The Pleiades in IR


Pleiades_WISEOne of my favorite objects in the autumn sky is the Pleiades. This false-color image shows the star cluster as seen through the eyes of WISE, the Wide-field Infrared Survey Explorer. It’s a mosaic of several hundred images from the more than one million WISE captured in its first survey of the entire sky in infrared light.

All four infrared detectors aboard WISE were used to make this mosaic. Blue and cyan represent infrared light at wavelengths of 3.4 and 4.6 µm, which is dominated by light from stars. Green and red represent light at 12 and 22 µm, which is mostly light from warm dust.

Image Credit: NASA

Brown Dwarf


BrownDwarfThis animation shows the coldest brown dwarf found to date. It also the fourth closest system to our Sun. WISE J085510.83-071442.5 is a very dim object that was noticed because of its rapid motion across the sky. It first showed up in two infrared images taken six months apart in 2010 by the Wide-field Infrared Survey Explorer, or WISE (the orange triangles). Two more images of the object were taken with the Spitzer Space Telescope in 2013 and 2014 (green triangles). Because the two satellites are in different orbits, their data could be used to calculate the distance to the brown dwarf: 7.2 light-years. The Spitzer data were used to show that the body appears to be roughly the same temperature as the Earth’s North Pole (-48 to -13 °C).

Image Credit: NASA

A Near Earth Asteroid


NearEarthAsteroidThe greenish-yellow dot in the upper left is the potentially hazardous near-Earth object 1998 KN3 moving past a cloud of dense gas and dust near the Orion nebula in the far, far background. NEOWISE, the asteroid-hunting portion of the Wide-field Infrared Survey Explorer, or WISE, mission, took this infrared picture. Because near-Earth asteroids are warmed by the Sun to roughly room temperature, they glow brightly at the infrared.

Infrared light from asteroids is used to measure their sizes. Combined with visible-light observations, that data can also measure the reflectivity of their surfaces. The WISE data reveal that this asteroid is about 1.1 km in diameter and reflects only about 7 percent of the visible light that falls on its surface. It is relatively dark.

In this image blue denotes shorter infrared wavelengths and red, longer. Hotter objects emit shorter-wavelength light; they appear blue. Stars with temperatures of thousands of degrees are blue. The coldest gas and dust are red. The asteroid appears greenish-yellow in the image because it is about room temperature—cooler than the stars, but warmer than the dust.

Image Credit: NASA

The Pleiades: Round 5


Pleiades_WISEThis false-color image shows the  Pleiades cluster of stars as seen through the eyes of WISE, the Wide-field Infrared Survey Explorer. It’s a mosaic of several hundred images from the more than one million WISE captured in its first survey of the entire sky in infrared light.

All four infrared detectors aboard WISE were used to make this mosaic. Blue and cyan represent infrared light at wavelengths of 3.4 and 4.6 µm, which is dominated by light from stars. Green and red represent light at 12 and 22 µm, which is mostly light from warm dust.

Image Credit: NASA

A Rare Luminous Blue Variable Star


The bright star to the right and above the center of the picture is cataloged as G79.29+0.46. It’s a massive luminous blue variable (LBV) star, one of only about 100 such stars in our galaxy. It’s very bright, but it can’t be seen from Earth in visible light because it’s extremely volatile and surrounded by a thick cloud of dust. The picture above is an infrared image put together by combining data from the Wide-Field Infrared Survey Explorer and the Spitzer Space Telescope. In this false color image the blue star appears green and the surrounding dust shell appears red.

Image Credit: NASA / Judy Schmidt (CC BY 2.0)

The Pleiades in IR


Pleiades_WISEThis false-color image shows the  Pleiades cluster of stars as seen through the eyes of WISE, the Wide-field Infrared Survey Explorer. It’s a mosaic of several hundred images from the more than one million WISE captured in its first survey of the entire sky in infrared light.

All four infrared detectors aboard WISE were used to make this mosaic. Blue and cyan represent infrared light at wavelengths of 3.4 and 4.6 µm, which is dominated by light from stars. Green and red represent light at 12 and 22 µm, which is mostly light from warm dust.

Image Credit: NASA

Brown Dwarfs


This is the first ultra-cool brown dwarf discovered by NASA's Wide-field Infrared Survey Explorer.A brown dwarf is an object that didn’t quite make it to stardom. It’s sub-stellar without enough mass to sustain hydrogen-1 fusion like a main sequence star. Brown dwarfs fill a niche between large planets and lightweight stars, ranging unto about 75X the mass of Jupiter. Brown dwarfs with mass greater 13X MJ may be able to fuse deuterium, and dwarf’s with mass above 75X MJ may be able to fuse lithium.

WISE 0458+6434 was the first ultra-cool brown dwarf discovered by the Wide-field Infrared Survey Explorer. It’s the green dot in the picture above which is from infrared data coded as green and blue depending on wavelength. WISE 0458+6434 is a binary system of two (A and B) ultracool brown dwarfs. The primary (A) has a mass about 15X Jupiter’s and a surface temperature of around 600 K or about 330 C. That’s roughly a tenth of the surface temperature of the Sun. Brown dwarfs have found with surface temperatures as low as -150 C.

Image Credit: NASA

Brown Dwarf


BrownDwarfThis animation shows the coldest brown dwarf found to date. It also the fourth closest system to our Sun. WISE J085510.83-071442.5 is a very dim object that was noticed because of its rapid motion across the sky. It first showed up in two infrared images taken six months apart in 2010 by the Wide-field Infrared Survey Explorer, or WISE (the orange triangles). Two more images of the object were taken with the Spitzer Space Telescope in 2013 and 2014 (green triangles). Because the two satellites are in different orbits, their data could be used to calculate the distance to the brown dwarf: 7.2 light-years. The Spitzer data were used to show that the body appears to be roughly the same temperature as the Earth’s North Pole (-48 to -13 °C).

Image Credit: NASA

IR Trifid


Trifid in IRRadiation and winds from massive stars have blown a cavity into the surrounding dust and gas, creating the Trifid nebula, as seen here in infrared light. The false color image was assembled from data collected by the Wide-field Infrared Survey Explorer.

Image Credit: NASA

A Near Earth Asteroid


NearEarthAsteroidThe greenish-yellow dot in the upper left is the potentially hazardous near-Earth object 1998 KN3 moving past a cloud of dense gas and dust near the Orion nebula in the far, far background. NEOWISE, the asteroid-hunting portion of the Wide-field Infrared Survey Explorer, or WISE, mission, took this infrared picture. Because near-Earth asteroids are warmed by the Sun to roughly room temperature, they glow brightly at the infrared.

Infrared light from asteroids is used to measure their sizes. Combined with visible-light observations, that data can also measure the reflectivity of their surfaces. The WISE data reveal that this asteroid is about 1.1 km in diameter and reflects only about 7 percent of the visible light that falls on its surface. It is relatively dark.

In this image blue denotes shorter infrared wavelengths and red, longer. Hotter objects emit shorter-wavelength light; they appear blue. Stars with temperatures of thousands of degrees are blue. The coldest gas and dust are red. The asteroid appears greenish-yellow in the image because it is about room temperature—cooler than the stars, but warmer than the dust.

Image Credit: NASA

Meet the New Neighbors


brown_dwarfsWISE J104915.57-531906 is at the center of the main image, which was taken by the  Wide-field Infrared Survey Explorer (WISE). This is the closest star system discovered since 1916, and the third closest to our sun. It is 6.5 light-years away. At first, the light appeared to be from a single object, but a sharper image from Gemini Observatory in Chile revealed that it was from a pair of cool star-like bodies called brown dwarfs.

The pair is only slightly farther away than the second-closest star, Barnard’s star, which was found 6 light-years away in 1916. The closest star system consists of: Alpha Centauri, found in 1839 at 4.4 light-years away, and the fainter Proxima Centauri, discovered in 1917 at 4.2 light-years.

Since WISE J104915.57-531906 is only 6.5 light-years away Earth’s television transmissions from 2006 are now arriving there, and viewers there are still watching the first season of the Tenth Doctor with David Tennant.

Image Credit: NASA

There’s a Comet Coming


Beginning on 12 March, a comet will be visible in the early evening sky. There’s information on where in the sky to look here.comet

Meanwhile, here’s a view of a comet taken by Wide-field Infrared Survey Explorer or WISE. This comet, known as C/2007 Q3, was discovered in 2007 by Australian observers. The snowball-like mass of ice and dust spent billions of years orbiting out in the deep freeze of the Oort Cloud, the cloud of comets surrounding the Solar System. Eventually, it got diverted from of this original orbit and onto a course bringing it closer to the Sun. Sunlight warmed the comet, causing it to shed ices and dust in a long tail that trails behind it.

In October, 2009, it passed as close as 1.2 astronomical units from Earth and 2.25 astronomical units from the sun (an astronomical unit is the average distance between the Sun and Earth). In this infrared image, longer wavelengths are shown in red and shorter wavelengths are blue. The comet appears red because it is much colder than the background stars. Colder objects give off more of their light at longer wavelengths. An ice cube, for example, pours out a larger fraction of its light at longer infrared wavelengths than does a cup of hot coffee.

Image Credit: NASA

The Orion Nebula in Infrared


Orion nebula 800-600The Orion nebula is featured in this image from the Wide-field Infrared Survey Explorer, or WISE. The constellation Orion is prominent in the night sky from December through April. The nebula (aka Messier 42 or M42) is in Orion’s sword which hangs from his famous belt of three stars. The star cluster embedded in the nebula appears to be a single fuzzy star to the naked eye.

The Maya of Mesoamerica envisioned the lower portion of Orion, what we call his belt and feet, as being the hearthstones of creation, similar to the triangular three-stone hearth at the center of traditional Maya homes. The Orion nebula, lying at the center of the triangle, was seen by the Maya as the cosmic fire of creation surrounded by smoke. That turns out to be an apt metaphor. The nebula is an enormous cloud of dust and gas where new stars are being born. It is one of the closest nurseries of star formation to the Earth and, therefore, provides astronomers with their best view of stellar formation.

This picture spans more than six times the width of the full moon, covering a region nearly 100 light-years across. The green stuff surrounding the nebula is interstellar dust. Color in this image represents specific infrared wavelengths. Blue represents light emitted at around 3.4 µm wavelength, and cyan represents 4.6 µm, both of which are generated mostly by hot stars. Relatively cooler objects, such as the dust of the nebulae, appear green and red. Green represents 12 µm light, and red represents 22 µm light.

Image Credit: NASA