Studying Young Stars - Revision history

Rebull at 22:21, 23 March 2023

2023-03-23T22:21:40Z

Rebull at 23:19, 31 July 2020

2020-07-31T23:19:38Z

Rebull at 23:17, 31 July 2020

2020-07-31T23:17:36Z

Rebull at 00:17, 31 July 2020

2020-07-31T00:17:36Z

Rebull: /* Overview */

2015-08-25T22:09:03Z

Overview

Rebull: /* Real science vs. textbook science */

2015-08-25T22:07:33Z

Real science vs. textbook science

Rebull at 19:27, 26 December 2012

2012-12-26T19:27:23Z

Rebull at 20:08, 17 May 2012

2012-05-17T20:08:46Z

Rebull at 20:08, 17 May 2012

2012-05-17T20:08:35Z

Rebull at 04:12, 11 May 2012

2012-05-11T04:12:26Z

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 =Young stars in general: Introduction to (low-mass) star formation=
-''Also see this [http://coolcosmos.ipac.caltech.edu/resources/star_formation/ longer somewhat more technical intro to star formation], which I wrote for Cool Cosmos.''
+''Also see this [http://coolcosmos.ipac.caltech.edu/resources/star_formation/ longer somewhat more technical intro to star formation], which I wrote for Cool Cosmos.  https://web.ipac.caltech.edu/staff/rebull/starform/ This content too is the "story of star formation" if that cool cosmos link is dead. ''
 ==Overview==

← Older revision		Revision as of 23:19, 31 July 2020
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	Nomenclature is a nightmare, as it is in so many parts of astronomy. See http://lanl.arxiv.org/abs/0901.1691v1 for examples of real-life flailing around with the wording.		Nomenclature is a nightmare, as it is in so many parts of astronomy. See http://lanl.arxiv.org/abs/0901.1691v1 for examples of real-life flailing around with the wording.
−
−	~~=Young stars in general: [[Finding cluster members]]=~~
−
−	Spitzer is so sensitive that it easily sees things at the far reaches of the Universe with only a few seconds' integration. When studying clusters of stars, not just with Spitzer, one of the first major goals is to figure out which objects are truly cluster members and which are not. This page has a discussion of how to find members of young clusters in general.
−
−	~~=Young stars in general: [[Monitoring young stars]]=~~
−	~~The IC 2118 team has embarked on a campaign to monitor some of the candidate TTauri stars that we found using Spitzer data. They are using ground-based telescopes to see if the stars vary.~~
−
−	~~=Young stars in general: [[Taurus catalog]]=~~
−	~~The Taurus Molecular Cloud is one of the nearest star forming regions at only 140 pc away. This page has a catalog of fluxes for these young stars.~~
−
−	~~=Young stars in general: [[Pre-main sequence evolution]]=~~
−	~~Basic introduction to pre-main sequence evolution.~~

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-=Brief philosophical notes from Luisa=
+=Why should anyone care about young stars?=
 *Understanding star formation includes understanding how planets form, including planets like Earth.
 *Star formation is the "happening field" right now!  TONS of new discoveries happening all the time, many driven by Spitzer.

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 =Brief philosophical notes from Luisa=
-==Real science vs. textbook science==
 ==Why should anyone care about young stars?==

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 The star’s life so far has been governed by the continuous inward pressure of gravity. The gravitational pressure keeps compressing the gas into a smaller and smaller volume, making it hotter and hotter in the core. As soon as the temperature in the core of the protostar becomes great enough, nuclear fusion begins.  When this nuclear fusion begins, finally the star has a way to "fight back" against gravity. So much energy is released in this reaction that it enables the star to "push back" with an outward radiation pressure that balances the inward push of gravity. The protostar is now a full-fledged star, fusing hydrogen into helium in its core. (f) The star will stay the same size until it runs out of nuclear fuel in the core (all of the hydrogen has been converted into helium). Then, the pressure from gravity takes over again, pushing in on the star.
-'''Movies!''' -- The sequence of star formation described above can also be visualized with some movies created by the Spitzer public affairs group.  First [http://coolcosmos.ipac.caltech.edu/resources/star_formation/index.html#flash_video_player_01 form grains in the disk] (note that the grains are distinctly green because they are olivine, like green sand beaches in Hawaii, and the grains get covered in ice).  Then [http://coolcosmos.ipac.caltech.edu/resources/star_formation/index.html#flash_video_player_02 form a planet that clears a gap in the disk].  Next,
+'''Movies!''' -- The sequence of star formation described above can also be visualized with some movies (ARTIST CONCEPTIONS!) created by the Spitzer public affairs group.  First [http://coolcosmos.ipac.caltech.edu/resources/star_formation/index.html#flash_video_player_01 form grains in the disk] (note that the grains are distinctly green because they are olivine, like green sand beaches in Hawaii, and the grains get covered in ice).  Then [http://coolcosmos.ipac.caltech.edu/resources/star_formation/index.html#flash_video_player_02 form a planet that clears a gap in the disk].  Next,
 [http://coolcosmos.ipac.caltech.edu/resources/star_formation/index.html#flash_video_player_03 this is what happens when you form many planets at once] - there are many gaps formed at once. (Where else in the Solar System have you seen this physics before? [http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feiImageID=112884 stumped?]) Of course, it can get crowded in these protoplanetary disks, so [http://coolcosmos.ipac.caltech.edu/resources/star_formation/index.html#flash_video_player_04 occasionally stuff hits each other], creating a second generation of dust.  When this happens, [http://coolcosmos.ipac.caltech.edu/resources/star_formation/index.html#flash_video_player_05 the dust gets smeared out into a ring], and there can be many collisions that create transient dust, e.g., dust that comes and goes depending on when you look.  Finally, [http://coolcosmos.ipac.caltech.edu/resources/star_formation/index.html#flash_video_player_07 you end up with a fully-fledged planetary system], but you have the remnants of the protoplanetary disk left in the outer reaches of the system.  (What do we call this in our Solar System? hint: not the asteroid belt.  out farther than that -- see in the movie, we go out well past a "jupiter".)

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 ==Real science vs. textbook science==
 *Science (history) as presented in textbooks may seem a never-ending series of right answers.  Real science has a lot of dead ends as we struggle to find out what the ‘right answer’ is.
-*Science problems in textbooks have well-defined problems, specific methods you’re supposed to use to solve them, and right (exact) answers (1.2 can be wrong when 1.3 is right).  Real science is not quite “made up as you go along” but it may feel that way in the coming days.  Different people approach the same problem in different ways, and many answers can be right (1.2 and 1.3 can both be right).  '''The only way you know it’s the right answer is if you believe that everything you did to get there is right.'''  Take a moment and really think about that. That's probably a paradigm shift in the way you normally approach science.  Throughout ALL of this wiki, this process, this experience (and probably life in general), you should always be thinking about what you're doing, and not doing anything blindly just because someone tells you to do so.
+*Science problems in textbooks have well-defined problems, specific methods you’re supposed to use to solve them, and right (exact) answers (1.2 can be wrong when 1.3 is right).  Real science is not quite “made up as you go along” but it may feel that way in the coming days.  Different people approach the same problem in different ways, and many answers can be right (1.2 and 1.3 can both be right). This is not the same as 'there is no right answer.' There is a right answer. But, '''the only way you know it’s the right answer is if you believe that everything you did to get there is right.'''  Take a moment and really think about that. That's probably a paradigm shift in the way you normally approach science.  Throughout ALL of this wiki, this process, this experience (and probably life in general), you should always be thinking about what you're doing, and not doing anything blindly just because someone tells you to do so.
 ==Why should anyone care about young stars?==

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 {| cellpadding="2"
 | [[Image:classI.png]]
-|This Class I SED is the next stage.  Now there is a warmer blackbody corresponding to the central object, but most of the energy is still coming from the dusty cocoon around the star (which is reprocessed emission from the central object).  The "bite" that is at about 10 microns tells us that there are silicates (beach sand) in the dust around the star.  About this time is when the rate of accretion slows.  The envelope is now about 0.1 Msun.  The age of the object is about <math>10^5</math> years.
+|This Class I SED is the next stage.  Now there is a warmer blackbody corresponding to the central object, but most of the energy is still coming from the dusty cocoon around the star (which is reprocessed emission from the central object).  The "bite" that is at about 10 microns tells us that there are silicates (beach sand) in the dust around the star.  About this time is when the rate of accretion slows.  The envelope is now about 0.1 Msun.  The age of the object is about <math>10^5</math> years. (Note that there is now a Flat class between I and II -- see notes below.)
 |}

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 The Taurus Molecular Cloud is one of the nearest star forming regions at only 140 pc away. This page has a catalog of fluxes for these young stars.
-=Young stars in general" [[Pre-main sequence evolution]]=
+=Young stars in general: [[Pre-main sequence evolution]]=
 Basic introduction to pre-main sequence evolution.

← Older revision		Revision as of 20:08, 17 May 2012
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	=Young stars in general: [[Taurus catalog]]=		=Young stars in general: [[Taurus catalog]]=
	The Taurus Molecular Cloud is one of the nearest star forming regions at only 140 pc away. This page has a catalog of fluxes for these young stars.		The Taurus Molecular Cloud is one of the nearest star forming regions at only 140 pc away. This page has a catalog of fluxes for these young stars.
		+
		+	=Young stars in general" [[Pre-main sequence evolution]]=
		+	Basic introduction to pre-main sequence evolution.

← Older revision		Revision as of 04:12, 11 May 2012
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	=Young stars in general: [[Monitoring young stars]]=		=Young stars in general: [[Monitoring young stars]]=
	The IC 2118 team has embarked on a campaign to monitor some of the candidate TTauri stars that we found using Spitzer data. They are using ground-based telescopes to see if the stars vary.		The IC 2118 team has embarked on a campaign to monitor some of the candidate TTauri stars that we found using Spitzer data. They are using ground-based telescopes to see if the stars vary.
		+
		+	=Young stars in general: [[Taurus catalog]]=
		+	The Taurus Molecular Cloud is one of the nearest star forming regions at only 140 pc away. This page has a catalog of fluxes for these young stars.