< Radiation astronomy
Positron astronomy results have been obtained using the INTEGRAL spectrometer SPI shown. Credit: Medialab, ESA.

The first positron source in Phoenix is unknown.

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

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

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

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

This is a lesson in map reading, coordinate matching, and researching. It is also a research project in the history of positron astronomy looking for the first astronomical positron source discovered in the constellation of Phoenix.

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 positron sources, you'll run into concepts and experimental tests that are actual research.

First step

The first step is to succeed in finding a positron source in Phoenix.

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 positron 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 positron source observers.

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

Traveling positron sources

Many positron 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.

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.

Positrons are a form of radiation that is currently part of subatomic particle radiation intersecting the Earth. More information about radiation is in radiation astronomy.

Phoenix

The constellation Phoenix as depicted in Johan Gabriel Doppelmayr's Atlas Coelestis, ca. 1742.
This is an image of the International Astronomical Union (IAU) sky map of the constellation Phoenix. Credit: IAU and Sky & Telescope magazine (Roger Sinnott & Rick Fienberg).

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

Phoenix was the largest of the twelve constellations established by Petrus Plancius from the observations of Pieter Dirkszoon Keyser and Frederick de Houtman. It first appeared on a 35-cm diameter celestial globe published in 1597 (or 1598) in Amsterdam by Plancius with Jodocus Hondius.

Phoenix was first depicted on a celestial atlas by Johann Bayer in his 1603 Uranometria.

Celestial historian Richard Allen noted that unlike the other constellations introduced by Plancius and La Caille, Phoenix has actual precedent in ancient astronomy, as the Arabs saw this formation as representing young ostriches, Al Ri'āl, or as a griffin or eagle.[1] In addition, the same group of stars was sometimes imagined by the Arabs as a boat, Al Zaurak, on the nearby river Eridanus.[2] He observed, "the introduction of a Phoenix into modern astronomy was, in a measure, by adoption rather than by invention."[1]

"The Chinese incorporated Phoenix's brightest star, Ankaa (Alpha Phoenicis), and stars from the adjacent constellation Sculptor to depict Bakui, a net for catching birds.[3]

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

Searching catalogs

In the lecture/article positron astronomy in its science section is a list of older catalogs of positron 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 positron sources to see if any may be within Phoenix.

If you find any that are, skip down to the section Positron sources in Phoenix 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 positron source listed for the constellation Phoenix. 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 Phoenix is the list of stars in Phoenix. Click on this link. In the table of this Wikipedia article is α Phe. To the right are coordinates:

Right ascension (RA): 00h 26m 17.05140s and Declination (Dec): -42° 18' 21.5539".

Find these coordinates on the Phoenix map at the right.

To evaluate the star as a positron source, skip ahead to section "Positron sources".

B. Wikipedia search

Another way to look for positron sources in the constellation is to perform a search on Wikipedia. Try "Phoenix positron" without the quotes. This yields only 2 returns which include an outline of astronomy and a Sun computer.

The outline of astronomy names no positron sources.

SIMBAD sources

Another way to find possible positron sources in Phoenix 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(00 26 17.05140 -42 18 21.5539,10m)", 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 Phoenicis, with a radius of 10 arcminutes (m), 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: 9" should appear. Click "Back" to see the tan box again.

Adding an object type such as & otype='gam' to the region request reduces the returned number to those that are gamma-ray sources. But, all of the otypes listed at Object classification in SIMBAD may contain positron stars, but do not state positron sources. Usually, positrons annihilate generating 511 keV gamma-rays. A likely choice for a positron source would be a known gamma-ray source.

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', ...).

But, here again no information about possible positron sources is listed.

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

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

SAO/NASA Astrophysics Data System

In the naming of sources per constellation, the genitive is in common use. For Phoenix, the genitive is Phoenicis.

Click on the SAO/NASA Astrophysics Data System link below in the "External links". Try "Phoenicis positron" without the quotes, or "alpha phoenicis" with quotes, followed by positron.

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

If it does not try another bibcode link.

Positron sources

There are several ways to evaluate a positron source for the constellation Phoenix.

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 positrons or gamma rays. Does the article mention whether or not the source is a positron or gamma-ray 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 positron source in Phoenix edit the "Non-positron sources in Phoenix" section near the bottom of the page with an entry similar to "# Alpha Phoenicis 25 December 2013 at 20:12 Wikipedia article "Alpha Phoenicis", 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 positron source or at least a gamma-ray source in Phoenix edit the section below "Positron sources in Phoenix" with a similar entry.

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

The Wikipedia article on Alpha Phoenicis mentions, "Alpha Phoenicis [...] is a spectroscopic binary star system with components that orbit each other every 3848.8 days (10.5 years).[4] The combined stellar classification of the system is K0.5 IIIb,[5] which matches the spectrum of a lower luminosity giant star."

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

Is the primary star of alpha Phoenicis a positron star, or a positron source?

Wikimedia commons

Another possible website for positron sources is Wikimedia Commons, url=https://commons.wikimedia.org/wiki/Main_Page. Try entering "positron Phoenix".

This returns no images of any positron sources in Phoenix.

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, "00 26 17.05140 -42 18 21.5539".

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 "Phe". While using "Mon" for Monoceros locates 45 in the list, "Phe" finds none.

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 shows that no flare stars listed in SIMBAD occur within the right ascension and declination ranges of Phoenix.

Another possibility is to use otype='X' for X-ray sources or otype='gam' or otype='gB' for gamma-ray sources. Either of these may indicate a positron source.

There are 3511 otype='gam' listed in SIMBAD. Plotting them may be helpful or scanning them using -4 with your browser will eventually reveal at least one gamma-ray source that may also be a positron source: IGR J02115-4407.

If you have already found a positron 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 positron source, edit the "Non-positron sources in Phoenix" 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 positron source in Phoenix (did you check the coordinates vs. the map of Phoenix?), make an entry something like the ones in the section "Positron sources in Phoenix".

SAO/NASA Astrophysics Data System sources

If the abstract states that an positron source in Phoenix is detected or studied, consider entering it in the section "Positron sources in Phoenix" 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 positron source on or before the date of publication. The time stamp followed by four ~s for your verification as determiner in the section "Positron sources in Phoenix" completes your entry.

Challenging an entry

Any entry in either the section "Positron sources in Phoenix" or "Non-positron sources in Phoenix" 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 positron 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 positron 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 positrons 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 positrons to see if the source has a reference indicating it is a positron 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 "Positron sources in Phoenix". 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 positron source in Phoenix are detected, which one(s) would you list in the section "Positron sources in Phoenix" 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 positron source?

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

Positron sources in Phoenix

  1. IGR J02115-4407 SIMBAD: "C.D.S. - SIMBAD4 rel 1.218 - 2014.02.18CET02:50:19", "otype='gam'", found by searching the list of gamma-ray sources using "-4". --Marshallsumter (discuss • contribs) 01:57, 18 February 2014 (UTC)

Non-positron sources in Phoenix

Oldest record

SIMBAD annotations

For any particular source, the SIMBAD record may indicate that it is not a positron 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. A first positron source in Phoenix may have been found in the 60's.

See also

References

  1. 1 2 Richard Hinckley Allen (1963) [1899]. Star Names: Their Lore and Meaning (Reprint ed.). New York City, New York: Dover Publications Inc. pp. 335–36. ISBN 0-486-21079-0.
  2. ↑ Lloyd Motz, Carol Nathanson (1991). The Constellations: An Enthusiast's Guide to the Night Sky. London, United Kingdom: Aurum Press. pp. 371–72. ISBN 1-85410-088-2.
  3. ↑ Ridpath, Ian. Phoenix – the Phoenix. self-published. Retrieved August 18, 2013.
  4. ↑ S. Jancart, A. Jorissen, C. Babusiaux, D. Pourbaix (October 2005). "Astrometric orbits of SB^9 stars". Astronomy and Astrophysics 442 (1): 365–80. doi:10.1051/0004-6361:20053003.
  5. ↑ R. O. Gray, C. J. Corbally, R. F. Garrison, M. T. McFadden, E. J. Bubar, C. E. McGahee, A. A. O'Donoghue, E. R. Knox (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.

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