First microwave source in Cepheus

From Wikiversity
Jump to navigation Jump to search
This image shows the Cepheus molecular cloud complex as seen through the glow of carbon monoxide (CO) with Planck (blue). Credit: ESA/Planck Collaboration.

The first microwave source in Cepheus is unknown.

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

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

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

The early use of sounding rockets and balloons to carry microwave detectors high enough may have detected microwaves 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 microwave astronomy looking for the first astronomical microwave source discovered in the constellation of Cepheus.

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

If stellar flares have origins similar to solar flares, then flare stars produce microwaves.

First step[edit]

The first step is to succeed in finding a microwave source in Cepheus.

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 microwave 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 microwave-source observers.

Sources[edit]

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 microwave sources may be included in the Science section of the lecture/article microwave astronomy.

Traveling microwave sources[edit]

Many microwave 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[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.

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

Cepheus[edit]

This is an image of the International Astronomical Union (IAU) sky map of the constellation Cepheus. Credit: IAU and Sky & Telescope magazine (Roger Sinnott & Rick Fienberg).
Cepheus is depicted in Urania's Mirror, a set of constellation cards (c. 1825). Credit: Sidney Hall, Richard Rouse Bloxam and Adam Cuerden.

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

Cepheus is not a constellation of the zodiac. "It is named after Cepheus, King of Aethiopia".[1]

"It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy".[1]

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.

"Cepheus was the King of Aethiopia. He was married to Cassiopeia and was the father of Andromeda, both of whom are immortalized as modern day constellations along with Cepheus.[2]"[1]

The modern constellation of Cepheus lies across one of the quadrants symbolized by the The Black Tortoise of the North (北方玄武, Běi Fāng Xuán Wǔ), and Three Enclosures (三垣, Sān Yuán), that divide the sky in traditional Chinese uranography.

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

Searching catalogs[edit]

In the lecture microwave astronomy in its science section is a list of older catalogs of microwave 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 microwave sources to see if any may be within Cepheus.

If you find any that are, skip down to the section Microwave sources in Cepheus 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[edit]

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

Wikipedia sources[edit]

A. Constellation article

Under "Notable features" in the Wikipedia article on the constellation Cepheus is the list of stars in Cepheus. Click on this link. In the table of this Wikipedia article is α Cep (Alderamin}. To the right are coordinates:

Right ascension (RA): 21h 18m 34.7715s and Declination (Dec): +62° 35′ 08.061".

Find these coordinates on the Cepheus map at the right.

To evaluate the star as a microwave source, skip ahead to section "Microwave sources".

B. Wikipedia search

Another way to look for microwave sources in the constellation is to perform a search on Wikipedia. Try "microwave Cepheus" without the quotes. This yields 353 returns which include an outline of astronomy, several musical groups, and many entries that mention Cepheus and microwaves.

The outline of astronomy names no microwave sources.

Scroll down the list of 353 looking for some clear text stating that a microwave source in Cepheus is discussed, like Astrophysical maser.

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

SIMBAD sources[edit]

Another way to find possible microwave sources in Cepheus 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(21 18 34.7715 +62 35 08.061,10m)", 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 Cephei, 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: 8" should appear. Click "Back" to see the tan box again.

Adding an object type such as & otype='Rad' to the region request reduces the returned number to those that are radio (possible microwave) sources, zero within 10 m of alpha Cephei. Using 10d instead with & otype='Rad' yields 2405 radio (possibly some microwave) sources. Many of the otypes listed at Object classification in SIMBAD may contain microwaves stars, but may not state that any are microwave sources. Other otypes of microwave sources include Rad (radio-source), mR (metric radio-source), cm (centrimetric radio-source), mm (millimetric radio-source), smm (sub-millimetric source), HI (HI (21 cm) source, rB (microwaves burst), rG (microwaves galaxy), or Mas (maser). Using "otype='cm'" without quotes yields 5.

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, including 'cm'.

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

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

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

SAO/NASA Astrophysics Data System[edit]

In the naming of sources per constellation, the genitive is in common use. For Cepheus, the genitive is Cephei.

Click on the SAO/NASA Astrophysics Data System link below in the "External links". Try "Cepheus microwaves" without the quotes, or "alpha cephei" with quotes, followed by microwaves. The first returns 56 primary source articles that may contain microwave sources in Cepheus. The second returns zero.

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

If it does not try another bibcode link.

Microwave sources[edit]

There are several ways to evaluate a microwave source for the constellation Cepheus.

Wikipedia sources[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 microwaves. Does the article mention whether or not the source is a microwave 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 microwave source in Cepheus edit the "Non-microwave sources in Cepheus" section near the bottom of the page with an entry similar to "# Alpha Cephei 25 December 2013 at 20:12 Wikipedia article "Alpha Cephei", 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 microwave source in Cepheus edit the section below "Microwave sources in Cepheus" with a similar entry.

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

The Wikipedia article on Alpha Cephei mentions, "Alpha Cephei (α Cep, α Cephei) is a second magnitude star in the constellation of Cepheus near the northern pole.",

"Alderamin is a white Class A star, evolving off the main sequence into a subgiant, probably on its way to becoming a red giant as its hydrogen supply runs low." and "Given a surface temperature of 7,740 Kelvin, stellar models yield a total luminosity for the star of about 17 times the luminosity of the Sun."

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

Is alpha Cephei a microwave star, or a microwave source?

Wikimedia commons[edit]

Another possible website for microwave sources is Wikimedia Commons. Try entering "microwaves Cepheus" without the quotes.

This returns nothing.

SIMBAD sources[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, "02 02 02.820 +02 45 49.54".

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 "Cep".

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 6314 otype='cm' listed in SIMBAD. Plotting them may be helpful or scanning them using +62 with your browser may eventually reveal at least one microwave source.

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

SAO/NASA Astrophysics Data System sources[edit]

If the abstract states that a microwave source in Cepheus is detected or studied, consider entering it in the section "Microwave sources in Cepheus" below.

Abstract time stamp[edit]

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

Challenging an entry[edit]

Any entry in either the section "Microwave sources in Cepheus" or "Non-microwave sources in Cepheus" 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[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 microwave source?

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

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

SAO/NASA Astrophysics Data System challenge[edit]

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 microwaves actually occurred. Such a record may provide an earlier time stamp.

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 sources[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 microwaves to see if the source has a reference indicating it is a microwave source source. And, look for the earliest one. Compose an entry using the primary source.

SIMBAD test sources[edit]

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 "Microwave sources in Cepheus". 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[edit]

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 microwave source in Cepheus are detected, which one(s) would you list in the section "Microwave sources in Cepheus" below?

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

Changing an entry[edit]

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

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

Microwave sources in Cepheus[edit]

  1. Cepheus cloud includes an infrared image of this cloud. The image at the top of this resource is also of the cloud in microwaves. According to SIMBAD this cloud is located at RA 22° Dec +76° 30'. --Marshallsumter (discusscontribs) 00:29, 17 November 2015 (UTC)

Non-microwave sources in Cepheus[edit]

Oldest record[edit]

SIMBAD annotations[edit]

For any particular source, the SIMBAD record may indicate that it is not a microwave 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[edit]

  1. The first microwave source in Cepheus may have been found in the 20's.

See also[edit]

References[edit]

  1. 1.0 1.1 1.2 "Cepheus (constellation), In: Wikipedia". San Francisco, California: Wikimedia Foundation, Inc. November 19, 2013. Retrieved 2014-02-01.
  2. Staal, Julius D.W. (1988), The New Patterns in the Sky: Myths and Legends of the Stars (2nd ed.), The McDonald and Woodward Publishing Company, ISBN 0-939923-04-1

External links[edit]