< Radiation astronomy
The graph shows the spatial distribution of ROSAT all-sky survey X-ray sources in the Chamaeleon cloud complex. Credit: J.M. Alcalá, J. Krautter, J.H.M.M. Schmitt, E. Covino, R. Wichmann and R. Mundt.

The first X-ray source in Apus discovered by our X-ray observatory satellites or rockets is unknown.

Above is a sky plot of the X-ray sources detected by the ROSAT all-sky survey in the Chamaeleon star-forming cloud complex. X-ray sources (Xs in the diagram) along the 14:00 h longitude are in the constellation Apus.

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

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

Some of the material and information you'll be introduced to is at the college or university level, and as you progress in finding X-ray sources, you'll run into concepts and experimental tests that are actual research.

To succeed in finding an X-ray source in Apus 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 X-ray 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.

Sources

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

Many X-ray 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 12 of the Zodiac and the constellation Ophiuchus.

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.

X-rays are a form of radiation that is part of the electromagnetic radiation intersecting the Earth. More information about radiation is in radiation astronomy.

Constellations

This is an image of the International Astronomical Union (IAU) sky map of the constellation Apus. Credit: IAU and Roger Sinnott & Rick Fienberg, Sky & Telescope magazine.

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

Apus is a faint constellation in the southern sky, first defined in the late 16th century.

"Apus was one of twelve constellations created by Petrus Plancius from the observations of Pieter Dirkszoon Keyser and Frederick de Houtman and it first appeared on a 35 cm diameter celestial globe published in 1597 (or 1598) in Amsterdam by Plancius with Jodocus Hondius.[1][2][3] Plancius called the constellation "Paradysvogel Apis Indica"; the first word is Dutch for 'bird of paradise,' of genus Pteridophora, but the others are Latin for "Indian Bee," although "apis" (Latin for "bee") is presumably an error for "avis" or "bird".[1][3]

After its introduction on Plancius's globe, the first known depiction of the constellation in a celestial atlas was in Johann Bayer's Uranometria of 1603, where it was called "Apis Indica".[1][3]

When the Ming Dynasty Chinese astronomer Xu Guangqi adapted the European southern hemisphere constellations to the Chinese system in The Southern Asterisms, he combined Apus with some of the stars in Octans to form the "Exotic Bird" (異雀, Yìquè).[4]

The Sun is an X-ray source that travels through the 13 constellations along the ecliptic. Is Apus a constellation that the Sun travels through?

Also, in the Wikipedia article is a list of stars in Apus. What's the difference between a star and an astronomical X-ray source?

Testing a source

There are many web sites that may have an X-ray source listed for the constellation Apus.

Wikipedia sources

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

  1. Right ascension (RA): 14h 47m 51.73s and
  2. Declination (Dec): -79° 02' 41.0".

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

To evaluate the star as an X-ray source, skip ahead to section "X-ray source".

Another Wikipedia source for stars in Apus is the "Template:Stars of Apus", which can be searched by entering "Template:Stars of Apus", without the quotes. Stars already searched may not have had their other designations updated in the template.

SIMBAD sources

Another way to find possible X-ray sources in Apus is to use other 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(14 47 51.73 -79 02 41.0, 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 Apodis, 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: 7" should appear. Click "Back" to see the tan box again.

Add "otype='X'" to the entry so that it reads: "region(14 47 51.73 -79 02 41.0, 10m) & otype='X'", without the outside quotes. Click on "submit query" again. If the result is "0" number of objects, increase the number of arcminutes, or use "1d" which stands for "one degree".

When you find at least one object, change "Return" to "display" by clicking on the circle to its left, then "submit query".

X-ray sources

There are several ways to evaluate an X-ray source for the constellation Apus.

Wikipedia source

Click on the link to the Wikipedia article on Alpha Apodis (α Aps). After you've enjoyed reading about the star, use the 'find' command of your browser to see if this Wikipedia page mentions anything about "X-ray", or "X-rays". Does the article mention whether or not Alpha Apodis is an X-ray source?

What is the current time stamp for the Wikipedia article on Alpha Apodis? [Hint]: look for something like "This page was last modified on 25 December 2011 at 20:12." very near the bottom of the page. For now this is an adequate time stamp.

From reading the Wikipedia article on Alpha Apodis, if you believe the text demonstrates that Alpha Apodis is not an X-ray source in Apus edit the "Non-X-ray source in Apus" section near the bottom of the page with an entry similar to "# Alpha Apodis 25 December 2011 at 20:12 Wikipedia article "Alpha Apodis".", 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.

Is Wikipedia a 'primary source'?

Even though Wikipedia has an article on Alpha Apodis, is it a good place to stop in testing whether Alpha Apodis has been detected as an astronomical X-ray source?

SIMBAD source

Provided under 'External links' at the bottom of this page are a number of helpful links. If your browser allows you to view a second window in parallel with this one, 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 use "alpha Aps", "alpha apodis", or "Alpha Apodis" or
  2. source coordinates: without the quotes "14 47 51.73 -79 02 41.0".

If "alpha apodis" does not work, try "alpha Aps".

The names take you directly to "* alf Aps", but the coordinates yield a list, what's the difference between "* alf Aps" in the table and "Alpha Apodis" on Wikipedia?

If you are looking at the table which lists possible targets, click on the entry "* alf Aps" to look at the entry.

On the page "* alf Aps" read down the left side until you see "Other object types:". To the right of this is a list of other object types that Alpha Apodis is. Look for an X. Is there one in this horizontal list?

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 Alpha Apodis is not an X-ray source, edit the "Non-X-ray source in Apus" section near the bottom of this page and type in an entry similar to "# Alpha Apodis 2012.01.09CET20:10:02 SIMBAD article "* alf Aps".", without the first set of quotes, followed by four ~s.

If your SIMBAD analysis convinces you that you have found an X-ray source in Apus (did you check the coordinates vs. the map of Apus?), make an entry something like the following in the section "X-ray source in Apus".

Challenging an entry

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 an X-ray 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 presently considered close enough to alpha Apodis to be the star.

Wikipedia test source

Further down the SIMBAD page for "* alf Aps" is a list of "Identifiers (23)". Primary source literature may use any of these to include the star in their experimental observations. From the 'External links' near the bottom of this page, try a search with text something like "alpha apodis" "X-rays" or "X-ray".

For some sources, designations such as "HR 5470", "HD 129078", "SAO 257193", or "UBV 12790" may be more productive. If none of these works, try another star.

SIMBAD test source

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 "X-ray source in Apus". 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 Alpha Apodis so far, is it an X-ray source?

If you have found an earlier time stamp for alpha apodis than the one listed in the section below "Non-X-ray source in Apus" 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.

X-ray sources in Apus

  1. 1RXS J143729.3-791432 1999 SIMBAD article "1RXS J143729.3-791432"[5]"the all-sky survey [was] performed during the first half year (1990/91) of the ROSAT mission."[5] Marshallsumter (talk) 00:14, 27 February 2012 (UTC)
  2. Gamma Apodis (gam Aps on SIMBAD) X-ray source 1RXS J163329.7-785341, "the all-sky survey [was] performed during the first half year (1990/91) of the ROSAT mission."[5] Marshallsumter (talk) 00:35, 27 February 2012 (UTC)
  3. 1RXS J143729.3-791432 2012.01.09CET21:26:56 SIMBAD article "1RXS J143729.3-791432". Marshallsumter 22:44, 9 January 2012 (UTC)

Non-X-ray sources in Apus

  1. Alpha Apodis 2012.01.09CET20:10:02 SIMBAD article "* alf Aps". Marshallsumter 20:02, 9 January 2012 (UTC)
  2. Alpha Apodis 25 December 2011 at 20:12 Wikipedia article "Alpha Apodis". Marshallsumter 20:02, 9 January 2012 (UTC)
  3. Gamma Apodis 29 December 2010 at 23:29 from the Wikipedia article. Marshallsumter (talk) 00:22, 27 February 2012 (UTC)
  4. bet Aps 2012.06.03CEST03:01:13 SIMBAD article "LTT 6652 -- High proper-motion Star". Marshallsumter (talk) 01:13, 3 June 2012 (UTC)
  5. Delta Apodis 14 March 2013 at 17:23 from the Wikipedia article. --Marshallsumter (discuss • contribs) 20:02, 21 April 2013 (UTC)
  6. Epsilon Apodis 14 April 2013 at 18:56 from the Wikipedia article. --Marshallsumter (discuss • contribs) 20:07, 21 April 2013 (UTC)
  7. Zeta Apodis 1 March 2013 at 02:52 from the Wikipedia article. --Marshallsumter (discuss • contribs) 20:07, 21 April 2013 (UTC)
  8. Eta Apodis 14 March 2013 at 17:24 from the Wikipedia article. --Marshallsumter (discuss • contribs) 20:10, 21 April 2013 (UTC)
  9. Theta Apodis 27 February 2013 at 09:00 from the Wikipedia article. --Marshallsumter (discuss • contribs) 20:13, 21 April 2013 (UTC)
  10. Iota Apodis 14 April 2013 at 19:46 from the Wikipedia article. --Marshallsumter (discuss • contribs) 20:13, 21 April 2013 (UTC)
  11. Kappa1 Apodis 19 March 2013 at 11:39 from the Wikipedia article. --Marshallsumter (discuss • contribs) 20:18, 21 April 2013 (UTC)
  12. Kappa2 Apodis 14 April 2013 at 19:49 from the Wikipedia article. --Marshallsumter (discuss • contribs) 20:18, 21 April 2013 (UTC)
  13. R Apodis 27 February 2013 at 12:02 from the Wikipedia article. --Marshallsumter (discuss • contribs) 20:54, 21 April 2013 (UTC)
  14. S Aps 2013.04.21CEST22:55:28 SIMBAD article "V* S Aps". --Marshallsumter (discuss • contribs) 20:58, 21 April 2013 (UTC)
  15. MY Aps 2013.04.21CEST22:58:52 SIMBAD article "V* MY Aps". --Marshallsumter (discuss • contribs) 21:01, 21 April 2013 (UTC)
  16. MN Aps 2013.04.21CEST23:01:47 SIMBAD article "V* MN Aps". --Marshallsumter (discuss • contribs) 21:07, 21 April 2013 (UTC)
  17. NO Aps 2013.04.21CEST23:08:29 SIMBAD article "V* NO Aps". --Marshallsumter (discuss • contribs) 21:11, 21 April 2013 (UTC)

Hypotheses

  1. The first X-ray source in Apus may be that portion of the Chamaeleon star-forming region that overlaps into Apus.

See also

References

  1. 1 2 3 Ian Ridpath. Apus, In: Star Tales. Retrieved 10 April 2012.
  2. ↑ Ridpath, Ian (2001), Stars and Planets Guide, Princeton University Press, ISBN 0-691-08913-2
  3. 1 2 3 Tammy Plotner (13 October 2008). Apus. Universe Today. Retrieved 22 April 2012.
  4. ↑ AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 29 日
  5. 1 2 3 Voges, W.; Aschenbach, B.; Boller, Th.; Bräuninger, H.; Briel, U.; Burkert, W.; Dennerl, K.; Englhauser, J.; Gruber, R.; Haberl, F.; Hartner, G.; Hasinger, G.; Kürster, M.; Pfeffermann, E.; Pietsch, W.; Predehl, P.; Rosso, C.; Schmitt, J. H. M. M.; Trümper, J.; Zimmermann, H. U. (September 1999). "The ROSAT all-sky survey bright source catalogue". Astronomy and Astrophysics 349 (9): 389-405.

Further reading

  • Voges, W.; Aschenbach, B.; Boller, Th.; Bräuninger, H.; Briel, U.; Burkert, W.; Dennerl, K.; Englhauser, J.; Gruber, R.; Haberl, F.; Hartner, G.; Hasinger, G.; Kürster, M.; Pfeffermann, E.; Pietsch, W.; Predehl, P.; Rosso, C.; Schmitt, J. H. M. M.; Trümper, J.; Zimmermann, H. U. (September 1999). "The ROSAT all-sky survey bright source catalogue". Astronomy and Astrophysics 349 (9): 389-405. 

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