Atlas Image mosaic, covering 15.0´ × 15.0´ on the sky, showing
the infrared sources RAFGL 5180 and 5182 (IRAS 06058+2138 and 06061+2151,
respectively). These are both embedded dense clusters of massive young stars
in the Gemini OB1 molecular cloud complex (Carpenter, Snell, & Schloerb 1995,
ApJ, 450, 201), near the HII region Sharpless 247. These data are part of the
Spring 1999 data release. Image mosaic by S. Van Dyk (IPAC).
Atlas Image, covering 5.4´ × 5.4´ on the sky, showing the
Eskimo Nebula (NGC 2392). This is a planetary nebula, showing a double
ring structure. Planetary nebulae are formed as low-mass stars, like the Sun,
reach the end of their lives and lose their outer envelopes to the interstellar
medium. From an analysis of the nebula's kinematics, O'Dell, Weiner, &
Chu (1990, ApJ, 362, 226) proposed a model where the observer is looking
into a bipolar stellar wind flow from the hot central star (seen in the image
brightly at the nebula's center). The star first lost mass during the extended
red giant envelope stage from the equator of the precursor star, forming the
outer disk, or ring, ~5300 yr ago;
the inner disk, or ring, with an age of ~1000 yr, represents a more recent,
strong, ongoing wind. The central star will eventually evolve to a
white dwarf, as the nebular gas dissipates. Latter et al. (1995, ApJS, 100,
159) previously imaged the Eskimo in the near-infrared; in the case of this
nebula, the near-IR emission is dominated by reradiated light from the central
star by nebular dust
likely formed during the precursor star's asymptotic giant branch phase.
These data are part of the Spring 1999 data release.
Atlas Image, covering
4.4´ × 6.2´ on the sky, showing the Solar System asteroid
2 Pallas, one of the most studied and the second brightest of these
minor planets. These data are part of the Spring 1999
data release, which will contain a number of other detections of known
asteroids. Identification of the objects takes place as part of the 2MASS
pipeline processing. This image appears in the
2MASS Image Gallery of Solar System objects.
Near-infrared photometry of asteroids can tell much
about the Sun-reflecting surface composition, for example, the amount and
nature of any organic solids or ices coating the asteroid's rocky interior.
The properties of this regolith affect the albedo, or reflectivity, of the
asteroid. Using thermal emission models for asteroids, for instance, a number
of parameters, including diameter and thermal history, can be derived. The
observed colors and inferred compositions of asteroids can place constraints
on the thermal environment in the early Solar System, providing clues to the
formation of the major planets, including the Earth.
An image mosaic, covering
14.2´ × 14.2´ on the sky, of the star formation complex and
young stellar outflow Cepheus A, at 725 pc (2400 light years) distant.
The infrared bright core of the radio source Cepheus A, to the northwest in the
mosaic, contains a number of highly obscured young, massive stars and
molecular gas. A complex molecular outflow extends from the core. The core
itself is obscured by more than 100 magnitudes of optical extinction!
Reflection nebulae, bright Herbig-Haro objects, bow shocks, and jets are also
seen in the complex (Hartigan et al. 1996, AJ, 111, 1278). The bright nebula
to the southeast in the mosaic is IRAS 22551+6139, also a probable young
stellar object. These data are part of the Spring 1999 data release.
Image mosaic by R. Cutri (IPAC).
This image of the nearby barred spiral galaxy Maffei 2, covering
12.0´ × 14.4´ on the sky, appears in the
2MASS Image Gallery of extragalactic objects. Maffei 2 is located
near the Galactic Plane, at galactic longitude l=136.50 and
latitude b=-0.33, and suffers from ~5 magnitudes of visual
extinction. As such, it wasn't recognized as a galaxy until it was initially
detected in the near-infrared as an anomalous source by Maffei (1968. PASP, 80,
618) and its morphological type was identified by Spinrad et al. (1971, ApJ,
163, L25). Maffei 2, at a distance of about 5 Mpc (16.3 million light years),
and its nearby elliptical companion, Maffei 1 (see the
Image Gallery), highlight the importance of the near infrared, and,
specifically, 2MASS, as a window
on galaxies behind the Milky Way disk in the so-called "Zone of Avoidance",
where they are hidden due to Galactic dust. Although its gas
kinematics are consistent with those of other barred galaxies, Maffei 2 in
the infrared, radio continuum and H I emission appears markedly disturbed.
The structural asymmetries, as well as the nuclear starburst, are possibly
driven by an ongoing merger with a small satellite companion galaxy (Hurt,
Turner, & Ho 1996, ApJ, 466, 135).
These data are part of the Spring 1999 data release.
Image mosaic by R. Cutri (IPAC).
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