< Radiation astronomy
NGC 6741 is the Phantom Streak Nebula. Credit: ESA/Hubble and NASA.

The first yellow source in Aquila is unknown.

This is a lesson in map reading, coordinate matching, and searching. It is also a project in the history of yellow astronomy looking for the first astronomical yellow source discovered in the constellation of Aquila.

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 yellow sources, you'll run into concepts and experimental tests that are an actual search.

First step

To succeed in finding a yellow source in Aquila is the first step.

Over the history of yellow 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. The coordinates are usually supplied by the yellow source observers.

Next, you'll need to determine the time stamp of its discovery and compare it with any that have already been discovered.

Control groups

Every experimental study has a control group. Here, a control group may be a yellow star already determined to be the first discovered in a specific part of the sky.

Astronomical sources

Def. a natural source usually of radiation in the sky especially at night is called an astronomical source.

A source of astronomical information on older detections of yellow sources may be included in the Science section of the lecture yellow astronomy.

Backgrounds

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.

Yellow rays are a form of radiation that is currently part of electromagnetic radiation intersecting the Earth. More information about radiation is in radiation astronomy, and specifically in yellow astronomy.

Traveling yellow sources

The Sun often appears yellow. Credit: NASA.

Many yellow sources do not remain in a constellation for lengthy periods. Some of these are the Sun and sources apparently in orbit around the Sun. The Sun travels through the 13 constellations along the ecliptic (the plane of the Earth's orbit around the Sun): the 12 of the Zodiac and the constellation Ophiuchus. These are described in source astronomy. Is Aquila one of the constellations of the Zodiac?

Constellations

This is an image of the International Astronomical Union (IAU) sky map of the constellation Aquila. Credit: IAU and Roger Sinnott & Rick Fienberg, Sky & Telescope magazine.
The former constellation Antinous was merged into Aquilla in 1930, but both can be seen in this 1825 chart from Urania's Mirror. Credit: Creator:Sidney Hall, Richard Rouse Bloxam (1765-1840), Adam Cuerden.

The Wikipedia article about the constellation Aquila contains a high school level description. The figure at right shows the sky map of Aquila. 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?

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

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

Aquila is a constellation catalogued by Ptolemy before 1800 b2k.

"In Greek mythology, Aquila is identified as the eagle that carried Zeus’ thunderbolts and was once dispatched by the god to carry Ganymede, the young Trojan boy Zeus desired, to Olympus to be the cup bearer of the gods."[1]

"In anothery story, the eagle is found guarding the arrow of Eros (represented by the constellation Sagitta), which hit Zeus and made him love-struck."[1]

"In yet another myth, Aquila represents Aphrodite disguised as an eagle, pretending to pursue Zeus in the form of a swan, so that Zeus’ love interest, the goddess Nemesis, would give him shelter. In the story, Zeus later placed the images of the eagle and the swan among the stars to commemorate the event."[1]

Star classification by color

Class Temperature[2]
K		 Conventional color Apparent color[3][4][5] Mass[2]
(solar masses, Mʘ)		 Radius[2]
(solar radii, Rʘ)		 Luminosity[2]
(bolometric, Lʘ)		 Hydrogen
lines		 Fraction of all
main sequence stars[6]
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%.

Testing a source

There are many web sites that may have a yellow source listed for the constellation Aquila.

Wikipedia sources

A. Constellation article

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

  1. [Right ascension] (RA): 19h 50m 46.99855s and
  2. [Declination] (Dec): +08° 52' 05.9563".

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

To evaluate the star as a yellow source, skip ahead to section "Yellow source".

B. Wikipedia search

Another way to look for yellow sources in the constellation is to perform a search on Wikipedia. Try "Aquila yellow" without the outside quotes. This yields about 361 returns which include Xi Aquilae b, 15 Aquilae, Nu Aquilae, HD 192699, Chi Aquilae, COROT-3, and Pi Aquilae.

To evaluate each of these as a yellow source, skip ahead to section "Yellow source".

SIMBAD sources

Another way to find possible yellow sources in Aquila is to use search queries on SIMBAD.

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

In the tan box, type in "region(19 50 46.99855 +08 52 05.9563, 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 Aquilae, 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: 10" 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 yellow astronomy for clues that may indicate whether a particular spectral type (Sp type) is a yellow source. If none of the objects listed seem to be described as a yellow source, try going "Back" and increasing the arcminutes from "10m" to "20m", and repeat until a yellow source is found.

Once you believe you have discovered a yellow source, proceed to the section "Yellow source".

Yellow sources

There are several ways to evaluate a yellow source for the constellation Aquila.

Wikipedia source

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 "yellow", or "yellow rays". Does the article mention whether or not the source is a yellow 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 yellow source in Aquila edit the "Non-yellow source in Aquila" section near the bottom of the page with an entry similar to "# Alpha Aquilae 12 January 2012 at 06:47 Wikipedia article "Alpha Aquilae".", 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 yellow source in Aquila edit the section below "Yellow source in Aquila" with a similar entry.

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

SIMBAD source

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, "19 50 46.99855 +08 52 05.9563".

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 yellow source?

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

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

SIMBAD time stamp

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 yellow source, edit the "Non-yellow source in Aquila" 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 yellow source in Aquila (did you check the coordinates vs. the map of Aquila?), make an entry something like the ones in the section "Yellow source in Aquila".

Challenging an entry

Any entry in either the section "Yellow source in Aquila" or "Non-yellow source in Aquila" can be challenged. The time stamp can be challenged to see if there is an earlier one. The source can be challenged by an earlier source.

Wikipedia challenge

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 yellow source?

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

SIMBAD challenge

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 yellow source within the constellation on SIMBAD, the next step is to find the earliest time stamp of discovery.

Primary sources

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

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 "yellow" to see if the source has a reference indicating it is a yellow source. And, look for the earliest one. Compose an entry using the primary source.

SIMBAD test source

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 "Yellow source in Aquila". 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

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

If you have found an earlier time stamp for the source than the one listed in the section below "Non-yellow source in Aquila" 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 "Yellow source in Aquila", edit the section with your result. Or, if you found another yellow source with a comparable or earlier time stamp, edit the section with your result.

Yellow sources in Aquila

  1. Eta Aquilae 20 August 2011 at 06:54 Wikipedia article "Eta Aquilae". "It is a yellow-white supergiant, and is about 3000 times more luminous than the Sun, with a diameter about 60 times that of the Sun." "It is a Cepheid variable star, with its apparent visual magnitude varying between 3.5 and 4.4 with a period of 7.176641 days. Eta Aquilae is one of the easiest Cepheids to distinguish by the naked eye."[1] Marshallsumter 20:12, 25 January 2012 (UTC)
  2. Beta Aquilae 21 March 2012 at 16:35 Wikipedia article "Beta Aquilae", does not include the word "yellow" in the text but by the star classification above and spectral type G8 IVvar in the Starbox it is a yellow star. Marshallsumter (talk) 00:16, 27 March 2012 (UTC)
  3. Alshain (Beta Aquilae) SIMBAD has spectral type as G9.5IV, followed by a reference[7]. The earliest time stamp is March 28, 2006. Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified.[8] Marshallsumter (talk) 00:36, 27 March 2012 (UTC). But, "The Atlas of Stellar Spectra was published fifty years ago by W.W. Morgan, P.C. Keenan, and E. Kellman(1943). Since then, there have been supplementary lists of standard stars and atlases published by Morgan and/or Keenan in 1953, 1973, 1976, and 1978. In these later publications, some of the types for the standard stars were modified in the light of better data."[8] In 1953, β Aql is listed as the standard star for G8 IV.[9] A G8 IV is a yellow (or orange-yellow) star. --Marshallsumter (talk) 23:41, 13 August 2012 (UTC)

Non-yellow sources in Aquila

  1. Alpha Aquilae 12 January 2012 at 06:47 Wikipedia article "Alpha Aquilae". Marshallsumter 20:12, 25 January 2012 (UTC).
  2. Beta Aquilae "The variable and comparison stars are, in the Harvard system, ... . H.R. 7602, β Aquilae, magnitude 3.90, spectrum K. The Mt. Wilson spectral types are ... β Aquilae, G7."[10] "[T]oward the end of the series [of observations] β Aquilae was fainter than at the beginning."[10] Class K are orangish stars that are slightly cooler than our Sun. Apparently, in 1922, β Aquilae was an orangish star. --Marshallsumter (talk) 23:24, 13 August 2012 (UTC). In 1908, β Aql is listed as a spectral class K II with a suspected period of variability of two months.[11] --Marshallsumter (talk) 03:44, 14 August 2012 (UTC). "It is well known that [β Aquilae] has sensibly diminished in brightness within memory of persons living; but no change has taken place in this respect for many years past, nor is there any reason to suppose that it was ever brighter than γ [Aquilae]. ... Flamsteed rated β Aquilae as 3 1/2; whilst Hevelius, remarkably enough, estimated it as only (what it is now) the fourth, although later observers reckoned it, like Flamsteed, of the 3 1/2 magnitude."[12] --Marshallsumter (talk) 04:11, 14 August 2012 (UTC).

Oldest records

  1. Beta Aquilae: Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified.[8]

SIMBAD annotations

For any particular source, the SIMBAD record may indicate that it is not a yellow source yet above you may have found at least two refereed journal articles to indicate that it is. Use the second SIMBAD External links to directly display the SIMBAD database in France.

Enter the name source you have found into the search box. Scroll down to the Annotations :. Look for the link "add an annotation to this object". With browser open to the literature citations available, click on this link. You may need to register as a user. It's free. Post your annotation containing the literature references.

Hypotheses

  1. The first yellow source in Aquila may have been discovered around 42,000 b2k.

See also

References

  1. 1 2 3 4 Constellation-Guide (18 July 2014). Aquila Constellation. Constellation-Guide. Retrieved 2014-07-18.
  2. 1 2 3 4 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.
  3. ↑ The Guinness book of astronomy facts & feats, Patrick Moore, 1992, 0-900424-76-1
  4. ↑ 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.
  5. ↑ What color are the stars?, Mitchell Charity. Accessed online March 19, 2008.
  6. ↑ 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.
  7. ↑ Gray, R. O.; Corbally, C. J.; Garrison, R. F.; McFadden, M. T.; Bubar, E. J.; McGahee, C. E.; O'Donoghue, A. A.; Knox, E. R. (July 2006). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc-The Southern Sample". The Astronomical Journal 132 (1): 161-70. doi:10.1086/504637.
  8. 1 2 3 R. F. Garrison (December 1993). "Anchor Points for the MK System of Spectral Classification". Bulletin of the American Astronomical Society 25: 1319. http://www.astro.utoronto.ca/~garrison/mkstds.html. Retrieved 2012-02-04.
  9. ↑ H. L. Johnson and W. W. Morgan (May 1953). "Fundamental stellar photometry for standards of spectral type on the revised system of the Yerkes spectral atlas". The Astrophysical Journal 117 (3): 313-52.
  10. 1 2 Charles Clayton Wylie (November 1922). "The Cepheid Variable η Aquilae". The Astrophysical Journal 56 (4): 217-31. http://books.google.com/books?hl=en&lr=&id=Qk1JAAAAYAAJ&oi=fnd&pg=PA215&ots=Rfe1lgYqEb&sig=yV__nyTknvrG_-NnyEvEBzqMKSg#v=onepage&f=false. Retrieved 2012-08-13.
  11. ↑ H. E. Lau (January 1914). "Über die Potsdamer Beobachtungen des » Schleiers « im Jahre 1908". Astronomische Nachrichten 196 (1): 425-30.
  12. ↑ W. T. Lynn (August 1885). "Brightness of β Aquilae -- A Correction.". The Observatory 8 (8): 271.

Further reading

{{Principles of radiation astronomy}}{{Radiation astronomy resources}}

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