Credit: NASA/CXC/INAF/Argiroffi, C. et al.
Illustration: NASA/GSFC/S. Wiessinger
This artist's illustration depicts a coronal mass ejection, or CME,
from a star. These events involve a large-scale expulsion of material,
and have frequently been observed on the Sun. A new study using NASA's Chandra X-ray Observatory has detected a CME from a different star, as reported in a new press release,
providing a novel insight into these powerful phenomena. As the name
implies these events occur in the corona, which is the outer atmosphere
of a star.
This "extrasolar" CME was seen from a star called HR 9024, which is located about 450 light years
from Earth. This represents the first time that researchers have
thoroughly identified and characterized a CME from a star other than the
Sun. This event was marked by an intense flash of X-rays followed by the emission of a giant bubble of plasma, i.e., hot gas containing charged particles.
The results confirm that CMEs are produced in magnetically active
stars, and they also open the opportunity to systematically study such
dramatic events in stars other than the Sun.
The High-Energy Transmission Grating Spectrometer,
or HETGS, aboard Chandra is the only instrument that allows
measurements of the motions of coronal plasmas with speeds of just a few
tens of thousands of miles per hour, like those observed in HR 9024.
During the flare, the Chandra observations clearly detected very hot
material (between 18 to 45 million degrees Fahrenheit) that first rises
and then drops with speeds between 225,000 to 900,000 miles per hour.
This is in excellent agreement with the expected behavior for material
linked to the stellar flare.
A coronal mass ejection (CME) of our Sun as observed by
NASA's Solar Dynamics Observatory on August 31, 2012.
A paper describing this study appeared in the May 27, 2019 issue of Nature Astronomy and a preprint is available here.
The lead author is Costanza Argiroffi of University of Palermo in Italy
and the National Institute for Astrophysics (INAF) in Italy. NASA's
Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra
program for NASA's Science Mission Directorate in Washington. The
Smithsonian Astrophysical Observatory in Cambridge, Massachusetts,
controls Chandra's science and flight operations.
Fast Facts for HR 9024:
Category: Normal Stars & Star Clusters
Coordinates (J2000): RA 23h 49m 40.80s | Dec 36° 25´ 31.00"
Constellation: Andromeda
Observation Date: August 2001
Observation Time: 27 hours 13 minutes
Obs. ID: 1892
Instrument: HETG
References: Argiroffi, C. et al, 2019, Nature Astronomy, arXiv:1905.11325
Distance Estimate: About 450 light years
Source: NASA’s Chandra X-ray Observatory
