Credit: X-ray: NASA/CXC/INAF/M.Guarcello et al.; Optical: NASA/STScI
Credit: X-ray: NASA/CXC/INAF/M.Guarcello et al.; Optical: NASA/STScI
Optical and infrared identifications with stars were used to sort out
chance interlopers in the foreground or background, and to determine
that more than two-thirds of the sources are likely young stars that are
members of the NGC 6611 cluster.
Chandra's unique ability to resolve and locate X-ray sources made it
possible to identify hundreds of very young stars, and those still in
the process of forming (known as "protostars"). Infrared observations
from NASA's Spitzer Space Telescope and the European Southern
Observatory indicate that 219 of the X-ray sources in the Eagle Nebula
are young stars surrounded by disks of dust and gas and 964 are young
stars without these disks.
Combined with the Chandra
observations, the data show that X-ray activity in young stars with
disks is, on average, a few times less intense that in young stars
without disks. This behavior is likely due to the interaction of the
disk with the magnetic field of the host star. Much of the matter in the
disks around these protostars will eventually be blown away by
radiation from their host stars, but, in certain cases, some of it may
form into planets.
This new composite image shows the region around the Pillars, which are about 5,700 light years
from Earth. The image combines X-ray data from NASA's Chandra X-ray
Observatory and Hubble Space Telescope optical data. The optical image,
taken with filters to emphasize the interstellar gas and dust, shows
dusty brown nebula immersed in a blue-green haze, and a few stars that
appear as pink dots in the image. The Chandra data reveal X-rays from
hot outer atmospheres from stars. In this image, low, medium, and
high-energy X-rays detected by Chandra have been colored red, green, and
blue.
In the image, some of the X-ray sources appear to be located in the
Pillars. However, an analysis of the absorption of X-rays from these
sources indicates that almost all of these sources belong to the larger
Eagle Nebula rather than being immersed in the Pillars.
Three X-ray sources appear to lie near the tip of the largest Pillar.
Infrared observations show a protostar containing four or five times
the mass of the Sun is located near one of these sources — the blue one
near the tip of the Pillar. This source exhibits strong absorption of
low-energy X-rays, consistent with a location inside the Pillar. Similar
arguments show that one of these sources is associated with a disk-less
star outside the Pillar, and one is a foreground object.
A paper by Mario Guarcello, currently at the National Institute for Astronomy in Italy, and colleagues describing these results appeared in The Astrophysical Journal.
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 The Eagle Nebula (M16):
Scale: Image is about 2.5 arcmin (5.13 light years across) across
Category: Normal Stars & Star Clusters
Coordinates (J2000): RA 18h 18m 51.79s | Dec -13º 49' 54.93"
Constellation: Serpens
Observation Date: 07/30/2001
Observation Time: 22 hours
Obs. ID: 978
Instrument: ACIS
References: M. Guarcello et al. 2012, ApJ, 753, 117; arXiv:1205.2111
Color Code: X-ray (larger point sources): Red (0.5-1.5 keV); Green (1.5-2.5 keV); Blue (2.5-7.0 keV); Optical (diffuse emission & smaller point sources): Red, Green and Blue
Distance Estimate: About 5,700 light years
Source: NASA’s Chandra X-ray Observatory
