< Radiation astronomy
This is an image of the Sun using an H I violet band pass filter. Credit: NASA.

The first violet source in Leo is unknown.

The field of violet astronomy is the result of observations and theories about violet sources detected in the sky above.

The first astronomical violet source discovered may have been the Sun.

But, violet waves from the Sun are intermingled with other radiation so that the Sun may appear as other than a primary source for violet waves.

The early use of sounding rockets and balloons to carry violet detectors high enough may have detected violet waves from the Sun as early as the 1940s.

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

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

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

First step

The first step is to succeed in finding a violet source in Leo.

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

Over the history of violet 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 violet source observers.

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 violet sources is included in the Science section of the lecture/article violet 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.

Violet waves are a form of radiation that is currently part of electromagnetic radiation intersecting the Earth. More information about radiation is in radiation astronomy.

Traveling violet sources

This picture was taken in the ultraviolet (extremely blue) light. Credit: EIT, SOHO, ESA, and NASA.

Many violet 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. Leo is one of the constellations of the Zodiac.

Constellations

This is an image of the International Astronomical Union (IAU) sky map of the constellation Leo. Credit: IAU and Sky & Telescope magazine (Roger Sinnott & Rick Fienberg).
The image shows the constellation Leo as it can be seen by the naked eye (the bright object in the centre of the picture is the planet Jupiter). Credit: AlltheSky.com.
Leo, with Leo Minor above, is depicted in Urania's Mirror, a set of constellation cards published in London c.1825. Credit: Sidney Hall, Richard Rouse Bloxam, Adam Cuerden.

The Wikipedia article about the constellation Leo contains a high school level description. The figure at top right shows the sky map of Leo. 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 relative to the background light sources in the sky.

Leo is one of the constellations of the zodiac, lying between Cancer to the west and Virgo to the east. Its name is Latin for lion, and to the ancient Greeks represented the Nemean Lion killed by the mythical Greek hero Heracles (known to the ancient Romans as Hercules) as one of his twelve labors.

Leo is one of the 48 constellations listed by the 2nd-century astronomer Ptolemy. The lion's mane and shoulders also form an asterism known as "the Sickle," which to modern observers may resemble a backwards "question mark."[1]

Leo was one of the earliest recognized constellations, with archaeological evidence that the Mesopotamians had a similar constellation as early as 4000 BCE.[2] The Persians called Leo Ser or Shir; the Turks, Artan; the Syrians, Aryo; the Jews, Arye; the Indians, Simha, all meaning "lion".

Some mythologists believe that in Sumeria, Leo represented the monster Khumbaba, who was killed by Gilgamesh.[3]

In Babylonian astronomy, the constellation was called UR.GU.LA, the "Great Lion"; the bright star Regulus was known as "the star that stands at the Lion's breast." Regulus also had distinctly regal associations, as it was known as the King Star.[4] The figure is reminiscent of modern depictions of Leo.

In Greek mythology, Leo was identified as the Nemean Lion which was killed by Heracles (Hercules to the Romans) during the first of his twelve labours.[2][5] The Nemean Lion would take women as hostages to its lair in a cave, luring warriors from nearby towns to save the damsel in distress, to their misfortune.[6] The Lion was impervious to any weaponry; thus, the warriors' clubs, swords, and spears were rendered useless against it. Realizing that he must defeat the Lion with his bare hands, Hercules slipped into the Lion's cave and engaged it at close quarters.[6] When the Lion pounced, Hercules caught it in midair, one hand grasping the Lion's forelegs and the other its hind legs, and bent it backwards, breaking its back and freeing the trapped maidens.[6] Zeus commemorated this labor by placing the Lion in the sky.[6]

The Roman poet Ovid called it Herculeus Leo and Violentus Leo. Bacchi Sidus (star of Bacchus) was another of its titles, the god Bacchus always being identified with this animal. However, Manilius called it Jovis et Junonis Sidus (Star of Jupiter and Juno).

Early Hindu astronomers knew it as Asleha and as Sinha, the Tamil Simham.

As of 2002, Sun appears in the constellation Leo from 18 December to 18 January.

The shape, size, and to some extent its location as a constellation has changed over time. The second figure at right is an earlier version.

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

Searching catalogs

In the lecture/article violet astronomy in its science section is a list of older catalogs of violet sources. Using the constellation description in the previous section and the range of coordinates for the constellation in source astronomy, scan through the coordinates for these violet sources to see if any may be within Leo.

If you find any that are, skip down to the section violet sources in Leo and make an entry. Be sure to check the coordinate era, most B1950 coordinates have changed slightly to the new J2000 set. Try the catalog designation at either SIMBAD website.

Testing a source

There are many web sites that may have an violet source listed for the constellation Leo. Some that you may wish to try are in the External links section near the bottom of this lesson.

Wikipedia sources

A. Constellation article

Under "Notable features" in the Wikipedia article on the constellation Leo is the list of stars in Leo. Click on this link. In the table of this Wikipedia article are Denebola (β Leo) and Regulus (α Leo). To the right are coordinates:

Right ascension (RA): 10h 08m 22.46s and Declination (Dec): +11° 58' 01.9".

Find these coordinates on the Leo map at the right.

To evaluate the star as a violet source, skip ahead to section "Violet sources".

B. Wikipedia search

Another way to look for violet sources in the constellation is to perform a search on Wikipedia. Try "violet Leo" without the quotes. This yields some 287 returns.

Scroll down the list looking for some clear text stating that an violet source in Leo is discussed.

When you find one, skip ahead to the section "Violet sources".

SIMBAD sources

Another way to find possible violet sources in Leo is to use search queries on SIMBAD.

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

In the tan box, type in "region(10 08 22.311 +11 58 01.95,10m)", 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 Leonis, or Regulus, with a radius of 10 arcminutes (10m), or try 10d for 10 degrees.

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: 14" should appear. Click "Back" to see the tan box again.

Adding an object type such as & otype='UV' to the region request reduces the returned number to those that are violet sources, one within 10 m of alpha Leonis, specifically Regulus. Using 10d instead with & otype='UV' yields 563 violet sources. But, all of the otypes listed at Object classification in SIMBAD may contain violet stars, yet may not state that any are violet sources.

Using only otype='UV' yields 91216 UV sources in SIMBAD.

The SIMBAD criteria search allows you to specify spectral types for possible stars. The criteria "sptype" (the exact spectral type): returns only the objects having the requested spectral type (i.e. sptype = 'k0' does not return 'K0III',...). And, "sptypes" should be used to retrive all objects having a spectral type containing the one specified; i.e., sptypes = 'K0' will return all objects having 'K0' as a spectral type, but also 'K0III' or 'K0IIIp', ...). This may also be comgined using an "&" to pick sources you might like.

Here again no information about possible violet sources may be listed. You have to click on one of objects in the list.

If a flare star is a likely source of violet waves, which it may because flares also generate violet rays, then entering otype='Fl*' should locate likely violet sources.

Using only otype='Fl*' on SIMBAD yields 2582 in all of SIMBAD.

Using otype='UV' & otype='Fl*' yields 105 in all of SIMBAD.

SAO/NASA Astrophysics Data System

In the naming of sources per constellation, the genitive is in common use. For Leo, the genitive is Leonis.

Click on the SAO/NASA Astrophysics Data System link below in the "External links". Try "Leo violet" without the quotes, "Regulus violet", or "alpha leonis" with quotes, followed by violet. The first returns 530 primary source articles that may contain violet sources in Leo. The second returns five.

Click on a link below # Bibcode Authors. If the Abstract describes the detection of violet waves from a source in the constellation Leo, go to the next section under "SAO/NASA Astrophysics Data System".

If it does not, try another bibcode link.

Violet sources

There are several ways to evaluate a violet source for the constellation Leo.

Wikipedia sources

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 violet waves. Does the article mention whether or not the source is a violet 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 25 December 2013 at 20:12." 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 violet source in Leo edit the "Non-violet sources in Leo" section near the bottom of the page with an entry similar to "# Alpha Leonis 25 December 2013 at 20:12 Wikipedia article "Alpha Leonis", without the 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 violet source in Leo edit the section below "violet sources in Leo" with a similar entry.

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

From the lecture/article on violet astronomy, the violet radiation band may not have an appropriate wavelength temperature pair.

Is the primary star of alpha Leonis a violet star, or a violet source?

Wikimedia commons

Another possible website for violet sources is Wikimedia Commons. Try entering "violet Leo" without the quotes.

This returns the one image at the top of the page, plus four others that may not be violet images. None are astronomy images.

SIMBAD sources

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 23 53.17483 −40 36 57.3705".

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

Having SIMBAD list all of its 2582 flare stars produces an apparently formidable task. Try searching with your browser using "Leo".

Many of the flare stars listed do not include a constellation designation. Letting SIMBAD plot all of these flare stars and comparing the plot with the constellation sky chart may help.

There are over 91,000 otype='UV' listed in SIMBAD. Plotting them may be helpful or scanning them using -40, per the example, with your browser may eventually reveal at least one violet source.

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

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 violet source, edit the "Non-violet sources in Leo" 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 may have found a violet source in Leo (did you check the coordinates vs. the map of Leo?), make an entry something like the ones in the section "Violet sources in Leo".

SAO/NASA Astrophysics Data System sources

If the abstract states that a violet source in Leo is detected or studied, consider entering it in the section "Violet sources in Leo" below.

Abstract time stamp

On the abstract page is a Publication Date:. This may serve as a time stamp for establishing that the source is detected as a violet source on or before the date of publication. The time stamp followed by four ~s for your verification as determiner in the section "violet sources in Leo" completes your entry.

Challenging an entry

Any entry in either the section "violet sources in Leo" or "Non-violet sources in Leo" 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 challenges

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 violet source?

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

SIMBAD challenges

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

SAO/NASA Astrophysics Data System challenge

Is the SAO/NASA Astrophysics Data System abstract entry a primary source?

The SAO/NASA Astrophysics Data System is an astronomical database provided by the High Energy Astrophysics Division at the Harvard-Smithsonian Center for Astrophysics of Harvard University. The abstract has been copied from the actual article in a scientific journal or other publication. Mistakes can be made and the article may record within its text exact dates when the observation or detection of millimeter waves actually occurred. Such a record may provide an earlier time stamp.

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 sources

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

SIMBAD test sources

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

On the page that appears 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 "violet sources in Leo". 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.

SAO/NASA Astrophysics Data System sources test

Click on either the "Electronic Refereed Journal Article (HTML)" or "Full Refereed Journal Article (PDF/Postscript)", if available.

Depending on the article display, if the abstract is repeated and the article is listed as FREE, click on either the PDF or HTML version.

While scanning or reading the article look for "Observations" (or use the Find function of your browser) and the possible inclusion of dates for these. If more than one violet source in Leo are detected, which one(s) would you list in the section "violet sources in Leo" below?

An example of an article reference is provided in that section.

Changing an entry

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

If you have found an earlier time stamp for the source than the one listed in the section below "Non-violet sources in Leo" 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.

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

Violet sources in Leo

  1. According to SIMBAD "* alf Leo -- Star in double system". SIMBAD lists * alf Leo as UV (TD1) a B8IV. Wikipedia article on Regulus lists its surface temperature as 12,460 ± 200 K. Its wavelength, temperature pair is (240.6,12460). It's actually an ultraviolet source. Marshallsumter (discuss • contribs) 06:47, 2 April 2014 (UTC)

Non-violet sources in Leo

Oldest records

SIMBAD annotations

For any particular source, the SIMBAD record may indicate that it is not a violet 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 violet source in Leo may have been discovered when the first prism was used to divide starlight into its colors.
  2. If stellar flares have origins similar to solar flares, then flare stars may produce violet waves.

See also

References

  1. ↑ 50.9.138.49 (21 November 2013). Leo (constellation). San Francisco, California: Wikimedia Foundation, Inc. Retrieved 2018-01-17.
  2. 1 2 Pasachoff, Jay M. (2006). Stars and Planets. Boston, Massachusetts: Houghton Mifflin.
  3. ↑ Tamra Andrews (Oxford University Press 2000) Dictionary of Nature Myths: Legends of the Earth, Sea, and Sky (ISBN 9780195136777).
  4. ↑ Gavin White (2008). Babylonian Star-lore. Solaria Pubs. p. 155.
  5. ↑ Ian Ridpath (1988). Star Tales. James Clarke & Co. pp. 112–114. ISBN 9780718826956.
  6. 1 2 3 4 Janet Parker; et al., eds. (2007). Mythology: Myths, Legends and Fantasies. Struik. pp. 121–2. ISBN 9781770074538.

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

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