Radiation astronomy/First blue source in Boötes

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This is a visual image of lambda Boötis. Credit: Aladin at SIMBAD.

The first blue source in Boötes is unknown.

This is a lesson in map reading, coordinate matching, and searching.

It is also a project in the history of blue astronomy looking for the first astronomical blue source discovered in the constellation of Boötes.

Nearly all the background you need to participate and learn by doing you've probably already been introduced to at a secondary level.

Some of the material and information is at the college or university level, and as you progress in finding blue sources, you'll run into concepts and experimental tests that are an actual search.

To succeed in finding a blue source in Boötes is the first step. Next, you'll need to determine the time stamp of its discovery and compare it with any that have already been found. Over the history of blue astronomy a number of sources have been found, many as point sources in the night sky. These points are located on the celestial sphere using coordinate systems. Familiarity with these coordinate systems is not a prerequisite. Here the challenge is geometrical, astrophysical, and historical.

Control groups[edit]

Main source: Control groups

A control group for this experiment may be a blue source observed by ancient hominins in their version of the constellation Boötes.

Astronomical blue sources[edit]

This image shows the blue glow generated by the synchrotron radiation from the elliptical galaxy M87's energetic jet. Credit: Hubble Space Telescope.

The image at right shows the blue light, towards the lower right, due to synchrotron radiation, of a jet emerging from the bright active galactic nucleus (AGN) core of Messier 87.

First sources[edit]

The "earliest known astronomy anywhere in the world [is] that of the Australian Aborigines, whose culture has existed for some 40,000 years".[1]

"The Aranda tribes of Central Australia, for example, distinguish red stars from white, blue and yellow stars."[1]

Backgrounds[edit]

To introduce yourself to some aspects of the challenge may I suggest reading the highlighted links mentioned above, and if you're curious, those listed under the section "See also" below.

Blue rays are a form of radiation that is currently part of the electromagnetic radiation intersecting the Earth. More information about the radiation of astronomy is in radiation astronomy and blue astronomy.

Constellations[edit]

This is an image of the International Astronomical Union (IAU) sky map of the constellation Boötes. Credit: IAU and Roger Sinnott & Rick Fienberg, Sky & Telescope magazine.
This card shows Boötes, Canes Venatici, Coma Berenices, and Quadrans Muralis. Credit: Sidney Hall, Adam Cuerden restorationist.

The Wikipedia article about the constellation Boötes contains a high school level description. The figure at right shows the sky map of Boötes. Around the edges of the map are coordinates related to longitude and latitude, but with the Earth rotating on its axis every 24 hours the celestial coordinates must remain fixed. How has this been accomplished?

"Boötes was one of the 48 constellations described by the 2nd century astronomer Ptolemy and is now one of the 88 modern constellations."[2]

"In ancient Babylon the stars of Boötes were known as SHU.PA. They were apparently depicted as the god Enlil, who was the leader of the Babylonian pantheon and special patron of farmers.[3]"[2]

The second image at the right is "Boötes as depicted in Urania's Mirror, a set of constellation cards published in London c.1825. In his left hand he holds his hunting dogs, Canes Venatici. Below them is the constellation Coma Berenices. Above the head of Boötes is Quadrans Muralis, now obsolete, but which lives on as the name of the early January Quadrantid meteor shower. Mons Mænalus can be seen at his feet."[2]

Also, in the Wikipedia article is a list of stars in Boötes.

From the Wikipedia article on the Zodiac, is Boötes a zodiacal constellation?

Earlier versions of the stars that now compose Boötes may occur in astrohistory as they are found or rediscovered.

Star classification by color[edit]

Class Temperature[4]
K
Conventional color Apparent color[5][6][7] Mass[4]
(solar masses, Mʘ)
Radius[4]
(solar radii, Rʘ)
Luminosity[4]
(bolometric, Lʘ)
Hydrogen
lines
Fraction of all
main sequence stars[8]
O ≥ 33,000 K blue blue ≥ 16 ≥ 6.6 ≥ 30,000 Weak ~0.00003%
B 10,000–33,000 K blue to blue white blue white 2.1–16 1.8–6.6 25–30,000 Medium 0.13%
A 7,500–10,000 K white white to blue white 1.4–2.1 1.4–1.8 5–25 Strong 0.6%
F 6,000–7,500 K yellowish white white 1.04–1.4 1.15–1.4 1.5–5 Medium 3%
G 5,200–6,000 K yellow yellowish white 0.8–1.04 0.96–1.15 0.6–1.5 Weak 7.6%
K 3,700–5,200 K orange yellow orange 0.45–0.8 0.7–0.96 0.08–0.6 Very weak 12.1%
M ≤ 3,700 K red orange red ≤ 0.45 ≤ 0.7 ≤ 0.08 Very weak 76.45%.[9]

Testing a source[edit]

There are many web sites that may have a blue source listed for the constellation Boötes.

Wikipedia sources[edit]

A. Constellation article

Under "Notable features" in the Wikipedia article on the constellation Boötes is the list of stars in Boötes. Click on this link. In the table of this Wikipedia article is α Boo. To the right are coordinates:

  1. [Right ascension] (RA): 14h 15m 40.35s and
  2. [Declination] (Dec): +19° 11' 14.2".

Find these coordinates on the Boötes map at the right. Is alpha Boötis really inside the boundaries of the constellation?

To evaluate the star as a blue source, skip ahead to the section "Blue source".

B. Wikipedia search

Another way to look for blue sources in the constellation is to perform a search on Wikipedia. Try "Boötes blue" without the quotes. This yields 2,236 possible astronomical blue source candidates.

To evaluate a blue source, skip ahead to section "Blue source".

SIMBAD sources[edit]

Another way to find possible blue sources in Boötes is to use search queries on SIMBAD.

Click on the SIMBAD link under "External links" below, then click on "Criteria query" or "by criteria".

In the tan box, type in "region(05 45 08.9173 -16 42 58.017, 10m)", without the quotes. This tells the SIMBAD computer you are interested in a circular region of the celestial sphere centered on the coordinates for alpha Boötis, with a radius of 10 arcminutes (m).

Notice on the page over at the right from the tan colored box: "Return". The default is "object count". Click on "submit query". In a few moments a result something like "Number of objects: 9" should appear. Click "Back" to see the tan box again.

To see if you have found at least one object, change "Return" to "display" by clicking on the circle to its left, then "submit query".

SIMBAD should display a list of objects. Read through the resource blue astronomy for clues that may indicate whether a particular spectral type (Sp type) is a blue source. If none of the objects listed seems to be described as a blue source, try going "Back" and increasing the arcminutes from "10m" to "20m", and repeat until a blue source is found.

Once you believe you have discovered a blue source, proceed to the section "Blue source".

A blue source[edit]

There are several ways to evaluate a blue source for the constellation Boötes.

Stellar classifications[edit]

Stellar classification places the range of effective surface temperatures for conventional color blue, bluish, or blue white stars as the class K stars as class O ≥33,000 K blue, 10,000-33,000 K blue to blue white, and 7,500-10,000 K to white, or white to blue white (apparent color).

Typical characteristics
Stellar
Class
Standard
star
* Not a standard star.
Radius
(Rʘ)
Luminosity
(Lʘ)
Teff
(K)
Linear
approximation
Planckian radiator
peak wavelength
(nm)
B9 HR 5475 320% 21400% 12,417 --- 241
A0 Lambda Boötis 170% 1910% 8,720 --- 344
A1V 1 Boötis --- 5600% 9,863 --- 304
A8IV κ2 Boötis --- 2800% 7,760 --- 387

Some of the effective temperatures for the standard stars are fairly recent.[10]

The Planckian radiator peak wavelength for any effective surface temperature in K may be found using your handheld calculator with the formula:

y=(1.48833/(0.0000495*6060))*exp(1.48833/(0.0000495*6060))/(exp(1.48833/(0.0000495*6060))-1)-5.

Depending on the internal software, ask it to print or display y. Iteratively enter different temperatures (e.g. 6060 in the equation) and wavelengths (e.g. 495 nm as 0.0000495 in the equation) to see how close to zero you are.

For the temperature, wavelength pair (6060 K,495 nm), the value is -3.419065E-03. This is close in the third digit.

The temperature, wavelength pair (3800 K,690 nm) gives an equation of

y=(1.48833/(0.0000690*3800))*exp(1.48833/(0.0000690*3800))/(exp(1.48833/(0.0000690*3800))-1)-5, with a value of 0.695831, which is not as close, and suggests an error in the first digit.

When the temperature is higher than the minimum for a specific wavelength, the value of the equation is negative. When the wavelength is shorter than the minimum for a specific temperature, the value of the equation is positive.

Wikipedia source[edit]

Click on the link to the Wikipedia article. After you've enjoyed reading about the source, use the 'find' command of your browser to see if this Wikipedia page mentions anything about "blue" or "blue rays". Does the article mention whether or not the source is a blue source?

What is the current time stamp for the Wikipedia article on the source? [Hint]: look for something like "This page was last modified on 12 January 2012 at 06:47." very near the bottom of the page. For now this is an adequate time stamp.

From reading the Wikipedia article on the source, if you believe the text demonstrates that the source is not a blue source in Boötes edit the "Non-blue source in Boötes" section near the bottom of the page with an entry similar to "# Alpha Boötis 12 January 2012 at 06:47 Wikipedia article "Alpha Boötis".", without the outer quotes, and finish the entry with four "~"s without the quotes after the period. The date included with your designation or username is a time stamp for the entry. The last portion of the entry is the source of your information.

On the other hand, if there are one or more sentences in the article that you believe demonstrates that the source is a blue source in Boötes edit the section below "Blue source in Boötes" with a similar entry.

Go to the section entitle, "Challenging an entry".

SIMBAD source[edit]

To check any source (even one from Wikipedia) on SIMBAD, click of the "External link" to the "SIMBAD Astronomical Database".

At the lower right side of the SIMBAD Astronomical Database page is a "Basic search" box. There are several ways to try your target:

  1. source name: without the quotes or
  2. source coordinates: without the quotes, for example, "05 45 08.9173 -16 42 58.017".

If you are looking at a SIMBAD generated table which lists possible targets, click on one.

On its SIMBAD page move over to the right side until you see an Aladin visual photograph of the object. Is it a blue source?

Even if the source does not look blue, look down the left hand side of the page for "Spectral type:". From your reading of blue astronomy, do you believe the source is a blue source, or not? Noting that SIMBAD does, or does not consider the source to be a blue source is important, so skip down to the "SIMBAD time stamp" section.

If you have already found a blue source (or a table of them) using SIMBAD, click on the blue link identifier for the first.

SIMBAD time stamp[edit]

Peruse the SIMBAD page for a time stamp or date of last revision. [Hint: it may look something like "2012.01.09CET20:10:02" and be in the upper right.]

If the entry at SIMBAD convinces you that the source is not a blue source, edit the "Non-blue source in Boötes" section near the bottom of this page and type in an entry similar to "# Source Name 2012.01.09CET20:10:02 SIMBAD article "SIMBAD source name".", without the first set of quotes, followed by four ~s.

If your SIMBAD analysis convinces you that you have found a blue source in Boötes (did you check the coordinates vs. the map of Boötes?), make an entry something like the ones in the section "Blue source in Boötes".

Challenging an entry[edit]

Any entry in either the section "Blue source in Boötes" or "Non-blue source in Boötes" can be challenged. The time stamp may be challenged to see if there is an earlier one. The source may be challenged by an earlier source.

Wikipedia challenge[edit]

Is Wikipedia a 'primary source', or does the Wikipedia article cite a source?

Even though Wikipedia has an article on the source, is it a good place to stop in testing whether the source has been detected as an astronomical blue source?

If the Wikipedia article cites a primary source, skip down to the section on "Primary sources".

SIMBAD challenge[edit]

Is SIMBAD a 'primary source'?

SIMBAD is an astronomical database provided by the Centre de Données astronomiques de Strasbourg. It is an authoritative source, but they do occasionally make a mistake.

If you find a blue source within the constellation on SIMBAD, the next step is to find the earliest time stamp of discovery.

Primary sources[edit]

Primary sources may be searched for possible additional information perhaps not yet evaluated by SIMBAD or not presented in a Wikipedia article about a source.

Wikipedia test source[edit]

For a Wikipedia article that cites a primary source, scroll down to the reference and open the reference. Read through the article looking for where the source mentioned in the Wikipedia article occurs. Some primary source authors may use source designations that are not mentioned in the Wikipedia article. To look for other designations, click on the link to SIMBAD in the "External links" on this page, enter the source name from the Wikipedia article, and see if other names are mentioned in the article.

When none of the names are mentioned, click on the link for "Google Advanced Search" in the list of "External links", enter the source name or designation(s) such as "Gliese 866", with "blue" to see if the source has a reference indicating it is a blue source. And, look for the earliest one. Compose an entry using the primary source.

SIMBAD test source[edit]

Further down the SIMBAD page is a list of "Identifiers". Click on the blue bold portion.

On the page that appears, there should be a primary source listed after Ref:. Click on the blue link with the oldest year. This yields an earlier time stamp and entry citation like the current one in the section "Blue source in Boötes". If you find another source or an earlier time stamp, compose a similar entry and edit the section. Additional information to add into the reference can be found by clicking on "ADS services" from the SIMBAD page.

Changing an entry[edit]

From your analysis of the source so far, is it a blue source?

If you have found an earlier time stamp for the source than the one listed in the section below "Non-blue source in Boötes" and the answer to the above question is "no", you can edit the section with your result. Or, you can leave the entries as is and try another star or object.

If you have found an earlier time stamp for the source than the one listed in the section below "Blue source in Boötes", edit the section with your result. Or, if you found another blue source with a comparable or earlier time stamp, edit the section with your result.

Blue sources in Boötes[edit]

  1. "NGC 5548 is a Type I Seyfert galaxy with a bright blue/white core. It is ... in the constellation Boötes. ... This galaxy was studied by the Multicolor Active Galactic Nuclei Monitoring 2m telescope.[11] ... This page was last modified on 12 June 2012 at 15:52."[12] --Marshallsumter (talk) 02:31, 17 August 2012 (UTC)
  2. Pi Boötis, specifically HR 5475, "[t]he brighter component is a blue-white B-type main sequence dwarf ... This page was last modified on 14 July 2012 at 05:38."[13] --Marshallsumter (talk) 02:56, 17 August 2012 (UTC)

Non-blue sources in Boötes[edit]

  1. Arcturus, or alpha Boötis, is an "orange-yellow ... [s]pectral type K1.5IIIFe-0.5 ... [or] K1.5 IIIpe orange giant star ... This page was last modified on 16 August 2012 at 03:58."[14] --Marshallsumter (talk) 01:42, 17 August 2012 (UTC)

Hypotheses[edit]

Main source: Hypotheses
  1. The first blue source in Boötes was likely observed over 42,000 b2k.

See also[edit]

References[edit]

  1. 1.0 1.1 R Haynes (June 27, 1996). Raymond Haynes, Roslynn Haynes, David Malin & Richard McGee. ed. Explorers of the southern sky: a history of Australian astronomy. The Pitt Building, Trumpington Stree, Cambridge CB2 1RP, England UK: Cambridge University Press. pp. 527. ISBN 0521365759. http://books.google.com/books?id=XoeiJxMmXZ8C&lr=&source=gbs_navlinks_s. Retrieved 2013-08-02. 
  2. 2.0 2.1 2.2 Lua error in Module:Citation/CS1 at line 3505: bad argument #1 to 'pairs' (table expected, got nil).
  3. White 2008, p. 207.
  4. 4.0 4.1 4.2 4.3 Tables VII, VIII, Empirical bolometric corrections for the main-sequence, G. M. H. J. Habets and J. R. W. Heinze, Astronomy and Astrophysics Supplement Series 46 (November 1981), pp. 193–237, bibcode=1981A&AS...46..193H. Luminosities are derived from Mbol figures, using Mbol(ʘ)=4.75.
  5. The Guinness book of astronomy facts & feats, Patrick Moore, 1992, 0-900424-76-1
  6. "The Colour of Stars". Australia Telescope Outreach and Education. 2004-12-21. Retrieved 2007-09-26.  — Explains the reason for the difference in color perception.
  7. What color are the stars?, Mitchell Charity. Accessed online March 19, 2008.
  8. Glenn LeDrew (February 2001). "The Real Starry Sky". Journal of the Royal Astronomical Society of Canada 95 (1 (whole No. 686, February 2001), pp. 32–33. Note: Table 2 has an error and so this article will use 824 as the assumed correct total of main-sequence stars). http://adsabs.harvard.edu/abs/2001JRASC..95...32L. 
  9. Lua error in Module:Citation/CS1 at line 3505: bad argument #1 to 'pairs' (table expected, got nil).
  10. S. Catalano, K. Biazzo, A. Frasca and E. Marilli (November 2002). "Measuring starspot temperature from line depth ratios". Astronomy & Astrophysics 394 (3): 1009-21. doi:10.1051/0004-6361:20021223. http://www.aanda.org/articles/aa/full/2002/42/aa2543/node1.html. Retrieved 2012-08-15. 
  11. Masahiro Suganuma, Yuzuru Yoshii, Yukiyasu Kobayashi, Takeo Minezaki, Keigo Enya, Hiroyuki Tomita, Tsutomu Aoki, Shintaro Koshida, and Bruce A. Peterson (March 1, 2006). "Reverberation Measurements of the Inner Radius of the Dust Torus in Nearby Seyfert 1 Galaxies". The Astrophysical Journal 639 (1): 46-63. doi:10.1086/499326. http://iopscience.iop.org/0004-637X/639/1/46/fulltext. Retrieved 2012-08-16. 
  12. Lua error in Module:Citation/CS1 at line 3505: bad argument #1 to 'pairs' (table expected, got nil).
  13. Lua error in Module:Citation/CS1 at line 3505: bad argument #1 to 'pairs' (table expected, got nil).
  14. Lua error in Module:Citation/CS1 at line 3505: bad argument #1 to 'pairs' (table expected, got nil).

External links[edit]

{{Astronomy resources}}{{Principles of radiation astronomy}}{{Reasoning}}