cloud Complex, looking for the faintest and the smallest of brown dwarfs.

Brown dwarfs are very dim and much cooler than stars, making them hard to detect. When they are young, they are a bit warmer and brighter and easier to observe, making the Flame Nebula star-forming region (within this molecular cloud complex) a good place to look for them.

Webb’s ability to see warm objects through dense dust is allowing Webb not only to find brown dwarf candidates, but also to explore their lowest mass limits. Though Webb has the infrared sensitivity to potentially see brown dwarfs as low-mass as half that of Jupiter, the lowest-mass objects scientists found are about 2-3 times the mass of Jupiter. The current hypothesis that this might be at or near the lower limit for the mass of brown dwarfs. This also takes into account the dynamics at play within the molecular clouds where these objects are born.

Credit: NASA, ESA, CSA, STScI, Michael Meyer (University of Michigan), Matthew De Furio (UT Austin), Massimo Robberto (STScI), Alyssa Pagan (STScI)

Image description: There is an orange and yellow fang-like cloud of matter that cuts the image in two. The left side of the fang shows more clouds of a dark brown shade, while the right shows filaments of light brown. There are a number of bright blue and red points of light spread throughout.