Baby Star’s Hot Birthmarks

Astronomers have pinpointed the origin of high-energy X-rays coming from a baby star.

In January 2004, amateur astronomer Jay McNeil spotted a nebula no one had ever catalogued. This nebula, now called McNeil’s Nebula, is a fan-shaped feature just southwest of M78 near Orion’s belt. The nebula is made of dusty gas clouds that reflect light from a baby star called V1647 Ori.

McNeil's Nebula
McNeil's Nebula is seen here imaged with a 20-inch telescope and CCD camera using Red, Green, Blue filters, and unfiltered light.
Astronomers soon discovered that McNeil’s Nebula isn’t actually new: it’s been flaring in and out of view whenever V1647 Ori swallows too much gas too fast from its surrounding disk of infalling material. When it does, the forming star burps in an outburst that makes the nearby gas visible. The nebula shows up in an image taken in 1966, but not in shots of the same region from 1951 and 1988. The outburst that allowed McNeil to spot the object lasted until 2006; another one began in 2008 and looks to be ongoing.

When these protostars belch, their brightness in X-rays can surge by a factor of 100. Astronomers suspected that the X-rays come from the accreting material, but it hasn’t been clear exactly where in the star-disk system that origin lies.

So a French and American team looked through observations taken by the X-ray orbiting telescopes Chandra, XMM-Newton, and Suzaku of V1647 Ori during its two recent outbursts to figure out what’s afoot. As they report in the July 20th issue of The Astrophysical Journal, the star appears to have two hotspots on its surface — the team calls them “pancake-shaped magnetic footprints” — where the infalling gas stream feeds the newborn star. These hotspots emit the X-rays. NASA has put out a pretty cool video that shows what’s going on, which you can watch below or on YouTube. You can also read more about the results in the press release from the Rochester Institute of Technology, and the full story behind McNeil’s discovery appeared in our June 2004 issue.

One thought on “Baby Star’s Hot Birthmarks

  1. Peter WilsonPeter

    The infalling gas stream that feeds newborn stars has to lose energy somehow. Might as well be x-rays. BTW, the video says astronomers discovered McNeil’s Nebula in 2003. Can’t help but wonder if astronomers discovered sometime after McNeil’s discovery that they had discovered it before him.

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