Greetings Sir!

Astrophysics encompasses Stellar Evolution, hence with the form - Stellar Astrophysics that tackles in-depth HRDs, fundamental processes of stars and other massive astronomical objects from its initial stage to the last stage using the natural laws of physics (e.g. Nucleosynthesis, Radiative Transfer etc.). Stellar Astrophysics also takes account for the Asteroseismology wherein numerical modelling of the internal structure takes place using 'evolutionary codes'.

For me, to say at least, there's pretty much no difference between them as they intertwine mostly in a long run. I may have missed out something...But I hope it helps c:

Best regards,

Generich Capuli

CGHA - AAVSO

There are no "official" definitions of astronomy and astrophysics. Some regard astrophysics as a part of astronomy, others think that astronomy is a part of astrophysics. I discuss this in the chapter "Astronomie vs. Astrophysik" in the history of astronomy paper "Friedrich Wilhelm Bessel und die Astrophysik (Friedrich Wilhelm Bessel and astrophysics, see https://www.researchgate.net/publication/338015671, in German). The study of stellar evolution uses elements of classical astronomy (distance ladder based on trigonometric parallaxes), and of course from physics and chemistry. I think that most often it is regarded as a one of the research fields of astrophysics.

Pythagoras, an ancient great Greek philosopher, said, "All is number".

Number + Time = Music,

Music + Space = Astronomy.

Astrophysics is simply that branch of Astronomy which deals with the physical properties of celestial bodies and with the interaction between matter and radiation in the interior of celestial bodies and in interstellar space.

The evolutionary dynamics of stellar structures is an important and integral branch of Astrophysics only.

I agree with Wolfgang Dick about the absence of strict definitions, but in my experience, “astronomy” is largely observational, and “astrophysics” is largely theoretical physics applied to astronomical objects. So stellar evolution theory is certainly astrophysics, but it is a subset. There is also “solar system astrophysics” which has little to do with stellar evolution directly and includes the physics of asteroids, planets, comets, and interplanetary dust. Solar system astrophysics also includes the study of stellar winds and magnetic fields, which are related to stellar evolution. Astrophysics also includes the theory of stellar atmospheres, theory of galactic structure and evolution, etc. So stellar evolution is just one specialty within astrophysics.

John,

Your definitions of astronomy and astrophysics are wide-spread, although it seems to me that the most frequent definition regards astrophysics as a part of astronomy. See., e.g., the Encyclopedia Britannica (https://www.britannica.com/science/astronomy and https://www.britannica.com/science/astrophysics): "Since the late 19th century, astronomy has expanded to include astrophysics, the application of physical and chemical knowledge to an understanding of the nature of celestial objects and the physical processes that control their formation, evolution, and emission of radiation." and "Astrophysics, branch of astronomy concerned primarily with the properties and structure of cosmic objects, including the universe as a whole." This definition of astrophysics includes also observations, not only theory. But all defitions are arbitrary ones, there is no universal definition.

I agree that "astronomy" is largely observational. " That's good. The picture is proof.

Astrophysics today (and before) is a fabrication of nonsense. "Scientists" (based on astronomical observations) fabricate their results without evidence (mostly). They try to be smart.

An example of "evolution".

Small star..........Mass......Temper. K.......Type

Beta Pictoris b.0.0086-0.012...1.724...exoplanet, dist. 11.8 AU

ROXs 42Bb.....0.0086....1.800-2.600..exoplanet, dist. 140 AU

CW Leonis...........0.7-0.9.....2,000.0...C9.5e

Kelu-1...................0.060.......2.020.....brown dwarfs L2

Gliese 570.............0.55........2.700.....M1V

HIP 78530 b..........0.022......2,800.....exoplanet; dist. 710 AU

Lacaillea 9352.......0.503......3.692.....M0.5V

WD 0346 + 246......0.77.......3,800.....white dwarf

Castor C...............0.5992.....3.820.....BY Draconis dwarf stars

HIP 12961...............0.63......3,838.....red dwarf M0V

LP 658-2.........0.45 (0.80)....4.270 (5.180)..white dwarf DZ11.8

HR 9038 Ab.............0.67.....4.620..... red dwarf K3V

Groombridge 1830...0.661...4.759.....G8 subdwarf

HD 134439........... ~ 0.78.....5.136.5..sd: K1Fe-1

AC Herculis.............0.6........5.225......F2pIb

Mu Cassiopeiae......0.74......5.341......G5Vb

L 97-12...................0.59......5.700.0....white dwarf DC8.8

QX Andromedae sec..0.45..6.420.......F6

S Arae....................0.51......6.563.......A3II

HR 4049.................0.56.....7.500.......B9.5Ib-II

GD 356...................0.67.....7.510.......white dwarf DC7

Zeta Cygni B...........0.6.....12,000.......white dwarf DA4.2

40 Eridani B...........0.573...16.500.......white dwarf DA4

Kepler-70...............0.496...27.730......sdB

V391 Pegasi..........0.5.......29.300..... subdwarf star

2MASS J19383260 + 4603591..0.48...29.564....sdBV / M

PG 0112 + 104......0.52 ± 0.05...> 30,000....white dwarf

PG 1047 + 003...~ 0.5......33,500.......sdBe

LS IV-14 116.......0.485....34.950.......sdB0.5VIIHe18

HD 149382..........0.29−0.53...35.000... B5 VI

NSVS 14256825..0.528....42.000,0......sdOB / M V

All the horror of astrophysics is shown in this table.

Weitter Duckss who hurt you?

It is not a singular but the multitudes that prevails in the articles ( "knowledge") in astrophysics.

For example:

„ Below 13 Jupiters, fusion stops altogether. As noted above, the lower end of brown dwarf masses is not known. They quite likely overlap the masses of planets. Planets are by current definition made from the "bottom up," accumulated from dust in disks surrounding new stars, while stars (including brown dwarfs) are made from the "top down," by direct condensation from interstellar gases. But here even the definitions become confused and might overlap as well.“

Brown dwarf & planets..............Mass Jup..........Temperature....Distance AU

CFBDSIR 2149-0403...............................4-7 .......... ~700

PSO J318.5-22........................................6,5........... 1.160

2MASS J11193254-1137466 (AB)........~5-10..........1.012.............3,6±0,9

GU Piscium b..........................................9-13...........1.000.............2.000

WD 0806-661..........................................6-9.............300-345.........2.500

HD 106906 b..........................................11±2...........1.800.................120

1RXS 1609 b...........................................8 (14)........1.800.................330

DT Virginis..............................................8.5 ± 2.5 .....695±60.........1.168

Cha 110913-773444..............................8 (+7; -3).....1.300 -1.400

OTS 44.................................................11,5..............1.700 - 2.300

GQ Lupi b..............................................1 – 36..........2.650 ± 100......100

ROXs 42Bb............................................9.................1.950 ± 100.......157

HD 44627.............................................13 – 14.........1.600 -2400.......275

VHS 1256-1257 b........................11,2 (+9,7; -1,8).......880.................102±9

DH Tauri b.............................................12................2.750.................330

ULAS J003402.77-005206.7................5 – 20...........560 - 600

2M1207b...........................................4 (+6; -1)........1.600±100.............40

2M 044144........................................9.8±1.8...........1.800.................15 ± 0.6

2MASS J2126-8140.........................13,3 (± 1,7)......1.800................6.900

HR 8799 b..........................................5 (+2; -1) .......870 (+30; -70).....~68

HR 8799 c .........................................7 (+3; -2) .....1.090 (+10; -90)....~38

HR 8799 d.........................................7 (+3; -2).......1.090 (+10; -90)....~24

HIP 65426...............................................9,0 ±3,0............1.450.0 (± 150.0)........92

When are lies and nonsense removed from the classrooms?

Are children forced to learn this "knowledge" permanently?

@Cristian Randieri : "The two other physical sciences are chemistry and astronomy".

Even this is debatable.

- On the one hand: most people would regard geology as another, distinct physical science. Many universities have a separate Department of Geology or offer degrees like "BSc in Geology". So that makes a total of 4 physical sciences...

- On the other hand: it can be reasonably argued that chemistry is just applied physics - it is entirely derived from the physics of the atom. And geology is similarly derived from the processes of physics and the products of chemistry. And astronomy needs physics to explain all of its observations. So that makes a total of 1 physical science...

Needless to say, there are only some physicists who maintain that view that physics is the daddy of them all - it's a bit arrogant!

As for the rest of the original question: the subset hierarchy is as follows:

• Physics > Astrophysics > Stellar evolution
• Astronomy > Astrophysics > Stellar evolution

Why do both paths lead to Astrophysics? Because that subdivision is not clear.

Again, think of how these disciplines are organised academically: there are often Departments of Physics, Departments of Astronomy, or Departments of Physics & Astronomy. That puts Astronomy on the same "root level" as Physics. I have yet to encounter a Department of Physics & Astrophysics.

Weitter Duckss "Astrophysics today (and before) is a fabrication of nonsense. "Scientists" (based on astronomical observations) fabricate their results without evidence (mostly)".

"When are lies and nonsense removed from the classrooms?"

You haven't posted a single thing to substantiate any of those wild allegations.

What is your problem with those lists you posted of exoplanets, brown dwarfs & stars?

What is your problem with the contents of the paragraph you quoted from Jim Kaler's http://stars.astro.illinois.edu/sow/star_intro.html ?

Please be specific.

„The planets in Table 3 are in very distant orbits without a significant tidal force impact from their main star and some of them have masses

below 13 MJup- yet

they have temperatures of 1 700 to 2 750°K. Planets with very distant orbits can be significantly warmer than bodies of the same mass or larger in Mercury's orbit and significantly closer to the star (TOI-1338 b 30.2 MJup, distance 0.4491 AU, temperature 724°K vs. ROXs 42Bb 9 MJup, distance 140 AU with a temperature of 1 800 – 2 600°K and td.); Kepler-32b 4 MJup in orbit with a radius of 0.0519 AU has T 569°K (the main star has 0.58 MSun, T 3 900°K), opposite to 2M1207b, which also has 4 MJup in orbit with a radius of 40 AU but has T 1 600°K with colder and smaller star ~0,025 MSun, T 2 550°K .“ (http://article.sapub.org/10.5923.j.astronomy.20200901.02.html)

Do I need to be more precise? How do you explain the identical temperatures of distant planets and brown dwarfs with a mass below 13 M Jupiter and

Star....................size(mass)...Radius......Temperature

R Cygni ………….Cool giant…………/……………2.200

CW Leonis……....0,7 – 0,9……….700………….2.200

IK Tauri……………..1………………451-507………2.100

W Aquilae………….1,04-3……..430-473………1.800

T Cephei…………….1.5-1.8……329 +70 -50…..2.400

S Pegasi………………1,8…………..459-574………2.107

Chi Cygni……….2,1 +1,5 -0,7…348-480……….2.441-2.742

R Leporis……………2,5 – 5………400±90………..2.245-2.290

R Leonis Minoris ..10,18……….569±146……...2.648

S Cassiopeiae.........../………….…930……………..1.800

Еще несколько примеров "крутых" звезд: RW Lmi 2.470; V Hya 2.160; II Lup 2.000; V Cyg 1.875; LL Peg 2.000; LP And 2.040; V384 Per 1.820; R Lep 2.290; W Ori 2.625; S Aur 1.940; QZ Mus 2.200; AFGL 4202 2.200: V821 Her 2.200; V1417 Aql 2.000; S Cep 2.095; RV Cyg 2.675 [15] https://arxiv.org/pdf/1601.07017.pdf

Some planets (and brown dwarfs) have the same temperatures as a large series of C-type, M-type stars.

Where (here) is the evolution that children learn?

Where is here below 13 MJup?

How do you know that claims are "of those wild allegations" if you

Astrophysics is a broad area of physical sciences which provides the bread and butter to many people.

The socio-economic values of the research outcomes in Astrophysics are still questionable.

The chapter of "Stellar evolution" is included elaborately in "Stellar Astrophysics".

Weitter Duckss before invalidate data or estimations, you have to understand where they come from: first, they are *estimations* from a certain model, that can have some assumptions that are not true! (because, like my professor always says, we can't send doctorates in the atmosphere of planets and stars for a thesis, not yet at least); second, there is a thing called thermodynamics and radiative transfer: the "heat in excess" is probably caused by the gravitational collapse or by the radiation of the star and the planet (for some reasons) can't radiate much and remains hotter; or, since no object is isolated from outside, there can be other sources that heat the planet.

If you don't understand something, it doesn't mean it's a non-sense, it does mean you are not educate enough to understand it.

Dear Davide Vatteroni,

If you don't understand something, why are you posting a funny comment?

My comments are for the opposite reasons. I fully understand the material and I have given the answers in over 80 published articles.

I do not use estimates and models that are not true!

That is why my comments are made of evidence, yours are only a reflection of the state of astrophysics (a story without evidence).

If you don’t understand something, ask, don’t give a hollow lecture.

@Weitter Duckss so you make funny of others' work? Oh, yes, you are the best "astrophysicist" in the world and everyone else is just dumb. Please.

Fun fact: if you ever used a code or a equation you didn't write, you surely have used implicitly assumptions and model that are "false", because (astro)physics is full of them

Dear Davide Vatteroni,

I’d love to laugh but it’s not funny.

The truth is I use satire for someone else’s ignorance of matter, who present themselves as authorities in astrophysics.

The truth is and that I do not use assumptions and models that are false. It is also true that astrophysics is full of them.

From my new article:

2. "Black holes"

The black hole topic appeared after a diffraction of light in the atmosphere had been explained as if gravity was refracting light. The statement of one scientific authority was supported and followed by other scientific authorities as they kept upgrading this hypothesis with new constructions. These constructions allowed for everything that was not allowed by the laws of physics.

The field equation solutions of "Karl_Schwarzschild Boundary region of Schwarzschild interior and exterior solution" and "modern" definitions of black holes are diametrally opposite. The common thing they share is they are based not on evidence or observations, but on speculations and assumptions.

The use of Doppler indicates a rotation of an object, not a black hole. A part of an object that rotates towards an observer possesses a blueshift, unlike distancing objects that possess a redshift.

Galaxies and stars rotate.

Fast-rotating galaxies: quasar RX J1131-1231 „X-ray observations of RX J1131-1231 (RX J1131 for short) show it is whizzing around at almost half the speed of light; Spindle galaxy, elliptical galaxy, „possess a significant amount of rotation around the major axis“; NGC 6109 is Lenticular Galaxy, Within the knot, the rotation measure is 40 ± 8 rad m−2

Contrary to: Slow Rotation: Andromeda Galaxy, spiral galaxy, maximum value of 225 kilometers per second; UGC 12591 spiral galaxy, the highest known rotational speed of about 500 km/s,; Milky Way spiral galaxy, 210 ± 10 (220 kilometers per second Sun)

Table 1. Rotation of stars

Star...............................Temperature K............Rotation speed

PSR B0943 + 10............310.000......................1,1 s

PSR 1257 + 12.................28.856.....................6,22ms

Cen X-3............................39.000....................4,84 s

GD 356..............................7 510.................115 min.

RX Andromedae.........40-45 000.................200 km/s

WR 142.........................200 000..............1 000 km/s

LHS 1140...........................3 131..................131 day

DENIS 1048-39..................2 200....................27 km/s

Table 1. Star rotation and temperature

Black holes are the most frequently placed in the centers of galaxies (bulges).

- A super-massive black hole with a diameter of 0.001-400 AU (In Milky Way 0,3 AU, 44 million kilometers). [1.]

- The central part of Milky Way (bulge - "In astronomy, a galactic bulge (or simply bulge) is a tightly packed group of stars within a larger star formation. The term almost exclusively refers to the central group of stars found in most spiral galaxies." ) has a diameter of 3 000 - 16 000 light-years [2] , i.e. 30 000 (from north to south) x 40 000 light –years at the equator (according to other authors). [3] „The bulge of the Milky Way appears to be fairly typical – a slightly flattened sphere of radius ~6,500 light years – while bulge sizes in other galaxies vary from several hundred to several tens of thousands of light years, depending on the type and size of the galaxy.“ From COSMOS - The SAO Encyclopedia of Astronomy › B

- A center of the galaxy (a bulge) consists of 10 million stars per parsec3 (1 pc ≈ 3.261563777 ly), dust, gas and other smaller objects that orbit around stars and planets.

- the radius of Jupiter is 69 911 km.

- the distance of the center of Milky Way from Earth is ~27 000 light-years.

- the distance of Jupiter is 4,2 AU or a few thousand kilometers if a satellite is rotating around it.

For example:

A black hole's size is 100 AU.

A bulge of a galaxy is 10 000 ly or 632 410 000 AU (or 3 066 parsec).

Let's define AU with centimeters, let 100 AU be 1 cm.

If a black hole had a diameter of 100 AU (In Milky Way 0,3 AU), we would then have the value of 1 cm inside a sphere with a diameter of 6 324 100 cm (the volume of a sphere: V= 4/3 pi r^3).

The Nobel's Prize in Physics Award for the detection of a "black hole", with these values set above, seems illogical and irrational and, because of it, the next generations will be compelled to acquire suspicious knowledge.

The density of liquid hydrogen is 0.07 g/cm3 (solid: 0.0763 g/cm3), the density of liquid helium (at m.p.) 0.145 g/cm3. Solid helium has a density of 0.214±0.006 g/cm3 at 1.15 K and 66 atm; the projected density at 0 K and 25 bar (2.5 MPa) is 0.187±0.009 g/cm3. At higher temperatures, helium will solidify with sufficient pressure. At room temperature, this requires about 114,000 atm.[4]

The density of Jupiter is 1.326 g/cm3.

These data undoubtedly state that Jupiter has to have a solid-liquid body, because when a value of 0.214±0.006 g/cm3 (i.e., the density of solid helium) is deducted from 1.326 g/cm3 (i.e., the density of Jupiter), there is a lack of matter, which has the density of 1.112 g/cm3.

Our scientific instruments and our scientists are unable to detect and measure the body of Jupiter (Jupiter has a radius of 69,911 km) covered with gas, but they sure seem able to measure and get a Nobel Prize for "measuring" through a 1 500 to 15 000 light-years-thick layer of matter, consisting of 10 million stars per parsec (In Milky Way 10 000 ly or 3 066 parsec x 10 million stars), dust, gas and other smaller objects that rotate around stars and planets.

3. Chaos in universe?

---------------------------------------------------------

[1] https://en.wikipedia.org/wiki/Black_hole#Physical_properties „General Relativity“ 2010 Robert M. Wald

[2] https://en.wikipedia.org/wiki/Milky_Way#Galactic_Center https://arxiv.org/abs/0903.0946 "Stellar populations in the Galactic bulge" E. Vanhollebeke, M.A.T. Groenewegen, L. Girardi

[3] http://www.astrodigital.org/astronomy/milkywaygalaxy.html https://pages.uoregon.edu/imamura/SCS123/lecture-2/bulge.html "Bulge of the Milky Way" University of Oregon

[4] http://www.chemicool.com/elements/helium-facts.html "Facts about Helium" 2017. Dr. Doug Stewart

[5]. http://www.sciencepublishinggroup.com/journal/paperinfo?journalid=301&doi=10.11648/j.ajaa.20180603.13 American Journal of Astronomy and Astrophysics, Paper Number: 3011059, Paper Title: How are the spiral and other types of galaxies formed? Nov. 2018. W.Duckss

@Weitter Duckss you just attacked the logical fallacy of "appeal to autority" and cite your own book in the same comment? It's not funny, but you make me laugh XD

"Astrophysics is a fabbrication of non-sense" is not satire, it's just you offending the work of hundreds of men and women; also satire is not a way of comunication in science.

Read this: https://yourlogicalfallacyis.com/appeal-to-authority