Andromeda Shadow Plug In Hanging
Welcome back to Messier Monday! In our ongoing tribute to the great Tammy Plotner, we take a look at the Andromeda Galaxy, also known as Messier 31. Enjoy!During the 18th century, famed French astronomer noted the presence of several “nebulous objects” in the night sky. Having originally mistaken them for comets, he began compiling a list of them so that others would not make the same mistake he did. In time, this list (known as the ) would come to include 100 of the most fabulous objects in the night sky.One of these objects is the famed Andromeda Galaxy, the closest spiral galaxy to the Milky Way which is named for the area of the sky it appears in (in the vicinity of the ). It is the largest galaxy in the Local Group, and has the distinction of being one of the few objects that is actually getting closer to the Milky Way (and is expected to merge with us in a few billion years!). Description:Approaching us at roughly 300 kilometers per second, our massive galactic neighbor has been the object of studies of spiral structure, globular and open clusters, interstellar matter, planetary nebulae, supernova remnants, galactic nucleus, companion galaxies, and more for as long as we’ve been peering its way with a telescope.
It’s part of our Local Group of galaxies and its two easily visible companions are only part of the eleven others that swarm around it.One day, this galaxy will collide with our own, much as it is now consuming its neighbor – M32. However, this won’t come to pass for several billions years, so don’t go worrying about the immense gravitational disturbances just yet!
And not surprisingly, a giant galaxy like Andromeda doesn’t get to be so big by keeping to itself. How many times now has the Great Andromeda Galaxy consumed another? More than once!In 1993, the Hubble Space Telescope revealed that M31 has a double nucleus – a ‘leftover’ from another meal! As NASA and the ESA at the time. “Each of the two light-peaks contains a few million densely packed stars.
The brighter object is the “classic” nucleus as studied from the ground. However, HST reveals that the true center of the galaxy is really the dimmer component. One possible explanation is that the brighter cluster is the leftover remnant of a galaxy cannibalized by M31. Another idea is that the true center of the galaxy has been divided in two by deep dust absorption across the middle, creating the illusion of two peaks. This green-light image was taken with HST’s Wide Field and Planetary Camera (WF/PC), in high resolution mode, on July 6, 1991. The two peaks are separated by 5 light-years. The Hubble image is 40 light-years across.”Perhaps one of the most fascinating discovery recent years in Messier 31 was made by the orbiting Chandra X-Ray Observatory.
The X-ray image below, made with the Chandra X-Ray Astronomy Center’s Advanced CCD Imaging Spectrometer (ACIS), shows the central portion of the Andromeda Galaxy. The Chandra X-ray Observatory is part of NASA’s fleet of “Great Observatories” along with the Hubble Space Telescope. The Andromeda galaxy as seen in optical light, and Chandra’s X-ray vision of the changing supermassive black hole in Andromeda’s heart. Credit: X-Ray NASA/CXC/SAO/Li et al.), Optical (DSS)The blue dot in the center of the image is a “cool” million degree X-ray source where Andromeda’s massive central object, with the mass of 30 million suns, is located, which many astronomers consider to be a supermassive black hole. Most of these are probably due to X-ray binary systems, in which a neutron star (or perhaps a stellar black hole) is in a close orbit around a normal star.”Over the years our studies have advanced even more with the discovery of an eclipsing binary star in Messier 31. As Ignasi Ribas (et al) put it.
“We present the first detailed spectroscopic and photometric analysis of an eclipsing binary in the Andromeda Galaxy (M31). This is a 19.3 mag semidetached system with late O and early B spectral type components. From the light and radial velocity curves we have carried out an accurate determination of the masses and radii of the components.
Their effective temperatures have been estimated by modeling the absorption-line spectra. The analysis yields an essentially complete picture of the properties of the system, and hence an accurate distance determination to M31.”In 2005, we discovered more.
At that time, Scott Chapman of Caltech, Rodrigo Ibata of the Observatoire de Strasbourg, and their colleagues conducted detailed studies on the motions and metals of nearly 10,000 stars in Andromeda, which that the galaxy’s stellar halo is “metal-poor.” Essentially, this indicated that the stars lying in the outer bounds of the galaxy are lacking in elements heavier than hydrogen. Image of the Andromeda Galaxy, showing Messier 32 to the lower left, which is currently merging with Andromeda. Credit: Wikipedia Commons/Torben HansenAccording to Chapman, this was surprising since one of the key differences thought to exist between Andromeda and the Milky Way was that the former’s stellar halo was metal-rich and the latter’s was metal-poor. If both galaxies are metal-poor, then they must have had very similar evolutions.
As Chapman:“Probably, both galaxies got started within a half billion years of the Big Bang, and over the next three to four billion years, both were building up in the same way by protogalactic fragments containing smaller groups of stars falling into the two dark-matter haloes.”While no one yet knows what dark matter is made of, its existence is well established because of the mass that must exist in galaxies for their stars to orbit the galactic centers. In fact, current theories of galactic evolution assume that dark-matter wells acted as a sort of “seed” for today’s galaxies, with the dark matter pulling in smaller groups of stars as they passed nearby. What’s more, galaxies like Andromeda and the Milky Way have each probably gobbled up about 200 smaller galaxies and protogalactic fragments over the last 12 billion years. Chapman and his colleagues arrived at the conclusion about the metal-poor Andromeda halo by obtaining careful measurements of the speed at which individual stars are coming directly toward or moving directly away from Earth. The Andromeda Galaxy, viewed using conventional optics and IR. Credit: Kitt Peak National ObservatoryThis measure is called the radial velocity, and can be determined very accurately with the spectrographs of major instruments such as the 10-meter Keck-II telescope, which was used in the study.
Of the approximately 10,000 Andromeda stars for which the researchers have obtained radial velocities, about 1,000 turned out to be stars in the giant stellar halo that extends outward by more than 500,000 light-years.These stars, because of their lack of metals, are thought to have formed quite early, at a time when the massive dark-matter halo had captured its first protogalactic fragments. The stars that dominate closer to the center of the galaxy, by contrast, are those that formed and merged later, and contain heavier elements due to stellar evolution processes.In addition to being metal-poor, the stars of the halo follow random orbits and are not in rotation. By contrast, the stars of Andromeda’s visible disk are rotating at speeds upwards of 200 kilometers per second.According to Ibata, the study could lead to new insights on the nature of dark matter. “This is the first time we’ve been able to obtain a panoramic view of the motions of stars in the halo of a galaxy,” says Ibata.
“These stars allow us to weigh the dark matter, and determine how it decreases with distance.” History of Observation:Andromeda was known as the “Little Cloud” to Persian astronomer Abd-al-Rahman Al-Sufi, who described and depicted it in 964 AD in his. This wonderful galaxy was also cataloged by Giovanni Batista Hodierna in 1654, Edmund Halley in 1716, by Bullialdus 1664, and again by Charles Messier in 1764. The Andromeda Galaxy is a spiral galaxy approximately 2.5 million light-years away in the constellation Andromeda. Credit: Wikipedia Commons/Adam EvansLike most of the objects he added to the Messier Catalog, he mistook the galaxy initially for a nebulous object. As he wrote of the object in his notes. “The sky has been very good in the night of August 3 to 4, 1764; and the constellation Andromeda was near the Meridian, I have examined with attention the beautiful nebula in the girdle of Andromeda, which was discovered in 1612 by Simon Marius, and which has been observed since with great care by different astronomers, and at last by M. Le Gentil who has given a very ample and detailed description in the volume of the Memoirs of the Academy for 1759, page 453, with a drawing of its appearance.
Shadowify
Simply identify the large diamond-shaped pattern of stars that is the Great Square of Pegasus. The northernmost star is Alpha, and it is here we will begin our hop. Stay with the northern chain of stars and look four finger widths away from Alpha for an easily seen star. The next along the chain is about three more finger widths away.
Andromeda Shadow Plug In Hanging System
Two more finger widths to the north and you will see a dimmer star that looks like it has something smudgy nearby. The location of Messier 31, in the Andromeda constellation (from which it takes its name). Credit: IAU/Sky & Telescope magazine (Roger Sinnott & Rick Fienberg)Point your binoculars there, because that’s no cloud – it’s the Andromeda Galaxy! Now aim your binoculars or small telescope its way Perhaps one of the most outstanding of all galaxies to the novice observer, M31 spans so much sky that it takes up several fields of view in a larger telescope, and even contains its own clusters and nebulae with New General Catalog designations.If you have a slightly larger telescope, you may also be able to pick up M31’s two companions – M32 and M110. Even with no scope or binoculars, it’s pretty amazing that we can see something – anything! – that is over two million light-years away!
In 2006, astronomers spotted the telltale sign of a supernova detonating in the galaxy NGC 1260, located about 240 million light-years away in the constellation of Perseus. As telescopes around the world turned their collective light-gathering power on the expanding explosion designated as SN 2006gy, they realized they were seeing something very unusual.This clearly wasn’t a regular supernova. It grew to be 100 times brighter than the typical stellar explosion and lasted much much longer.More than a decade after that cosmic explosion, astronomers finally think they know what series of events led to the release of this much energy, now called a superluminous supernova.
A red giant ate a white dwarf. An event so rare it probably accounts for only 1 in 1000 supernovae.Our Book is out!Podcast version:ITunes: email newsletter:Space Hangout:Cast:us at stories at @universetodayFacebook: - Fraser Cain - @fcain /Karla Thompson - @karlaii / Weber -References:Universe Today podcasts with Fraser Cain.