# Reach for the Stars

 This page is incomplete. It does not cover all aspects of this subject. Please keep this in mind when reading the page and add relevant information if possible.

 Reach for the Stars Earth Science & Study Event Forum Threads 2017 2016 2013 2012 2009 Tests 2017 2016 Test Exchange Archive There are no images available for this event Question Marathons 2017 Division B Champion Daniel Wright Junior High School This event was not held last year in Division C

Reach for the Stars is a Division B event. This event rotates every two years with Solar System. It was previously an event during the 2011-2012 season, 2012-2013 season, 2015-2016 season, and 2016-2017 season.

For information pertaining to the 2011-2012 rules, see Reach for the Stars 2011-2012.

## 2016-2017 Rules

Each team is allowed to bring 2 double-sided 8.5" x 11" sheets of notes, and may be asked to bring a clipboard and red filtered flashlight. You are allowed to put anything on this paper, such as text, illustrations, tables, and pictures. Calculators are also allowed unless told otherwise by event supervisors.

## Part I

In Part I, students are asked to identify a specified list of stars, constellations, and deep sky objects (DSOs), which may appear on star charts, HR diagrams, planetariums, or other forms of display. Teams must also be knowledgeable about the evolutionary stages of the stars and deep space objects on the list.

### Star Charts

During competitions, the star charts given can be from any location on Earth, in any season and at any time of the night. Therefore, it is crucial to be able to recognize stars and constellations in any orientation.

Below are three star charts that together cover all Stars and Deep Sky Objects from the 2017 Reach for the Stars list. Mizar and Alcor are binary systems, while 30 Doradus is in the Large Magellanic Cloud.

 NYC, Summer Solstice
 NYC, Winter Solstice
 Sydney, Summer Solstice

### Stars

These are the stars from the 2016-2017 list (not in alphabetical order). With multiple-star systems, the Apparent/Absolute Magnitude is the combined Apparent/Absolute Magnitude of the stars:

2017 Stars
Name Images Spectral Type Constellation Magnitude Distance Coordinates External Links
Apparent Absolute Right Ascension Declination
Altair A7V Aquila 0.76 2.22 16.73 ly 19h 50m 47s +08° 52′ 06″
Main sequence star.
Capella K0III/G1III Auriga 0.08* -0.48 42.9ly 05h 16m 41s +45° 59′ 53″
RS CVn Variable Star, a close binary system whose apparent magnitude varies from +0.03 to +0.16.
Arcturus K0III Boötes -0.05 -0.30 36.7 ly 14h 15m 40s +19° 10′ 56″
Red giant star.
Sirius A1Vm/DA2 Canis Major -1.46 1.42 8.60 ly 06h 45m 09s −16° 43′ 06″
Brightest star in the night sky. A binary system with Sirius A, a main sequence star, and Sirius B, a white dwarf with Apparent Magnitude 8.44 and Absolute Magnitude 11.18. The name "Sirius" is derived from the Ancient Greek "Seirios", meaning "glowing" or "scorcher".
Procyon F5IV-V Canis Minor 0.34 2.66 11.5 ly 07h 39m 18s +05° 13′30″
Main sequence star with faint white-dwarf companion.
Deneb A2Ia Cygnus 1.25 -8.38 802 ± 66 pc 20h 41m 25.9s +45° 16′ 49″
Blue-white Supergiant.
Castor Gemini 51 ly 07h 34m 36s +31° 53′ 18″
Triple Star system.
Pollux K0III Gemini 1.14 1.08 33.8 ly 07h 45m 19s +28° 01′ 34″
Giant star.
Regulus B8 IVn Leo 1.40 -0.52 79.3 ly 10h 08m 22s +11° 58′ 02″
Four star system. Values above are only for Regulus A.
Vega A0Va Lyra -0.02-0.07 (0.026) +0.582 25 ly 18h 36m 56s +38° 47′ 01″
Suspected Delta Scuti Variable. Northern pole star around 12,000 BC.
Zeta Ophiuchi O9.5 V Ophiuchus 2.57 -4.2 366 ly 16h 37m 10s –10° 34′ 02″
Blue main-sequence star at the start of its life.
Betelgeuse M1-M2 Ia-ab Orion -5.85 643 ± 146 ly 05h 55m 10s +07° 24′ 25″
Semiregular Variable Star.
Rigel B8 Ia Orion 0.13 -7.84 860 ± 80 ly 05h 14m 32s −08° 12′ 06″
Blue Supergiant with Blue main-sequence companion.
Algol B8V/K0IV Perseus -0.07 90 ± 3 ly 03h 08m 10s +40° 57′ 20.3280″
Multiple star system with a pair of eclipsing Variable stars. Counter-intuitively, the lower-mass star is leaving the main-sequence earlier.
Antares M1.5Iab+B2.5V Scorpius 0.6-1.6 -5.28 550 ly 16h 29m 24.5s −26° 25′ 55″
Red Supergiant with Orange main-sequence star companion.
Aldebaran K5III Taurus -0.86 -0.64 65ly 04h 35m 55s +16° 30′ 33.5″
Orange Giant Star.
Mizar A2Vp Ursa Major 2.27 0.33 86 ± 4 ly 13h 23m 55.5s +54° 55′ 31″
Visual double with Alcor.
Alcor A5Vn Ursa Major 3.99 2.00 81.6 ly 13h 25m 13.5s +54° 59′ 17″
Visual double with Mizar.
Polaris F7Ib/F6V Ursa Minor 1.98 -3.6 323-433 ly 02h 31m 49.1s +89° 15′ 50.8″
Current Northern pole star; Multiple Star system with Yellow Supergiant orbiting a smaller companion; Cepheid Variable star.
Spica B1 III-IV/B2 V Virgo 0.97 -3.55 250±10 ly 13h 25m 11.6s −11° 09′ 40.8″
Binary star system with a blue giant (beta cepheid variable) and a blue main-sequence star; a spectroscopic binary and rotating ellipsoidal variable; 22400 Kelvin.

### Deep Sky Objects

These are the DSOs (Deep Sky Objects) from the 2016-2016 list (not in alphabetical order):

• NGC 7293 (Helix Nebula):
• NGC 3603:
• NGC 3372:
• Cassiopeia A:
• Tycho's SNR:
• Cygnus X-1: Cygnus X-1 is a source of x-rays in the constellation Cygnus. It is the first widely accepted black hole to be an x-ray source such as itself. It was discovered in 1964 and is located about 6,070 light years from the sun. Cygnus X-1 is a member of a high-mass X-ray binary system. It is about 5 million years old and rotates once every 5.6 days.
• 30 Doradus: Located in the constellation of Dorado, 30 Doradus is an H II region also known as the Tarantula Nebula. It is found in the Large Magellanic Cloud (LMC) and has a magnitude of 8.
LMC:
Geminga:
NGC 602:
M57 (Ring Nebula):
Kepler's SNR:
M42 (Orion Nebula):
Sagittarius A*:
M17:
M8:
M16 (Eagle Nebula):
M1 (Crab Nebula):
T Tauri:
SMC:

### Identification Tips

 This section requires cleanup to meet our quality standards. Please improve the page if possible.

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.

Also, in general, the brightest stars (lowest apparent magnitude) in a constellation are Alpha [constellation with slight variance], and second brightest Beta, and so on. After the Greek alphabet has been used up, numbers are used - 1 is dimmer than Omega but brighter than 2. However, there are exceptions - Betelgeuse (Alpha Orionis) usually appears dimmer than Rigel (Beta Orionis), and Castor (Alpha Geminorum) appears to be dimmer than Pollux (Beta Geminorum).

## Part II

 This section requires cleanup to meet our quality standards. Please improve the page if possible.

In Part II, students are asked to complete tasks relating to a set of particular topics. Teams must know about the general characteristics of stars, galaxies, star clusters, etc, and 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.

Teams are often asked to use information which includes the following:

• Hertzsprung-Russell diagrams
• Spectra
• Light curves
• Kepler's laws
• Radiation laws (Wien's and Stefan-Boltzmann)
• Period-luminosity relationship
• Stellar magnitudes and classification
• Parallax
• Redshift/blueshift
• Slides (PowerPoint)
• Photographs
• Star charts and animations

### Stellar Evolution

#### Pictures

Know these pictures, credited from Harvard's Chandrasekhar X-Ray Observatory and Hubble Space Telescope. Teams are frequently tasked with putting pictures like these in order based on the stellar life cycle.

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)

### Spectral Classification

#### 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.

Spectral Class Properties
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, and Algol

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

There are also S, N, and Y for brown dwarfs, which are generally not considered stars.

#### 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

There is also Type 0, for hypergiants. However, these are exceedingly rare; examples include VY Canis Majoris, the Pistol Star, and R136a1.

### Astrophysics Background

Recent changes to the rules have included more topics relating to basic astrophysics, including luminosity scales and relationships, temperature relationships, flux, and distance measures. A brief introduction to these topics is provided here. For a more in-depth study of astrophysics, please see the Astronomy page, but Reach for the Stars is unlikely to reach the level of complexity of the C Division event, so this would be mainly for enrichment purposes.

The radiation laws show relationships between stellar temperature, radius, and luminosity. Both Wien's Law and Stefan's Law are proportionality statements that can be turned into equations by introducing a proportionality constant.

At Division B it is unlikely that you will perform calculations with these laws. However, general questions regarding these laws, such as the proportionality, may still be asked.

Wien's Law: Wien's displacement law states that the wavelength where a blackbody emits most of its radiation is inversely proportional to the temperature. In equations,

$\lambda_{max}\propto\frac1T,\quad\lambda_{max}=\frac{b}{T}$,

where ${\lambda}_{max}$ is the maximum output of radiation from an object, $T$ is Temperature in Kelvin, and $b=2900\mu m\cdot K$ is known as Wien's displacement constant.

For example, the sun has surface temperature $T=5778K$, so its radiation peaks at $\lambda_{max}=\frac{2.9\cdot 10^{-3} m\cdot K}{5778K}=502nm$, a yellow-green color.

Stefan-Boltzmann's Law: The Stefan-Boltzmann Law states that the total energy emitted from a black-body per unit surface area is proportional to the fourth power of its temperature. In equations,
$j^*\propto T^4,\quad j^*=\sigma T^4,$

where $j^*$ is the total energy emitted per unit area, $T$ is Temperature in Kelvin, and $\sigma=5.67\cdot 10^{-8}\mathrm{W/m}^2\mathrm{K}^4$ is known as the Stefan–Boltzmann constant.

Since all blackbodies we encounter are spheres, it has surface area $A=4\pi R^2$, where $R$ is the radius of the object. Combining these equations, the total luminosity

$L=4\pi {R}^{2}\sigma {T}^{4}.$

For example, the sun has radius and temperature $R=6.96\cdot 10^8 m, T=5778K$. Plugging these into the equation, its luminosity is $3.85\cdot 10^{26}\mathrm{W}$, which is close to the experimental value of $3.83\cdot 10^{26}\mathrm{W}$.

Planck's Law: Planck's Law states that a hotter blackbody emits more energy at every frequency than a cooler blackbody. The equation form of the law is complicated, but on a radiance vs. temperature graph the curve for a hotter blackbody never dips below that of a cooler one.

### 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, galaxies are an important part of astronomy, so here is a brief background on the types of galaxies.

#### Spiral Galaxies

An example of a spiral galaxy: (M31 Andromeda Galaxy)
Spiral Galaxies are named so because they have prominent spiral arms and a central "galactic nucleus" or central bulge.
An example of a Barred-Spiral Galaxy: (NGC 1300)
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.

Spirals are classified by presence of a central bar and how tightly the rings are wound.

Sa tightly wound, no central bar moderately tightly wound, no central bar loosely wound, no central bar very loosely wound, no central bar tightly wound, central bar moderately tightly wound, central bar loosely wound, central bar very loosely wound, central 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. Also, they are classified by how spherical they are, with E followed by a number from zero to seven. Zero indicates perfectly spherical; seven indicates the extremely elongated and cigar-shaped.

An example of an Elliptical Galaxy:(M84)

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
An example of an Irregular Galaxy
Elliptical Galaxies that have been deformed by different forces- such as gravity. They contain a lot of interstellar matter. There are distinctions between "normal" irregular galaxies - with no hint of shape - and peculiar galaxies, that have some hint of form - usually, they were bent out of shape by outside forces or became violently active.

The Irregular Galaxies on the list for 2009 are:

-Large Magellanic Cloud (in Dorado and Mensa)

-Small Magellanic Cloud (in Tucana)

 This section requires cleanup to meet our quality standards. Please improve the page if possible.

Identification certainly is not the most important part of this event, it has sometimes been found to be easiest way to begin studying. 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.

Another tip is to use Quizlet (https://quizlet.com/), which is great for studying constellations, stars, and DSO's, and may show images you could see on a test.

## Sample Tests

Identification practice: Reach for the Stars Test (2009)
RFTS Test and Pic Sheet for the test
Also be sure to check out the Reach for the Stars Test Exchange.

## Useful Resources

Astronomy Today by Eric J. Chaisson