View Full Version : Can someone point me to an authoritative astronomy textbook

2006-Jun-10, 05:40 PM
that gives the definitive answer to a question that I need resolved...

What is the difference between "solar system" "stellar system" and "planetary system"?

The reason I need to know is that a particularly obsessed and self-assured Wikipedian with whom I have delveloped something of a spitting rivalry is convinced he knows the answer, and has revised every single relevant Wiki article to reflect this view. As yet, however he has provided no source for his definition and his whole enterprise smacks faintly of prozyletising.

I had always been under the impression that the definitions fell as follows:

Solar system: our system

planetary system: a generic solar system

star system or stellar system: a multi-star system

He, however, believes that

solar system: our system

star system or stellar system: a generic solar system

planetary system: the body of planets and other material associated with the star.

We can't both be right, and I really need to know. To paraphrase Peter Venkman, if I'm wrong nothing happens. I go to jail (metaphorically) peacefully, quietly, I'll enjoy it. But if I'm right, and we don't stop this thing, then we would have failed to save the minds of millions of defenceless schoolkids.

2006-Jun-10, 06:20 PM
Well, if I were to nit-pick this one:
Solar system = our system since it is the system dominated by Sol
Stellar system = generic system, since it can be dominated by any star
Jovian system = system of moons, etc dominated by Jupiter
Planetary system = system of moons, etc dominated dominated by any planet

Stellar associations should be characterized by something more descriptive of their relationship than "star system" - perhaps binary star system, open cluster, globular cluster, etc. Will you get a "definitive" answer? Probably not - remember that words moderate in meaning depending on context, and if you have already descibed an open cluster, then refer to it as a "stellar system", most people will understand what you intended to say.

Ara Pacis
2006-Jun-10, 06:31 PM
I don't know how often professional astronomers (versus amateurs) post on this board. Have you emailed the BA directly? I doubt there is an authoritive textbook out there since even they may disagree or be out of date with new discoveries, theories, and debates.

Google '>stellar system" brian marsden<.


And as we look out beyond the solar system, we do see planets going around other stars. A lot of these are being discovered, maybe 100 or so being discovered over the last decade or so. They are bona fide planets. They go around stars. There's at least one, if not a couple, out there that don't seem to be going around stars. They've perhaps escaped from a stellar system. And the feeling of the International Astronomical Union is actually, if they're not currently orbiting a star, then they're not planets. And that's a little odd. Because they're the same kind of body. What if one of the planets in the solar system escaped? It's rather difficult to do that, but it could happen. Would it then no longer be a planet?

You might also google >define stellar system< to get some interesting results.
This PDF (http://www.stsci.edu/science/starburst/Preprints/galage99.pdf) writes about stellar systems as systems of stars.

Age-Dating of Young Stars and Stellar Systems
Claus Leitherer
Space Telescope Science Institute1, 3700 San Martin Drive, Baltimore,
MD 21218
Abstract. This review addresses properties and unresolved issues of
stellar systems whose ages are young in comparison with a Hubble time.
In most cases, the energy production in such systems is determined
by massive, short-lived stars. These stars track the most recent star-
formation history in stellar clusters and galaxies. Due to their intrinsic
brightness, even relatively few such stars are observable at cosmological
distances. I discuss the current state of our understanding of massive stars
and how uncertainties affect the interpretation of young stellar systems
and galaxies.

2006-Jun-10, 08:45 PM
To the extent that there is a traditional usage among research astronomers, "stellar systems" has meant binary and multiple stars, star clusters, and galaxies. As a case in point - over about a 25-year span from maybe 1960-1975, the University of Chicago published an authoratative 9-volume compendium on astronomy beyond the solar system - volumes included Telescopes, Astronomical Techniques, Basic Astronomical Data, Stellar Atmospheres, Nebulae and Interstellar Matter, and Galaxies and the Universe. Two volumes, including the one dealing with binaries, were never atually published, leading to an odd numbering system. Anyway, the series title was Stars and Stellar Systems, with nary a mention of anyone else's planets in the set. If someone insists on calling sets of planets around other stars "stellar systems", they are then left without a generic name for most of the things studied in stellar dynamics... Grammatically, this does suffer from not having a parallel analog to "solar system", but "planetary system" has taken on that meaning even though it may include things that we don't like to call planets (minor planets, comets, Kuiper-Edgeworth things, Plutinos, whatever we can connect to that Wikipedia thread).

2006-Jun-11, 02:48 AM
I'm guessing an astronomy textbook will be of no use, because I suspect there is no formal definition of these terms, just like there is no definition of a planet. Whatever definition you get is whatever some person or author believes it should be. Maybe it can be an addendum to the agenda of the "planetary defintion committee" of the IAU in Prague.

Tobin Dax
2006-Jun-11, 10:53 PM
Is it me, or was there a glitch in the Matrix? I swear I've answered this before for you, parallaxicality. :)
I'd tend to agree with him, though. The solar system is, by definition, our Sun's system. However, it has been misused enough that it also means extrasolar star systems with planets. (We do this with moons/satellites, too.) Star/stellar system is definitely most often used with multiple bound stars. I think a logical extension is to use star system to mean the objects gravitationally bound to that star. Likewise, a planetary system is objects (primarily) gravitationally bound to the planet. As turbo-1 pointed out, we already use these conventions when we say solar system (referring to us), Jovian system, and even Earth-Moon system. Planetary system tends to be used both ways, but I think his way makes more sense.

2006-Jun-11, 11:00 PM
FWIW, I remember a Space.com article discussed this very subject, including opinions from professional astronomers. Here it is: http://www.space.com/scienceastronomy/mystery_monday_031215.html

Tobin Dax
2006-Jun-12, 04:51 AM
FWIW, I remember a Space.com article discussed this very subject, including opinions from professional astronomers. Here it is: http://www.space.com/scienceastronomy/mystery_monday_031215.html

Boy, I'm glad I didn't say "Vegan System" above. :) (I almost did.)

2006-Jun-12, 07:05 AM
Hm. I really don't think I can take that much ambiguity to this guy and challenge him with it. He's convinced he's right, which makes him immovable in the face of anything less then words of Absolute Law etched in obsidian by the power of the Old Ones.

2006-Jun-14, 06:17 PM
Related to the topic, I recall Heinlein in a book calling a bright, nebulous "river" of stars seen from the lesser Magellanic cloud "a milky way, but not The Milky Way". That does seem more reasonable to me than calling the celestial image "the lesser Magellanic cloud". Same kind of situation. I'd suggest "solar system" is generic but "Solar System" is our own. Most Google entries do suggest "stellar system" is a system of stars.

Ara Pacis
2006-Jun-14, 10:56 PM
Does your nemesis need to present evidence other than his opinion?

2006-Jun-15, 12:44 AM
Well, it's Wikipedia, so, in truth, no. Kinda the flaw with the whole concept really. All he needs to be is more willing to sit in front of his computer screen for hours on end than I am.

2006-Jun-15, 12:59 AM
Well, it's Wikipedia, so, in truth, no. Kinda the flaw with the whole concept really. All he needs to be is more willing to sit in front of his computer screen for hours on end than I am.

I believe Wikipedia has volunteer moderators who will get involved in the case of "edit wars". They can lock a page if it turns out to be necessary, or ban a person who edits after a "do not edit" warning


2006-Jun-15, 02:57 AM
Formally yes, you need references to all you put on.
If he doesn't have a reference and repeatedly reverts a change that includes a reference then there's a strong case for moderation, which can lead to the page being locked or him being banned, just be very sure to keep everything civil and polite.

Wayne Smith and his amazing puppetshow, if people remember him, got himself plus multiple sockpuppets banned on Wikipedia for something similar.