Stellar evolution by joey


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Stellar evolution by joey

  1. 1. Stellar evolution Star Birth as a Protostar Stars are born within molecular clouds in the Galaxy. As the cloud collapses it fragments, and multiple stars are formed. We see an open (galactic) cluster as a result. As the star collapses, its overall density increases. As the density increases, the temperature and pressure at the center of star increases a well, quite dramatically. At this point in the star's life, its luminosity is provided by release of gravitational energy. Low-mass stars may take about a million years in this collapse until they finally arrive on the main sequence. Massive stars are born from huge molecular clouds. As protostars, they collapse much more rapidly than their low-mass counterparts, maybe going through the whole process in 10,000 years. The profuse amount of radiation produced by these O and B stars drive the dynamics and subsequent star formation of the whole cloud. Mass The mass of a protostar determines its place on the H-R diagram, its energy source, its ultimate fate. Low mass stars sit on the main sequence at low luminosities, low temperatures; high mass stars, at high luminosities and high temperatures. (Applying this to humans: it would be as if 6pound babies would always grow up to be lawyers; 8-pound babies, doctors; 10-pound babies, Paris models; etc.) For purposes of this discussion, we will call stars with less than 3 times the mass of the Sun "low-mass" stars. We will call stars with masses greater than 6 times the Sun's "high-mass stars." Those stars with masses in the range of 3 - 6 times the Sun don't get paid much attention here. Although they follow much of the story of a high-mass star, they do not get to have the catastrophic explosion at the end. As you will see, though, they do become somewhat rare objects A Brown Dwarf If the star does not have enough mass to create high enough temperatures and pressures in its core, then it can never commence hydrogen fusion. It may spend a brief time fusing deuterium (heavy hydrogen), but ultimately its only source of luminosity is the heat released during its gravitational collapse. It is doomed to cool for a very long time and eventually turn into a cold mass. If Jupiter had about 80 times its current mass, we would have a glowing, brown dwarf in the sky. (Image: NASA/STSCI/AURA) (Back) Low-Mass Stars: on the Main sequence As we learned when we studied the Sun, energy generation takes place in the core via the protonproton cycle: fusing 4 hydrogen nuclei (protons) into 1 helium nucleus (2 protons, 2 neutrons),
  2. 2. releasing energy in the process. The famous equation that explains where energy comes from, E = mc2, tells the whole story of how a little bit of mass can produce a whole lot of energy. Stars' lifetimes on the main sequence depend on their masses. Low mass stars spend 10 billions years or more, while high mass stars may stay for a mere 3-4 million years. The star's luminosity while on the main sequence is described by the mass luminosity relationship: L is proportional to M3.2. What this means is that even though high-mass stars have much more fuel than low-mass stars, they go through it at a much, much greater rate. (An analogy here on Earth: getting 70 mpg and having a 10-gallon tank versus getting 10 mpg and having a 20-gallon tank. The efficient car can go 700 miles on a tank of gas, while the lowmilage car barely covers 200 miles.) While on the main sequence, the star is in hydrostatic equilibrium: the outward pressure exerted by hot plasma--heated by the energetic photons produced in the core--balances the inward pressure due to the force of gravity. For stars roughly the mass of our star, outside the core lies the radiative envelope where the photons partake in a "random walk". It takes roughly a million years for a photon to get from the core (as a gamma ray) to the surface (as a visible light photon). The photon travels a mere 1 cm before being scattered by an electron or an ion. Outside the radiative envelope lies the convection zone (convective envelope). Heat is transferred here by the bulk movement of material. The top of the convection zone displays granulation at the base of the atmosphere. The atmosphere (if the star is similar to our Sun) has a photosphere, a chromosphere, and a corona. Many stars have huge starspots on their surface that can be detected by telescopes here on Earth. Red Giant Star This field of stars in the constellation of Sagittarius ( Courtesy Hubble Heritage Team and NASA) shows stars of many colors, including those that are orange and red. These stars are the "red giant stars." The cores of red giant stars are composed primarily of helium, ashes from the billions of years of fusion of hydrogen. The temperature in the core is not yet high enough to fuse elements heavier than helium. Without any support from energy generation, the helium core contracts. Here is where we can bring in our basic knowledge of physics: the material in the outer core has gravitational potential energy (GPE). When the core contracts, this GPE releases a profusion of energy--kinetic and thermal. The heat from this contraction causes the hydrogen in a shell surrounding core to ignite and we get "hydrogen-shell fusion.". The core will continue to contract and release energy until it cannot contract any further without squeezing the electrons together. The core is now supported by electron degeneracy--no two electrons can exist in the same state, and resist doing so with enough force to halt the collapse. The fusion of hydrogen to helium in the shell and the radiation pressure that results supports the rest of the star from gravitational collapse. The hydrogen shell produces a lot of energy. In a simplified interpretation of why stars turn into red giants (astronomers aren't really sure why this happens), we assume that because the hydrogen shell is closer to the surface of the star and the
  3. 3. luminosity of that shell is very high, the outer layers of the star expand. THE STAR BECOMES A RED GIANT. The star itself does not gain or lose mass (at least it has not lost much mass up to this stage) during its whole life, unless it is in a close-binary system where the stars are so close they are influencing each other dramatically. But, as the hydrogen-fusing shell works its way out through the interior of the star, it continuously "rains" helium ash onto the core of the star. The core is slowly gaining mass at the expense of the rest of the star. This extra mass is squeezing the core, raising the temperature there and steadily trying to raise the density. Helium Flash! and Horizontal Branch At left is a Hubble Space Telescope of the globular cluster 47 Tucanae. The large number of red giant stars in this cluster is noticeable by the distinctly yellowish-orange color of these stars. (Image courtesy W. Keel and NASA) Helium core fusion starts in the core of a red giant when the core temperature and density reaches 108 K and 108 kg/m3. As a red giant, the core was supported by electron degeneracy. Degeneracy is a strange state of matter indeed. Normal rules of physics do not apply here. A degenerate stellar core does not follow normal gas laws that dictate if something shrinks, the pressure and temperature rise, or if something expands, its pressure and temperature decreases. Once there is enough mass dumped on the core from the rest of the star, fusion starts in a runaway explosion of the entire core simultaneously. The red giant experiences a "helium flash." Unfortunately for us, we cannot see this flash; in fact, the rest of the star doesn't even know it happened until there appears to be a stable source of radiative support again. The degeneracy in the core disappears since fusion is now taking place. The star is supported by the energy produced via helium-to-carbon fusion in the core. The luminosity of the star decreases; the temperature increases. The star is in a second zone of stability, the horizontal branch, that will last a few billion years. Not all stars are totally stable in this region of the H-R Diagram. There are exceptions, stars that pulsate. These stars are called RR Lyrae Stars, and we will be getting better aquainted with these variable stars and what they have revealed about our galaxy in the lab: RR Lyrae Stars and the Distance to M4. Asymptotic Giant Branch (AGB) Eventually, over a time frame shorter than the hydrogen-fusion stage, the core of the horizontal-branch star will eventually run out of helium to fuse into carbon. Fusion shuts down, and the core starts to contract, having no means of supporting itself. This small, contracting core is made of carbon ash. The gravitational contraction releases the energy
  4. 4. that had been stored as potential energy, igniting a helium-fusing shell around it. Luminosity continues to be generated by the shrinking core until it again cannot contract anymore due to the onset of electron degeneracy. Meanwhile, back to the rest of the star: the rest of the star expands again and becomes an asymptotic giant branch star, almost retracing its path as a red giant star (see the link to the H-R diagram for the globular cluster 47 Tucanae shown to the right). The helium fusing shell surrounding the core rains down "carbon" ash. The luminosity produced by the helium-to-carbon fusion in this shell ignites a hydrogen-to-helium fusing shell on the outside of it. This is called a double-shell-burning star. The hydrogen shell is raining down helium ash to the helium-burning shell, while the helium shell is raining down carbon ash to the core. The two H and He fusing shells support the outer parts of the star. Outer atmosphere expands even more than before. Planetary Nebula Planetary Nebula Mz 3 (Courtesy Hubble Heritage Team NASA) and Energy production in the star will eventually stop as the Heand Hfusing shells work their way through the star. At this stage, the upper envelopes and the atmosphere are extremely unstable. Large pulsations in the star have driven almost half of the star's material into interstellar space, leaving behind only the once-active stellar core. This carbon core, supported now strictly by electron degeneracy, is extremely dense: 1010 kg/m3. The gaseous object surrounding the core is called a planetary nebula. It glows because of the energetic, ionizing photons produced by the now-exposed, extremely hot core. (Back) White Dwarf The star has finally reached the twilight of its years and has become a white dwarf: an immensely hot, Earth-sized object. What's left of a once magnificent star is doomed to a slow, slow death. What we see is the remnant of the core of the star. Its fate is to cool for billions and billions of years until it becomes a black, ultra-cold cinder. The carbon and other elements it contains will never be a part of the life of a star again. Massive white dwarfs are produced by stars whose mass lies between roughly 3 and 6 times the mass of the Sun. These white dwarfs contain mostly oxygen and neon, as well as some carbon, representing the fact that the star they came from was able to fuse elements slightly heavier than helium. These white dwarfs are rare as their mass lies right on the limit for electron degeneracy to be able to support the object from collapsing. If the white dwarf has a mass of slightly more than 1.4 times that of the Sun (the Chandrasekhar limit), it collapses into a neutron star. What this means for our star, Sol, and thus us
  5. 5. As you view the life track (evolutionary track) for the Sun, think about what this means for Earth and the life on it. Take it step by step (say, in 1-billion year steps!) and consider what will happen as the Sun's luminosity, and thus its brightness increases. On the zero-age-main-sequence, the luminosity of the Sun was roughly 70% of what it is today. The Sun has steadily been increasing in luminosity. There are fossil records that provide evidence that life in the form of very simple one-celled organisms got started approximately 3 billion years ago, almost immediately after conditions became favorable, after the Earth cooled down and the oceans were formed. Life has had to adjust to an increase in luminosity, can life continue to do so? What will we do when it is 90 degrees in Seattle in the middle of winter? As the oceans evaporate, the water vapor adds to the greenhouse effect of the atmosphere, causing an increase in the trapping of infrared radiation near the surface of the Earth. Solar radiation dissociates the water molecules, the hydrogen escapes, the oxygen reacts with other elements; the water is permanently lost. Will the human race be able to adapt on the short-term and be ready to pack bags and move out in the long-term? We could steadily move to the outer parts of the solar system as the Sun increases in luminosity, delaying the ultimate "move." There is plenty of water ice on the moons of the giant planets, perhaps we will be able to build shelters that can protect us from the Sun's harmful radiation. At the velocities possible with current propulsion systems, it would take 100,000 years or more to even reach the nearest star. We would need to populate interstellar space, with generations upon generations knowing only the mother ship and the cold, dark reaches in between the stars.
  6. 6. True-False Quiz (Back to top) Massive Protostars: NGC 7635, the Bubble Nebula, is 10 light-years across, more than twice the distance from the Earth to the nearest star. The nebula is made up of an expanding shell of glowing gas surrounding a hot, massive star in our Milky Way galaxy. This shell is being shaped by strong stellar winds of materials and radiation produced by the bright star at the left, which is 10 to 20 times more massive than our Sun. These fierce winds are sculpting the surrounding material, composed of gas and dust, into the curve-shaped bubble. (Hubble Heritage and NASA) High Mass Stars: On the Main Sequence Massive stars start their lives much like their solar counterparts, only they tend to over-do everything! They truly live fast and furious lives. In addition to the proton-proton cycle, massive stars can also produce energy by converting hydrogen to helium via the C-N-O cycle. Interior pressures and temperatures are so great that helium and carbon are often fused along with hydrogen, fusion isn't limited to just one process. (Image courtesy of J. Hester and NASA) One of the most massive stars ever observed, being about 150 times more massive than the Sun (or, theoretically, about as massive as any star can ever be), Eta Carinae is prone to massive outbursts. The most massive stars, like Eta Carinae, produce so much luminosity, that they literally blow much of their outer layers away early on in life. These stars have episodes where they brighten by many magnitudes and spew material into interstellar space. We expect this particular star, which may in fact be a binary system, to really "blow its top" some day. (Back) Evolution Away From the Main Sequence Massive stars spend very little time on the main sequence. For the most massive stars, this is only a few million years. These stars move to luminous red supergiant region as hydrogen is exhausted in core. The core contracts slightly, but since the star already has high enough temperatures to fuse helium to carbon via the triple-alpha process (review Section 13.4 of the text), it moves to this stage relatively smoothly. Along with a helium burning core, a hydrogento-helium fusing shell just outside of the core may also be present.
  7. 7. (Back) Helium Depletion in the Core The star has been primarily supported by helium-to-carbon fusion, but the helium has run out. The core again constracts. Some of the carbon and oxygen get fused into neon. As each new fusion process cycles to another, the star changes its temperature and moves from a red supergiant to a blue supergiant, and perhaps back to red again. At this stage in the star's life it is basically in hydrostatic equilibrium, although fusion in the core becomes dramatically dependent upon the temperature there. Any slight changes in the temperature results in extreme changes in the fusion rate. The carbon-to-oxygen-to-neon fusing core is surrounded by helium-to-carbon fusing shell which is surrounded by a hydrogento-helium fusing shell. As the fusion rates increase and decrease, the star's atmosphere responds. It is not unusual to find a red supergiant that changes its luminosity by 100 or more times (5 magnitudes) at this stage in its life. The image at the left is of the red supergiant, Betelgeuse, in Orion. (Image courtesy of A. Dupree and NASA) (Back) Middle- and Old-Age for High Mass Stars For these stars having masses originally greater than 6 times the Sun's, their outrageous "partying" isn't over yet. High-mass stars proceed to fuse oxygen to neon, neon to magnesium, magnesium to silicon, and finally silicon to iron (with intermediate steps along the way). Each stage leaves a "shell" of the previous stage fusing above it, raining ash onto the present core. Each stage happens progressively faster than the previous ones. The star is now caught in the cycle of depletion of one element to fuse in its core, contraction of the core, heating, fusion of the next heavier element, igniting of another fusing shell. Star "loops" across high-luminosity part of the HR Diagram as each stage progresses. When does fusion stop? The element iron has a particularly unique characteristic: its nucleus is the most tightly bound of any atom. Energy has been released as fusion as progressed from hydrogen to iron, but once an iron core is produced, fusion stops. No energy is forthcoming from fusing iron into a heavier element. Beyond iron, energy can be obtained only by fission. The star suddenly finds itself without any means of support against the force of gravity at all! (Back) The Mother of All Explosions: The Death of Massive Stars With no further support being provided for the star, gravity must win. The star starts to implode. The energy stored as gravitational potential energy is released suddenly. This energy results in the nuclei of the elements being split apart in a process called photodisintegration. All
  8. 8. the millions of years the star spent in fusing heavier and heavier elements was for naught. Even more energy disappears in this process--since energy was produced during the fusion, energy is needed for the splitting. The collapse accelerates as there is even less energy available for support. It gets worse! Protons and electrons are crushed together under extreme, unbelievable really, temperatures and pressures and form neutrons. Neutrinos are also formed in this merging, carrying away even more energy directly from the star. Electron degeneracy simply cannot act to support the core. The density of the core has now reached 1015 kg/m3. Just as a rubber ball will compress before it bounces back, the stellar core overshoots and rises to an astounding 1018 kg/m3. (There just are not enough superlatives in the English language to describe what is happening inside the dying star!) The core now rebounds with a vengeance, ricocheting shock waves and material back into interstellar space. This whole process takes place in less time than it took you to read this paragraph. Here is a simple animation (490 kb) depicting the aging of a massive star. Note that after each stage of fusion in the core, the core shrinks, generates enough heat and pressure to start the next stage of fusion to heavier elements and ignites another fusion shell. The gradual increase in the frame-rate is meant to depict the acceleration of each stage as heavier and heavier elements are fused. Then, the final stage when the core is fused to iron. The star implodes from all directions and then rebounds in a humongous explosion. Supernova 1987a (Image courtesy Hubble Heritage and NASA) provided observational support to the theory of these explosions. The Earth received a pounding of neutrinos first, although only a small fraction of the billions and billions passing through the Earth were detected. Since neutrinos do not interact with matter, they were able to escape the collapse first. The light from the explosion followed shortly afterward.
  9. 9. Neutron Stars The Crab Nebula is an example of what happens to the material from the supernova explosion. This supernova explosion happened in 1054 AD; the material is still speeding away from the neutron star left behind at 1000's of kilometers per second. Massive stars give almost all of their material back to interstellar space. Out of the 6-plus solar masses the star originally was born with, only between 1.4 and 3 solar masses remain in the neutron star (we deal with stellar black holes later). The neutron star is supported by "neutron degeneracy," a state similar to electron degeneracy, only much, much more dense. What remains of the star is essentially one huge atomic nucleus made of neutrons alone, an object about the size of the Earth but with an unbelievably high density. As the star explodes, there is also an abundance of neutrons spewing away from the neutron star. These neutrons run into nuclei of atoms and build up. When a neutron decays into a proton, a heavier element results. This process occurs very rapidly, with neutrons building up faster than they decay. In this way, the heaviest elements found on the periodic chart are formed--we can
  10. 10. think of no other way for them to be produced. (Think about the definition of alchemy--if humans could turn baser elements into gold, we would have done it by now.) In addition to this rapid neutron capture, the shock waves proceed through the expanding stellar material bringing densities, pressures, and temperatures high enough to fuse elements, and to force helium nuclei into other nuclei, building up the periodic chart even faster. Thus, the formation of the elements found in the Universe is completed. (Back) Pulsar or Neutron Star--What's the Difference? All pulsars are neutron stars, but not all neutron stars are pulsars. Observationally, a pulsar is an object that emits flashes of light several times per second or more, with near perfect regularity. Theoretically, pulsars are rapidly rotating neutron stars. What's the strongest evidence we have that pulsars are neutron stars? No massive object, other than a neutron star, could spin as fast as we observe pulsars spin. (Back) Back to the Interstellar Medium The gold you wear, the nickel in our coins, the uranium in the ground, silver, mercury, iron, copper, platinum--all were once atoms in a stupendous explosion. Carbon, nitrogen, oxygen, silicon, and the other essential chemicals for life were also produced in a supernova. Thus are we truly the children of the stars. An Interlude: The Periodic Chart and the Origin of the Elements (Back) Blackholes: The Ultimate Abyss Blackholes and their environment are so fascinating that they get a chapter all to themselves. You will have to wait until the next lesson to learn more about these intriguing and egnimatic objects. (Back) RR Lyrae and Cepheid Variable Stars RR Lyrae and Cepheid variable stars are one of the most important steps in the Distance Scale of the Universe. The stars lie in a region of the H-R diagram where stars are intrinsically variable. Variability is a normal part of their evolution. Variability is due to the ionization of helium and hydrogen.
  11. 11. RR Lyrae stars are old, low mass, stars occupying part of the horizontal branch. They are primarily found in the halo of galaxies, particularly the globular clusters. The average apparent magnitude of a star, say star #42 in the globular cluster M4, is 13.5. If we assume an absolute magnitude for all RR Lyrae stars is 0.75, what is the distance to Star #42 and thus M4? The distance to M4 is difficult to determine for the simple reason that it lies in a part of the Galaxy that is heavily obscured by dust. Click on the images to the left to see a larger view of each one. The globular cluster M4 is marked on the close-up image. Note that the close-up has been rotated clockwise by about 90 degrees. It is easy to see the long pillars of dust in the region. Astronomers estimate that the stars in M4 are dimmed by about 1 magnitude. The bright, yellowish star in these images is the red supergiant Antares. Here are two actual light curves of RR Lyrae stars. The one of the left is of the prototype star: RR Lyrae itself, with a period of 0.5668 days. The one shown on the right is a newly discovered one (2000), the discovery made by Dr. Scott Anderson and then graduate student Armin Rest using imaging data from the Sloan Digital Sky Survey. The plot was made from data taken by undergraduates in astronomy using the Monashtash Observatory in Ellensburg. The period for this star is 0.48588 days, an extremely precise determination. Note that the light curves measure the change in the apparent magnitude of the star and note also the similarity in the way the light curves look. (The data are not shown over time; rather, astronomers do a bit of an "accordion" calculation that essentially folds all of the data so that 1.5 periods are emphasized.) Cepheid stars are massive stars that are transversing the top of the H-R diagram as they evolve. They are usually found in the disks of galaxies, in regions of active star formation. Although Cepheid variable stars are intrinsically much brighter than RR Lyrae stars, they are often hard to observe because they lie in crowded regions. RR Lyrae stars are in uncrowded
  12. 12. regions, and thus more ideal for observing; however, they are intrinsically a lot less luminous than Cepheids. Thus, there is a limitation as to how far we can actually observe these stars -galaxies in the local group are fine, but not much farther than approximately 2 million light years, and even at that distance the stars are about 25th magnitude! (You can use the magnitude equation to calculate this yourself.)
  13. 13. Visayas The indigenous groups in the Visayas –mostly in Mindoro – are called Mangyan. Again, there are many ethnic groups such as the Tadyawan, Tagbanwa, Palawano, Molbog and Kagayanan. Mindanao There is some differentiation of the indigenous people in Mindanao. The Moro and the Lumad. The Moro practice Islam and the Lumad do not. Moro is Spanish for the word Moor. Lumad means indigenous or native. The Moro include the Maguindanao, Maranao, Tausug and Samal. The Lumad include the Manobo, Bagobo, Tiruray, Tiboli and Mandaya. I've only mentioned a handful of the larger Filipino ethnic groups and Tribes in the Philippines. There are so many groups and tribes with different languages, religions and islands they do still maintain a single national identity - Filipino. It really is the same around the world. In the United States I may be a midwesterner or a Chicagoan. An Illinoisan or a northsider. Despite all these smaller divisions and groupings I'm still considered American! Family includes grandparents, aunts, uncles, cousins, first cousins, second cousins and so on. In my father's hometown in Balete, Aklan he has 4 siblings and 4 first cousins that live within a 1 mile radius of one another. They see and spend time with each other on a regular, usually daily, basis. It is commonplace for at least 3 generations of a family to live in one home or for several generations to live on a single piece of family land. Filipinos go to great lengths to show their hospitality to others. Universally, being a good host by ensuring one's comfort -having enough to eat or drink- is being hospitable. In the Philippines it is not unusual for a host to offer their guest their own bed to sleep in! 0 Speaker: 1 - 1,000 Speakers: 1, 000 or More: EXTINCT ENDANGERED STABLE PHILIPPINE LANGUAGE A Adasen Agta, Alabat Island Agta, Camarines Norte Agta, Casiguran Dumagat Agta, Central Cagayan Agta, Dicamay Agta, Dupaninan Agta, Isarog Agta, Mt. Iraya Agta, Mt. Iriga Agta, Umiray Dumaget Agta, Villaviciosa Agutaynen Alangan NUMBER OF ALTERNATE NAMES SPEAKER STATUS 4,000 30 Itneg Adasen, Addasen Tinguian, Addasen Alabat Island Dumagat Stable Endangered 150 Manide, Abiyan Endangered 610 Casiguran Dumagat Endangered 780 Labin Agta Endangered 0 1,400 6 150 1,500 Dicamay Dumagat Dupaningan Agta, Eastern Cagayan Agta East, Inagta of Mt. Iraya, Itbeg Rugnot, Lake Buhi, Rugnot of Lake Buhi East Mt. Iriga Negrito, San Ramon Inagta, Lake Buhi West Extinct Stable Endangered Endangered Stable 3,000 Umirey Dumagat, Umiray Agta Stable 0 15,000 7,690 Agutaynon, Agutayno Extinct Stable Stable
  14. 14. Alta, Northern Alta, Southern Arta Ata Ati Atta, Faire Atta, Pamplona Atta, Pudtol Ayta, Abellen Ayta, Ambala Ayta, Bataan Ayta, Mag-Anchi Ayta, Mag-Indi Ayta, Sorsogon Ayta, Tayabas B B’laan, Koronadal B’laan, Sarangani Balangao 200 1,000 15 4 1,500 300 1,000 710 3,000 1,660 500 8,200 5,000 18 0 Edimala, Ditaylin Dumagat, Ditaylin Alta Baler Negrito Pugot, Kabuluwen, Kabuluwan, Kabuluen, Kabulowan, Ita, Baluga 150,000 90,800 21,300 Balangingi 80,000 Korondal Bilaan, Tagalagad, Biraan, Baraan, Bilanes Balud, Bilaan, Tumanao Balangaw, Farangao, Balangao Bontoc Western Mindanao, Sulu Archipelago Northeast of Jolo, Islands and Coastal Areas of Zamboanga Coast Peninsula and Basilan Island. Possibly on Luzon and Palawan. Northern Sama on Luzon at White Beach near Subic Bay; Lutangan in Western Mindanao, Olutangga Island. Also in Sabah, Malaysia. Bantoanon Batak Bicolano, Albay Bicolano, Central Bicolano, Iriga Bicolano, Northern Catanduanes Bicolano, Southern Catanduanes Binukid Bolinao Bontoc, Central Buhid Butuanon C Caluyanon Capiznon Cebuano Chavacano, Caviteño Chavacano, Cotabateño Chavacano, Davaweño Chavacano, Ermitaño Chavacano, Ternateño Chavacano, Zamboangueño 200,000 200 1,900,000 2,500,000 234,000 Inati Southern Atta Northern Cagayan Negrito Northern Cagayan Negrito Aburlen Negrito, Ayta Abellen Sambal, Abenlen Ambala Sambal, Ambala Agta Mariveles Ayta, Bataan Sambal, Bataan Ayta Mag-Anchi Sambal Mag-Indi Sambal, Indi Ayta, Baloga Endangered Endangered Endangered Endangered Stable Endangered Endangered Endangered Stable Stable Endangered Stable Stable Endangered Extinct Stable Stable Stable Stable Bikol Rinconada Bicolano Stable Endangered Stable Stable Stable 122,000 Pandan Stable 85,000 Virac Stable 100,000 50,000 540,000 8,000 34,500 Binukid Manobo, Bukidnon, Binokid Bolinao Sambal, Bolinao Zambal, Binubulinao Bontoc Igorot, Bontoc Bukil, Batangan, Bangon Stable Stable Stable Stable Stable 30,000 639,000 21,000,000 Caluyanen, Caluyanhon Capiseño, Capisano Sebuano, Bisayan, Visayan, Binisaya, Sugbuanon, Sugbuhanon Stable Stable Stable 27,841 Caviteño Stable 5,473 Cotabateño Stable 59,058 Davawenyo Zamboanguenyo Stable 0 Ermiteño Extinct 3,750 Ternateño Stable 155,000 Chabakano Zamboangueño Stable Beifang Fangyan, Guanhua, Guoyu, Hanyu, Mandarin, Northern Chinese, Putonghua, Standard Chinese Endangered Minnan, Southern Min Stable Cantonese, Gwong Dung Waa, Yue, Yueh, Yuet Yue, Yueyu Stable Cuyo, Cuyono, Cuyunon, Kuyonon, Kuyunon Stable Davaoeño, Davaweño, Matino Stable 550 Chinese, Mandarin (Philippines) 592,000 Chinese, Min Nan (Philippines) 9,780 Chinese, Yue (Philippines) Cuyonon 123,000 D Davawenyo 147,000 E 3,400,000 English (Philippines) F Finallig 5,000 G Ga'dang 6,000 Gaddang 30,000 Palawan Batak, Tinitianes, Babuyan Stable Eastern Bontoc, Kadaklan-Barlig Bontoc, Southern Bontoc Stable Baliwon, Gadang, Ginabwal Cagayan Stable Stable
  15. 15. Giangan 55,000 H Hanunoo 13,000 Higaonon 30,000 Hiligaynon 8,200,000 I Ibaloi 110,000 Ibanag 500,000 Ibatan 1,350 Ifugao, Amganad 27,000 Ifugao, Batad 43,000 Ifugao, Mayoyao 30,000 Ifugao, Tuwali 30,000 Ilocano 9,100,000 Ilongot 50,800 Inabaknon 21,400 Inakeanon 520,000 Inonhan 85,800 Iraya 10,000 Isinai 5,520 Isnag 30,000 Itawit 134,000 Itneg, Banao 3,500 Itneg, Binongan 7,500 Itneg, Inlaod 9,000 Itneg, Maeng 18,000 Itneg, Masadiit 7,500 Itneg, Moyadan 12,000 Ivatan 35,000 I-wak 3,260 K Kagayanen 30,000 Kalagan 21,400 Kalagan, Kagan 6,000 Kalagan, Tagakaulu 83,000 Kalinga, Butbut 8,000 Kalinga, Limos 20,000 Kalinga, Lower 11,200 Tanudan Kalinga, Lubuagan 14,000 Kalinga, Mabaka Not Available Valley Kalinga, 1,500 Madukayang Kalinga, Southern 13,000 Kalinga, Upper 3,000 Tanudan Kallahan, Kayapa 15,000 Kallahan, Keley-i 8,000 Kallahan, Tinoc Not Available Kamayo 7,570 Kankanaey 150,000 Kankanay, 70,000 Northern Karao 1,400 Karolanos 15,000 Kasiguranin 10,000 Katabaga 0 Kinaray-a 378,000 M Magahat 7,570 Maguindanaon 1,000,000 Malaynon 8,500 Mamanwa 5,150 Mandaya, 19,000 Cataelano Mandaya, Karaga 3,000 Mandaya, Sangab 7,500 Manobo, Agusan 60,000 Manobo, Ata 26,700 Atto, Bagobo, Clata, Eto, Guanga, Gulanga, Jangan Stable Hanonoo Misamis Higaonon Manobo Hiligainon, Ilogo, Ilonggo Stable Stable Stable Benguet-Igorot, Ibadoy, Ibaloy, Igodor, Inibaloi, Nabaloi Ybanag Babuyan, Ibataan, Ivatan Amganad, Ifugaw Batad, Ifugaw Ifugaw, Mayoyaw, Mayoyao Gilipanes, Ifugaw, Kiangan Ifugao, Quiangan Ilokano, Iloko Bugkalut, Bukalot, Lingotes Abaknon, Abaknon Sama, Capuleño, Kapul, Sama Aklan, Aklano, Aklanon, Aklanon-Bisayan, Panay Loocnon, Looknon, “Unhan” Stable Stable Stable Stable Stable Stable Stable Stable Stable Stable Stable Stable Stable Stable Stable Stable Stable Stable Stable Stable Stable Stable Stable Stable Inmeas, Insinai, Isinay, Isnay Dibagat-Kabugao-Isneg, Isneg, Maragat Itawes, Itawis, Tawit Banao, Banaw, Itneg, Tinggian, Tinguian Tingguian, Tinguian Tinggian, Tinguian Luba-Tiempo Itneg, Southern Itneg Tinggian, Tinguian Itbayaten, Basco Ivatan, Southern Ivatan Iwaak Cagayano, Kagay-Anen, Kinagyanen Kaagan, Kagan Kalagan Tagakaolo Butbut Limos-Liwan Kalinga, Northern Kalinga Stable Stable Stable Stable Stable Stable Lower Tanudan Stable Stable Kal-Uwan, Mabaka, Mabaka Itneg Majukayong Stable Tinglayan Kalinga Stable Upper Tanudan Stable Akab, Ikalahan, Kalangoya-Ikalahan, Kalanguya, Kalkali, Kayapa Antipolo Ifugao, Hanalulo, Keley-i, Keley-i Kalanguya, Keleyqiq Ifugao Tinoc Kalangoya Stable Stable Central Kankanaey, Kankanai, Kankanay Stable Stable Sagada Igorot, Western Bontoc Stable Karaw Stable Stable Stable Extinct Stable Casiguranin Antqueño, Ati, Hamtiknon, Hinaray-a, Karay-a, Kiniray-a, Panayano, Sulud Ata-Man, Bukidnon Magindanaw, Maguindanaw Mamanwa Negrito, Minamanwa Stable Stable Stable Stable Cateelenyo Stable Carraga Mandaya, Manay Mandayan, Mangaragan Mandaya Sangab Agusan Ata of Davao, Atao Manobo, Langilan Stable Stable StableE Stable
  16. 16. Manobo, Cinamiguin Manobo, Cotabato Manobo, Dibabawon Manobo, Ilianen Manobo, Matigsalug Manobo, Obo Manobo, Rajah Kabunsuwan Manobo, Sarangani Manobo, Western Bukidnon Mansaka Mapun 60,000 Cinamiguin, Kamigin, Kinamigin Stable 30,000 Tasaday, Blit Stable 10,000 Debabaon, Bidabaon, Mandaya Stable 14,600 Ilianen Stable 30,000 Matig-Salug Manobo Stable 60,000 Bagobo, Kidapawan Manobo, Obo Bagobo Stable 7,570 Rajah Kabungsuan Manobo Stable 58,000 Governor Generoso Manobo Stable 19,000 Ilentungen, Kiriyenteken, Pulangiyen Stable 57,800 Mandaya Mansaka Bajau Kagayan, Cagayan, Cagayan De Sulu, Cagayano, Cagayanon, Jama Mapun, Kagayan, Orang, Sama Mapun Maranaw, Ranao Masbateño, Minasbate Molbog Palawan Stable Brooke’s Point Palawan, Palawan, Palawanun, Palaweño Stable Palawanen, Palaweño, Quezon Palawano Stable 40,600 Maranao 1,142,000 Masbatenyo 600,000 Molbog 6,680 P Palawano, Brooke's 14,400 Point Palawano, Central 12,000 Palawano, 12,000 Southwest Pampangan 2,890,000 Pangasinan 1,500,000 Paranan 16,700 Porohanon 23,000 R Ratagnon 2 Romblomanon 200,000 S Sama, Central 90,000 Sama, Pangutaran 35,200 Sama, Southern 200,000 Sambal, Botolan 32,900 Sambal, Tina 70,000 Sangil 15,000 Sangir 200,000 Sinauna 2,530 Sorsogon, Masbate 85,000 Sorsogon, Waray 185,000 Spanish 2,660 Subanen, Central 140,000 Subanen, Northern 10,000 Subanon, 20,000 Kolibugan Subanon, Western 75,000 Subanun, Lapuyan 25,000 Sulod 14,000 Surigaonon 1,000,000 T Tadyawan 4,150 Tagabawa 43,000 Tagalog 28,000,000 Tagbanwa 10,000 Tagbanwa, 10,000 Calamian Tagbanwa, Central 2,000 Tausug 1,300,000 Tawbuid, Eastern 7,190 Tawbuid, Western 6,810 T’boli 95,300 Tiruray 50,000 W Waray 2,600,000 Y Yakan 106,000 Stable Stable Stable Stable Stable Pampanga, Tarlac, and Bataan Provinces (Luzon). United States Palawenyo, Palanan Camotes Island Stable Stable Stable Stable Aradigi, Datagnon, Lactan, Latagnun, Latan Romblon Endangered Stable Central Sinama, Samal, Siasi, Sama, Sinama Sindangan Subanun Tuboy Subanun Stable Stable Stable Stable Stable Stable Stable Stable Stable Stable Stable Stable Stable Calibugan, Kalibugan, Kolibugan Stable Siocon Lapuyen, Margosatubig, Subanen Bukidnon, Mondo Stable Stable Stable Stable Balaban, Pula, Tadianan Tagabawa Bagobo, Tagabawa Manobo Stable Stable Stable Stable Sama Sibutu’, Sama Tawi-Tawi Aeta Negrito, Ayta Hambali, Botolan Zambal Sambali, Tina Sanggil, Sangire Sangi, Sangih, Sangihe, Sangirese Hatang-Kayey, Remontado Agta Northern Sorsogon, Sorsogon Bicolano Bikol Sorsogon, Gubat Sorsogon, Southern Sorsogon Aborlan Tagbanwa, Apurawnon, Tagbanua Stable Bahasa Sug, Moro Joloanon, Sinug, Sulu, Suluk, Tawsug, Taw Sug Bangon, Barangan, Batangan, Binatangan, Fanawbuid, Suri, Tabuid, Taubuid, Tiron Batangan Taubuid, Fanawbuid, Western Tawbuid T’boli, Tagabili, Tiboli Teduray, Tirurai Stable Stable Stable Stable Stable Stable Binisaya, Samar-Leyte, Samaran, Samareño, Waray Stable Tacan Stable
  17. 17. Yogad 16,000 Stable