Difference between revisions of "Reach for the Stars"
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You are asked to use information which includes the following: | You are asked to use information which includes the following: | ||
− | *Hertzsprung-Russell diagrams | + | *Hertzsprung-Russell diagrams (great website to learn about stars, basics) |
+ | -http://aspire.cosmic-ray.org/labs/star_life/starlife_main.html | ||
*Spectra | *Spectra | ||
*Light curves | *Light curves | ||
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*Identify and be knowledgeable about multi-wavelength images of the different stages of stellar evolution listed above | *Identify and be knowledgeable about multi-wavelength images of the different stages of stellar evolution listed above | ||
*'''Identify, know the location, be knowledgeable about, and/or answer questions relating to the stellar evolution of the | *'''Identify, know the location, be knowledgeable about, and/or answer questions relating to the stellar evolution of the | ||
− | following objects...''' | + | following objects...''' |
==Pictures== | ==Pictures== |
Revision as of 00:52, 11 December 2012
This event rotates with Solar System. It was an event during the 2011-2012 season and will return for the 2012-2013 season.
For the 2011-2012 rules:2011-2012 Rules
2012-2013 Rules
For the 2012-2013 season, each team will be allowed to bring 2 double-sided 8.5 x 11" sheets of notes along with a clipboard and red filtered flashlight. You may put anything on this paper such as text, illustrations, tables, and pictures.
Stars
These are the stars from the 2012-2013 list in alphabetical order:
Aldebaran (α Tauri, "the Bull's Eye")- A K5III star (giant, not main sequence) with an apparent magnitude of 0.87, Aldebaran is the 13th brightest star in the nighttime sky. It is around 65 LY away, and it has a white dwarf companion Aldebaran B, with a classification of M2V. The name Aldebaran is from Arabic for "the follower" (because it follows the Pleiades across the night sky). The nickname "the Bull's eye" comes from its bright orange color and its position in the "Bull's head" asterism.
Algol (β Persei, the "Demon Star")- A triple star system, with Algol A as a B8V star, Algol B as a K0-2III star, and Algol C as a A5V star. Combined, it has an apparent magnitude of 2.1, which drops to 3.4 every 3 days or so when Algol A is eclipsed by Algol B (called an eclipsing binary). "Algol" is from Arabic for "head of the ghoul"- they saw the star as the head of Medusa (the Gorgon who turned anyone she looked at into stone).
Altair (α Aquilae)- The 12th brightest star in the sky with an apparent magnitude of 0.77, Altair is one of the vertices of the Summer Triangle (along with Vega and Deneb). It is flattened at the poles due to its high rotation speed. The name Altair comes from a shortened version of the Arabic phrase "the flying eagle". Altair is a A7V star and it's 16.8 LY away.
Antares (α Scorpii)- Antares is a M1.51 star (a supergiant), with an apparent magnitude ranging from 0.9 to 1.8 (it's a variable star). The ancient Greek for "against Mars" (roughly, anti-Ares) became the modern day name of Antares. About 600 LY away, it is also the 16th brightest star in the sky, even though a large portion of its emitted energy is in the infrared wavelengths. Its companion Antares B is a B2.5V star.
Arcturus (α Bootïs)- With an apparent magnitude of -0.05 (can vary by 0.04), Arcturus is the fourth brightest star in the nighttime sky. However, it is less bright than Alpha Centauri A and B combined, which means that it is the third brightest individual star in the night sky. Arcturus might actually be a binary star with a companion around 20 times or so dimmer, at the very edge of our ability to detect it. Arcturus is about 36.7 LY away and is a K1.5III star. The name is derived from Arabic for "bear guard", because it is close to both Ursa Major and Ursa Minor.
Betelgeuse (α Orionis)- Betelgeuse (yes, pronounced beetle-juice) is a M2I red supergiant about 600 LY away. It is most likely a young star evolving quite rapidly. Betelgeuse is usually the second brightest star in Orion with an apparent magnitude of around 0.58, but since it's a variable star, Betelgeuse is sometimes brighter than Rigel. Also, it is one of the vertices of the Winter Triangle, along with Sirius and Procyon. "Betelgeuse" comes from a mistranslation of the Arabic phrase for "hand of the central one". Betelgeuse is considered very likely to go supernova after its red giant phase.
Capella (α Aurigae)- Part of the Hyades moving group, Capella is the 6th brightest star in the night sky and the 3rd brightest in the northern celestial hemisphere. It is actually a "star system" of 4 stars in 2 pairs. The first pair are G8III and K0III stars (probably previously A-class stars that have now moved off the main sequence and are becoming red giants) while the second pair consists of 2 small, cool, dim red dwarfs. Combined, these stars have an apparent magnitude of 0.08; additionally, they are 42.2 LY from Earth. There are lots of x-rays being emitted from the corona of the largest star. Capella means "she-goat."
Castor & Pollux (α Geminorum)- Castor is the second brightest star in the constellation Gemini, named after one of the twin sons of the Greek god Zeus. Castor is actually a sextuple star system, with two pairs of A-class stars (1V and 2V) and M-class stars orbited by two more M-class dwarfs. The apparent magnitude can be either 1.96 or 2.91, depending on which of the A-class stars is measured.
Deneb (α Cygni)- One of the vertices of the Summer Triangle, Deneb is an A2I star about 1550 LY away. With an apparent magnitude of 1.25, Deneb is actually the farthest 1st-magnitude star from Earth. It will probably become a supernova in a few million years. Because Deneb is the tail of Cygnus, the swan, its Arabic name is quite fittingly, "tail".
Gliese 581- Gliese 581 is a red dwarf, M3V star about 20 LY away. The star has an apparent magnitude between 10.56 and 10.58 and is located in the constellation Libra. The star is well known for its planet Gliese 581 g, thought to be in the habitable zone of its star, but the planet's existence is disputed.
HL Tau- This very young star is dim and located 520 light years away in the constellation of Taurus. The star has a very large and bright "accretion disk", which is a disk of gas and dust surrounding the star. Because of this, it was a good candidate to witness a planet in forming, called a "protoplanet". After a few studies, it was revealed that there was a ball of Gas and Dust 14-times the mass of Jupiter -- A planet forming. It is the youngest planet ever discovered.
Mizar & Alcor- The sextuple system Mizar and Alcor is located on the handle of the Big Dipper Asterism in Ursa Major. Mizar is actually made up of two binary systems, while Alcor is a binary system itself. The stars have an apparent magnitude of 2.23. It looks like a single star at a glance, but a person with keen eyesight can see both Mizar and Alcor. For this reason, it has been important to navigators and explorers throughout history.
Polaris (α Ursae Minoris, "North Star", the "Pole Star")- Polaris is an important star for navigation, however, it is only approximate North. Polaris A is a F7I-II star, while companions Polaris B and Ab are a F-class main sequence star and a dwarf, respectively (there are also 2 farther stars, Polaris C and D). Polaris may be part of a loose cluster of A- and F-class stars.
Procyon (α Canis Minoris)- Procyon is the 7th brightest star in the nighttime sky with an apparent magnitude of 0.34. Procyon is a binary star system (Procyon A is a F5IV-V star, Procyon B is a white dwarf) and it's also a vertex of the Winter Triangle. Procyon forms a prominent equilateral triangle with Sirius and Betelgeuse. In Greek, Procyon means "preceeding the dog", because it rises before Sirius.
Proxima Centauri- At only 4 light years, Proxima centauri is the nearest star to the sun. It is a type-M red dwarf star, and despite its distance, it is too dim to see with the naked eye, at magnitude 11.05. Proxima Centauri is part of a triple star system with its brighter neighbor Alpha Centauri A and B. It is a flare star, a variable type that changes brightness drastically.
Regulus (α Leonis)- Around 77.5 LY away, Regulus is a quadruple star system- Regulus A is a B7V star with a white dwarf companion, while Regulus B and C are dim main sequence stars (a K1-2V star and a M5V star, respectively). Regulus A is a young star that spins very rapidly and it has a magnitude of 1.35. The name comes from Latin for "little king" or "prince".
Rigel (β Orionis)- Named in Arabic "left foot of the central one", Rigel is an important star for navigation. Somewhere between 700 and 900 LY away, Rigel is also known as the most luminous star in the nearby Milky Way. Most of the time, it is the brightest star in Orion, but Betelgeuse can be brighter because it is a variable star. Rigel is known to be a triple star system, however, it may in fact be a quadruple star system. The most prominent star is a B8I star with an apparent magnitude of 0.11.
Sirius (α Canis Majoris, the "Dog Star")- Sirius is the brightest star in the night sky, with an apparent magnitude of -1.47. The binary star system consists of Sirius A (an A1V star) and Sirius B (which used to be even larger than Sirius A but has evolved into a white dwarf). Sirius can be seen up to 73 degrees north or south of the equator, and it's one of the vertices of the Winter Triangle, along with Procyon and Betelgeuse. The nickname "Dog Star" comes from the constellation Sirius is in: Canis Major, the Big Dog. Sirius is about 8.6 LY away.
Spica (α Virginis)- A B1III-IV star with an apparent magnitude varying between 0.92 and 1.04 over a 4-day period of time. Spica is a binary star system (companion Spica B is a B2V star) about 260 LY away. Its name comes from Latin for "Virgo's ear of grain".
Vega (α Lyrae)- Vega is the 5th brightest star in the night sky and the 2nd brightest in the northern celestial hemisphere. It is an A0V star approximately 25 LY away that is flattened at the poles due to its high rotation speed. Vega is 1/10 the age of the Sun, but it's already halfway through its life as a main sequence star. There is the possibility that Vega has its own little solar system of sorts- it may have orbiting planets. Vega is a vertex of the Summer Triangle (the other vertices are Altair and Deneb). The name is derived from the Arabic phrases for either "falling eagle" or "swooping vulture".
γ Velorum Far in the southern sky lies a very interesting star - Gamma Velorum. It is an extremely luminous Wolf-Rayet star, which is a type of massive star that is losing mass due to a stellar wind at a violent rate. Currently, Gamma Velorum is about 10 times the mass of the sun, it was initially over 20 times heavier than the sun, but has been losing mass rapidly. It orbits another highly-luminous blue supergiant. From Earth, it appears at apparent magnitude 1.27.
Deep Space Objects
These are the DSOs (Deep Sky Objects) from the 2012-2013 list in alphabetical order:
30 Doradus-
Cassiopeia A- Cassiopeia A is a supernova remnant about 11,000 LY away. The supernova itself happened around 1667 (the most recent supernova in the Milky Way visible to the naked eye), and resulted from the collapse and explosion of a large star. Cassiopeia A emits lots of radio waves, but is very hard to see with the naked eye at the present day.
Tycho's Star (Cassiopeia B)- A supernova remnant, left over from a supernova detected in November 1572 which remained highly visible for 2 years, then faded. The supernova resulted from a white dwarf accumulating too much matter and exploding. It is called Tycho's SNR after the astronomer Tycho Brahe, who was the most accurate observer of the supernova itself.
CoRoT-2A-
Crab Nebula (M1, NGC 1952)- A supernova remnant in the constellation Taurus, M1 is the result of a 1054 supernova where a supergiant star collapsed inwards and subsequently exploded. At the very center is the Crab Pulsar, a rapidly rotating neutron star that emits pulses of x-rays and gamma rays. In fact, the Crab Pulsar is the strongest persistent source of x-rays and gamma rays in the sky.
Cygnus X-1-
Eta Carinae-
G359.23-0.82-
Geminga-
Globular Cluster (M13, NGC 6205)- A globular cluster (hence the name) about 25,100 LY away and 145 LY across in the constellation Hercules. M13 has several hundred thousand stars, but is barely visible from Earth, with an apparent magnitude of 5.8. Its brightest star is V11, which has an apparent magnitude of 11.95.
Hyades Star Cluster- The Hyades are the closest open cluster to us at 151 LY away, located in the constellation Taurus. The 4 brightest stars in the Hyades (formerly A-class stars, now off the main sequence) form a V shape along with Aldebaran. It could share a common origin with the Beehive Cluster (M44). The name is from ancient Greek mythology- Hyades was the collective name of several weeping sisters who were turned into stars and therefore associated with rain.
Milky Way Galaxy ("The Galaxy")- A barred spiral galaxy in the Local Group (which, in turn, is in the Virgo Supercluster) about 100,000 LY in diameter and 1,000 LY thick. Of the 200-400 billion stars in this galaxy, most are red dwarfs. The oldest ones are 12.8-14.4 billion years old. The galactic center is in the general direction of the constellation Sagittarius- in fact, Sagittarius A* is a supermassive black hole at the center of the Milky Way. It could collide with the Andromeda Galaxy in 3-4 billion years. The Milky Way can be seen as far north as Cassiopeia and as far south as Crux (the Southern Cross).
NGC 7000-
NGC 7293-
Orion Nebula (M42, NGC 1976)- A part of a larger nebula (the Orion Molecular Cloud Complex), the Orion nebula is about 1270 LY away and 24 LY across. It's the middle star in Orion's sword, with large O-class stars in the center. M42 has protoplanetary disks, brown dwarfs, and large supersonic "bullets" of gas. The Orion Nebula is quite prominent on infrared because of all the stars that are being formed. In 100,000 years, it will be wisps of gas around hot, new stars, like the Pleiades.
Pleiades (M45, Maia Nebula)- Another open cluster in the constellation Taurus; one of the closest to Earth at about 440 LY away. Most of the stars in M45 are hot, blue stars formed in the last 100 million years or so, but there are also some brown dwarfs. The cluster will survive for about another 250 million years, then be dispersed by gravity. The name Pleiades is from Greek for either "sailing ones", "many", or "flock of doves".
Ring Nebula (M57, NGC 6822)- A planetary nebula about 2300 LY away in the constellation Vega with apparent magnitude 9. The central star is evolving into a white dwarf (right now, it mainly consists of carbon and oxygen).
Sagittarius A*- Most likely a supermassive black hole at the center of the Milky Way about 44 million km in diameter, Sagittarius A* is a source of radio waves. It is about 26,000 LY away.
SN1993J-
SS433-
Vela Supernova Remnant
Harvard Spectral Classification
There are 7 spectral Classes (O,B,A,F,G,K,M). This order is based on decreasing surface temperature. A Class stars have the strongest Hydrogen lines, while M Class stars have the weakest hydrogen lines. Each class is then subdivided into 10 subdivisions (0-9).
The following is a table with properties of each of the spectral classes.
Type | Temperature (Kelvin) | Color | Hydrogen |
---|---|---|---|
O | 30,000-60,000 | Blue | Weak |
B | 10,000-30,000 | Blue-White | Medium |
A | 7,500-10,000 | White | Strong |
F | 6,000-7,500 | White | Medium |
G | 5,000-6,000 | Yellow | Weak |
K | 3,500-5,000 | Yellow-Orange | Very Weak |
M | 2,000-3,500 | Red | Very Weak |
The following is the class of each of the stars on the list:
Class O- None on the list
Class B- Rigel, Spica, Regulus, Algol, and Spica
Class A- Vega, Sirius A, Deneb, Altair, and Castor
Class F- Procyon, and Polaris
Class G- The Sun, and Capella
Class K- Arcturus, Aldebaran, and Pollux,
Class M- Betelgeuse, Wolf 359, and Antares
Yerkes Spectral Classification
The Yerkes Spectral Classification is based on luminosity and temperature. It is also known as luminosity classes. There are seven main luminosity classes:
Type Ia- Bright Supergiants
Type Ib- Normal Supergiants
Type II- Bright Giant
Type III- Normal Giant
Type IV- Sub-Giants
Type V- Main Sequence
Type VI- Sub-Dwarf
VII- White Dwarf
Galaxies
There are three main types of galaxies: Spiral, Elliptical, and Irregular. However, in the 2013 rules, there are no galaxies on the list. Nevertheless, we have here a short description of each type of galaxy.
Spiral Galaxies
Spiral Galaxies are named so because they have prominent spiral arms and a central "galactic nucleus" or central bulge.
Spiral Galaxies also have a very large rate of star formation in the spiral arms of the galaxy. Also, almost all spiral galaxies have a galactic halo that surrounds the galaxy. These halos contain stray stars and globular clusters. It is also theorized that many spiral galaxies have supermassive black holes at the center of the galaxy. Our own galaxy, The Milky Way, is a spiral galaxy, and is also theorized to have a supermassive black hole at its center, called Sgr A*. There is also a sub-division of spiral galaxies, known as barred-spiral galaxies. Barred-spirals have a central bar, and then have spiral arms shooting off at each end of the bar.
The spiral galaxies on the list for 2009 are:
- M31 Andromeda Galaxy (in Andromeda)
- M51 Whirlpool Galaxy (In Canes Venatica)
- Milky Way Galaxy (Barred-Spiral)
Elliptical Galaxy
Elliptical Galaxies appear just like they sound- they are elliptical/ spherical. Elliptical Galaxies contain mostly old Population II stars, and also, they have a very low rate of star formation because there is barely any interstellar matter in elliptical galaxies. There is the least amount of elliptical Galaxies in the known Universe.
The Elliptical Galaxies on the list for 2009 are:
-M84 (in Virgo)
Concerning M84, some astronomers believe that it actually may be a Lenticular Galaxy (which is a half-way point between a Spiral galaxy and an Elliptical galaxy)
Irregular Galaxies
Irregular also appear just how they sound- they are without a definite shape. They are normally formed by Spiral or
Elliptical Galaxies that have been deformed by different forces- such as gravity. They contain a lot of interstellar matter.
The Irregular Galaxies on the list for 2009 are:
-Large Magellanic Cloud (in Dorado and Mensa)
-Small Magellanic Cloud (in Tucana)
Star Identification
The best way to study for the first part of the event is to go outside and look at the sky. If you are not familiar with the constellations this is a great way to learn them. Look up into the sky and use a star chart to find a few constellations and stars. Doing this even a few times a month really pays off.
Another great way to study for this event to get you ready to go outside is to make flash cards with the constellation on the front and the name and the deep sky objects on the back.
It is helpful if you can relate easy-to-find constellations such as Orion or Ursa Major (Big Dipper) to the constellations around them. This guides you to the constellation via others, rather than having to rely only on the shape. On your reference sheet, you may want to include a section about how to find the constellations you have trouble with.
Stellar Information
"Students will demonstrate an understanding of the basic concepts of mathematics and astrophysics relating to stellar evolution."
For the second part of the event you have to know about the general characteristics of stars, galaxies, star clusters, etc. You must be able to figure out a star's spectral class, surface temperature, and evolutionary stage (i.e. giant, supergiant, main sequence, white dwarf) by reading an H-R diagram.
Another thing you should do is learn the life cycles of various types of stars. Look at some of the pictures below and try to put them in order.
You should also be familiar with redshift and blueshift and how they are related to the (theoretical) creation of the universe, something that many people overlook.
Another aspect of the event that is new for 2009 is that you must be able to label a model of the sun and be familiar with its spectral class and placement on an H-R diagram as well as other general characteristics.
You are asked to use information which includes the following:
- Hertzsprung-Russell diagrams (great website to learn about stars, basics)
-http://aspire.cosmic-ray.org/labs/star_life/starlife_main.html
- Spectra
- Light curves
- Kepler's laws
- Energy transfer
- Impulse-momentum
- Circular motion
- Radiation laws (Wien's and Stefan-Boltzmann)
- Period-luminosity relationship
- Stellar magnitudes and classification
- Parallax
- Slides
- Photographs
- Star charts and animations
You may also be asked to complete activities which include:
- Determine answers relating to stellar birth
- Determine answers relating to stellar evolution and the Hertzsprung-Russell diagram
- Determine answers relating to the motions and evolution of star systems
- Identify and be knowledgeable about multi-wavelength images of the different stages of stellar evolution listed above
- Identify, know the location, be knowledgeable about, and/or answer questions relating to the stellar evolution of the
following objects...
Pictures
Know these pictures: (Harvard's Chandrasekhar X-Ray Observatory and Hubble Space Telescope are to be credited with these images)
Cas A (Cassiopeia A) - super nova remnant
(infrared, optical, radio, and X-ray images)
M1 (Crab Nebula) - Nebula
(infrared, optical, radio, and X-ray images)
Crab Pulsar - fastest pulsar known (30 pulses per second)
Orion Trapezium Cluster - 4 hot young stars in an open cluster in the Orion Nebula
M57 (Ring Nebula) - Planetary Nebula (optical, infrared)
File:M57optical1.jpg File:M57infrared.jpg
Familiarize yourself with these pictures, print them out, or put them on your laptop. You may also need to know about other pictures and the pictures of the stars on the list.
Helpful Tips
Identification certainly is not the most important part of this event but I have found it is it easiest way to begin your study. For the rest of the event, you must study the things mentioned in the table above (make it a checklist if you want). This task is facilitated by Astronomy Today--I have found all the information I have ever needed, either during a test or after a test, in that book.
Sometimes, the test will use a StarLab or planetarium for the identification portion. I would advise putting some time in to familiarize yourself with how the skies look on it.
Also, there is always a chance that a bad star map may be used, so make sure to get yourself accustomed to anything that may be thrown at you.
The best way to study for the identification part, is not only maps, but actually going outside and finding constellations and stars in the night sky. Not only is star-gazing fun, but it is one of the best ways to learn the location of the constellations and the stars that are on the list.
Sample Tests
Identification practice: Reach for the Stars Test (2009)
Also be sure to check out the Reach for the Stars Test Exchange.
Useful Resources
Astronomy Today by Eric J. Chaisson [1] [2]
Foundations of Astronomy by Michael A. Seeds [3] [4] [5] [6]
New York Coaches Conference [7]