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Founded January 1970
Julian Date: 2458851.16
2019-2020:  LXXIX
              "Inside you is the potential to make yourself better...and
that is what it is to be human. To make yourself more than you are."
                            -Jean Luc Picard, Captain of the Starship
Enterprise


THE DAILY ASTRONOMER
Friday, January 3, 2020
Quiz XVII:  Alpha Centauri

[image: AlphaCentauriOrDie.jpg]

As the new year begins, we resume our quiz quest through the cosmos.     In
mid November we visited Pluto.  Now, we're jumping over the Trans Neptunian
Objects, Kuiper Belt and Oort Cloud in order to arrive at our next
destination:  Alpha Centauri, the closest star system to the Sun!



1.  About how far away is Alpha Centauri?
a.  1.4 light years
b.  2.7 light years
c.  4.4 light years
d. 5.9  light years

2. The Alpha Centauri system consists of how many stars?
a. 1
b. 2
c. 3
d. 6

3. Alpha Centauri is not visible from New England.  Where in the world
would an observer have to be located in order to see Alpha Centauri?
a. at the north pole
b. south of 29 degrees N latitude
c. south of the equator
d. within the Antartic Circle

4. How many confirmed planets have been detected in the Alpha Centauri
system?
a.  none
b.  1  - around Proxima Centauri
c.  1  - shared by Alpha Centauri A and B
d.  5

5. Where does Alpha Centauri rank on the list of the brightest stars in the
sky (excluding the Sun)?
a. 1st
b. 2nd
c. 3rd
d. 4th

6. What is the star's host constellation?
a. Crux
b. Vela
c. Centaurus
d. Pavo

7.  Proxima Centauri is the smallest member of the Alpha Centauri system.
Which of the following statements is/are true about this star?
a.  It is about 620 billion miles closer to the Sun than the other two
stars in the system
b.  Its mass is about 8% that of the Sun
c.  Not all scientists are convinced that Proxima is actually part of the
Alpha Centauri system
d.  It is the only star in the Alpha Centauri system -so far- that is known
to have a planet in orbit around it

8.  When will the Voyager I craft pass within 0.8 light years of Alpha
Centauri?
a.  45,000 years
b.  73,000 years
c.  110,111 years
d.  it won't.  It is moving in a different direction

9.  Alpha Centauri A is known as "Rigel Kentarus."   Alpha Centauri C is
known as "Proxima Centauri."  What is the proper name of Alpha Centauri B?
a. Bungula
b. Toliman
c. Lacaille 498
d. Alpha Centauri B doesn't have a proper name

10. How is the Alpha Centauri system moving relative to our solar system?
a.  it is moving closer to it
b.  it is moving farther away
c.  it is moving along a parallel trajectory, so its distance from the
solar system isn't changing
d. astronomers don't know.

ANSWERS

1.  c.  4.4 light years
A light year is the distance light travels in one year when moving through
a vacuum: about 5.8 trillion miles.    Even the closest star to the solar
system is so far away, light requires nearly four and a half years to
travel from Alpha Centauri to us.

2. c. 3
Alpha Centauri A, Alpha Centauri B and Proxima Centauri

3. b. south of 29 degrees N latitude
Yes, one can see Alpha Centauri from any location south of 29 degrees N,
including extreme southern parts of the United States.    However, it is
easier to find in the southern hemisphere, particularly within the
Antarctic Circle where it is circumpolar (never sets)

4.  b.  1  - around Proxima Centauri
Reports about planets around Alpha Centauri have been issued since 2015.
However, the existence of these planets has been disputed, except for one
planet known to be in orbit around the smallest star, Proxima Centauri.

5. c. 3rd
Sirius (Canis Major) is 1st
Canopus (Carina) is 2nd

6. c. Centaurus
The clue to answering this question is in the name, itself.  Alpha Centauri
is the brightest star in the constellation Centaurus.  The Bayer
Nomenclature System, developed by Johann Bayer, assigned Greek letters to
the stars within a given constellation in accordance with their respective
brightnesses. The brightest star in a constellation was denoted alpha, the
second beta, the third gamma, et cetera.    The star name combines its
Greek letter designation with the Latin genitive (possessive) of its host
constellation's name.  So, Alpha Centauri is the alpha star belonging to
Centaurus

7.  All statements are correct!

8   d.  it won't.  It is moving in a different direction
In about 40,000 years, it will come within 1.6 light years of Gliese 445 in
the constellation Camelopardalis.  It will come nowhere close to Alpha
Centauri.

9. b. Toliman
In 2018, the International Astronomical Union designated Alpha Centauri B
as Tolman, a name once applied to the star Alpha Centauri

10. a.  it is moving closer to it
The closest star system to the Sun is moving even closer at a rate of about
25 kilometers per second.  About 30,000 years from now, Alpha Centauri will
reach its minimum distance of about 3.7 light years.


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