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.
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
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)
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),
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
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
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
Planetary Nebula Mz 3 (Courtesy Hubble Heritage Team
Energy production in the star will eventually stop as the Heand Hfusing shells work their way through the star. At this stage,
envelopes and the atmosphere are extremely unstable. Large
pulsations in the star have driven almost half of the star's
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.
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
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
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.
(Back to top)
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.
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.
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)
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!
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
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.
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
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.
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 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
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
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 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.
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
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.)
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.
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
Agta, Alabat Island
Agta, Mt. Iraya
Agta, Mt. Iriga
Itneg Adasen, Addasen Tinguian, Addasen
Alabat Island 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
Umirey Dumagat, Umiray Agta
Edimala, Ditaylin Dumagat, Ditaylin Alta Baler Negrito
Pugot, Kabuluwen, Kabuluwan, Kabuluen, Kabulowan, Ita, Baluga
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.
Northern Cagayan Negrito
Northern Cagayan Negrito
Aburlen Negrito, Ayta Abellen Sambal, Abenlen
Ambala Sambal, Ambala Agta
Mariveles Ayta, Bataan Sambal, Bataan Ayta
Mag-Indi Sambal, Indi Ayta, Baloga
Binukid Manobo, Bukidnon, Binokid
Bolinao Sambal, Bolinao Zambal, Binubulinao
Bontoc Igorot, Bontoc
Bukil, Batangan, Bangon
Sebuano, Bisayan, Visayan, Binisaya, Sugbuanon, Sugbuhanon
Beifang Fangyan, Guanhua, Guoyu, Hanyu, Mandarin, Northern Chinese, Putonghua, Standard
Minnan, Southern Min
Cantonese, Gwong Dung Waa, Yue, Yueh, Yuet Yue, Yueyu
Cuyo, Cuyono, Cuyunon, Kuyonon, Kuyunon
Davaoeño, Davaweño, Matino
Chinese, Min Nan
Palawan Batak, Tinitianes, Babuyan
Eastern Bontoc, Kadaklan-Barlig Bontoc, Southern Bontoc
Baliwon, Gadang, Ginabwal