What is Stellar: Definition and 169 Discussions

A stellar collision is the coming together of two stars caused by stellar dynamics within a star cluster, or by the orbital decay of a binary star due to stellar mass loss or gravitational radiation, or by other mechanisms not yet well understood.
Astronomers predict that events of this type occur in the globular clusters of our galaxy about once every 10,000 years. On 2 September 2008 scientists first observed a stellar merger in Scorpius (named V1309 Scorpii), though it was not known to be the result of a stellar merger at the time.Any stars in the universe can collide, whether they are 'alive', meaning fusion is still active in the star, or 'dead', with fusion no longer taking place. White dwarf stars, neutron stars, black holes, main sequence stars, giant stars, and supergiants are very different in type, mass, temperature, and radius, and so react differently.A gravitational wave event that occurred on 25 August 2017, GW170817, was reported on 16 October 2017 to be associated with the merger of two neutron stars in a distant galaxy, the first such merger to be observed via gravitational radiation.

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  1. J

    Determining the density of a stellar object

    Homework Statement Hello all. I am new to physics but am quite competent in maths and other sciences. I am studying Open University's Exploring Science module and this one question has me stumped. I follow all of the instructions but always come to a completely improbable answer. The...
  2. J

    Is the Universe Losing Mass Through Stellar Energy Conversion?

    as mass is converted to energy in stars, is universe losing total mass?
  3. P

    Stellar Energy Generation and Nucleosynthesis

    Introduction: The evolution of stellar objects is inherently caused by the chemical composition of the star. Internally, thermonuclear reactions leading to the formation of complex atoms lead to a change in chemical composition which in turn will affect the evolutionary position of a star...
  4. J

    Question: Regarding Stellar Spectroscopy Equipment.

    Hi, I am new to this forum but I am an applied physics student and I'm working on a seminar on deep space spectroscopy. My question is actually on the equipment being used for my research. I am using an SBIG ST-7 camera with a DSS-7 spectrograph and I've been running calibration studies with...
  5. R

    Mass Function of Stars in Globular Clusters - 600 M Sun

    Homework Statement Stars in a globular cluster are distributed as a mass function of: \phi(M)=K M^{-2}, such that dN=\phi(M) dM is the stars number in the infinitesimal mass interval. Masses are between a lower limit M_{inf}=0.3 M_{sun} and an upper limit M_{sup}, unknown. The constant K is...
  6. P

    Stellar Astronomy - Measuring surface temp of the Sun

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  7. T

    Astronomy - Determine the sum of the stellar masses

    Homework Statement A double star located at a distance of 10 light years from us. The maximum angle between the stars, as seen from Earth, is 2 arcseconds. (1 arcsecond = 1 / 3600 degrees), we can assume that the stellar orbit is circular and that this angle gives us the real distance between...
  8. atomqwerty

    Solving Stellar Structure: Pressure & Temperature Stratification

    Homework Statement Let be the density given by the expression p = pc(1-r/R) where R is tha radius of the star. Find the stratification for pressure and temperature. Homework Equations Equilibrium eq. dP/dr = -Gm(r)p/r2 Continuity eq. dm/dr = 4*Pi*r2p PS.: p == rho (sorry for not...
  9. Simfish

    What happened to stellar astrophysics?

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  10. PrincePhoenix

    Position of stellar bodies in space.

    Do the sun, moon, Earth etc lie in the same plane? I mean are they at the same level or some bodies are above/below others? If yes than why?
  11. S

    Exploring the Spectra of Stars: Comparing O and M Types

    As we look to the spectra of stars from O to M type, we see that as temprature decreses, the spectral lines become more crowded. Why M-stars have more various elements than O-stars? Is that because of mass or age or what?
  12. M

    Calculating Acceleration of Stellar Engines: A Comparison to Wikipedia Example

    Has anyone here looked at the physics of stellar engines? See http://en.wikipedia.org/wiki/Stellar_engine for an overview. In particular, I have done a simple calculation for the acceleration due to light pressure of a "Shkadov thruster", which is a reflective shell on one side of a star that...
  13. R

    Stellar formation and evolution

    I know the general accepted theory to the birth of our solar system. One or more nearby stars went supernova and the shock waves caused our gas cloud to collapse forming our solar system. However, i wanted an opinion from those with more knowledge on a hypothesis that seems to make some sense...
  14. A

    Stellar Collisions: Modeling Neutron Star & White Dwarf Interactions?

    Does it exist an accurate model about what happen when two stellar bodies collide?. I'm referring to the kind of collision between neutron stars, white dwarfs. I was wondering if that collision could produce a new kind of object. For example: a white dwarf into a neutron star, and a neutron star...
  15. C

    Need help understanding Collapsed Configurations of stellar Mass

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  16. P

    Books on Cosmology of Stellar Objects

    I have been reading Kip Thorne's marvelous book ""Black Holes and Time Warps" to familiarize myself with general relativity. Along the way, I have found he discusses many fascinating cosmological topics that I would like to explore further. I am looking for books about the various types of...
  17. P

    Stellar Classification of White Dwarfs

    OK recently I found a really old table stars based on partally on Yerkes Classification system with a small section on white dwarf stars. It has the stars organized into groups labeled DO, DA, DB, DF, DG, DK, and DM. However, I remember that the current classification system for white dwarf...
  18. T

    Stellar Pancaking, anyone familiar with it?

    I have a report to write about it, and i was wondering if anyone was aware of any relevant material/journals ideally. Any material on Tidal forces would be useful too. Or if you know anything personally on this subject matter, i wouldn't mind reading a rant about it :)
  19. Matterwave

    Can Supernovas Disrupt Entire Stars Without Remnant?

    Hey guys, quick question, I know that the usual stellar remnants are the White Dwarf, Neutron Star, and Black Hole, depending on the initial mass of the Star. I was wondering if some Super-Novas could be so catastrophic that the entire star, including its degenerate core was disrupted so that...
  20. Q

    Reccomend a stellar database for my software program?

    hi. I'm creating a game where the main part is exploration. i want a database with the milky way's stars (though I'm not sure how many stars my program will be able to handle at this point) and for the other nearby galaxies i would randomly generate such a database of stars for those galaxies...
  21. I

    Math Stellar numbers IB portfolio

    Homework Statement Its a series of triangles, the data table being n-# 1-1 2-3 3-6 4-10 5-15 I need a general equation in terms of n. Homework Equations The Attempt at a Solution I can't really find anything. The solution has to be non-recursive, and i can find a bunch of...
  22. N

    Could advanced technology artificially accelerate the evolution of our sun?

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  23. C

    How Do You Calculate Orbital Speed in Different Galactic Density Models?

    Homework Statement Calculate \Omega(r) and v(r) for the following density models: (a) all the mass M is at the center of the galaxy; (b) a constant density adding up to a mass M(R0) at the Sun’s orbit and no mass beyond. Homework Equations M(r) = v(r)2r/G The Attempt at a...
  24. thenewmans

    Unravelling the History of Stars: 14 Billion Years

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  25. Z

    Q. about Bradley's Stellar Aberration

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  26. M

    Stellar Evolution - Detailed Colour Magnitude (HR) Diagram

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  27. S

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  28. H

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  29. nicksauce

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  30. W

    Stellar orbits around the milky way.

    I was just thinking about how this is done. I have looked online and I can't find a none mathematical explanation. If I am getting it right, we get the orbits by measuring the radial and tangential velocities of several stars relative to our sun. I thought the tangential velocity was...
  31. R

    Stellar Formation, Life, Death - Temp, Radius, Luminosity

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  32. A

    Question concerning Michelson stellar interferometer

    Hello there, I have a question concerning Michelson stellar interferometer. It is about stars ejecting mass in a thin luminous shell of gas expanding to a size greater than that of star itself. So it says in the exercise: a michelson interferometer is used as a fourrier transform...
  33. cepheid

    Virial Theorem in Stellar Dynamics

    After reading in Longair's Galaxy Formation through the derivation of the virial theorem in the context of a dynamical system in equilibrium consisting of "point masses" interacting only through gravity, I proceeded to try to understand his comments on how the theorem can be applied in order to...
  34. L

    Red - blue shifts and stellar rotation

    When considering the speed of objects revolving around a galactic boundary and the gravitational confluence at the center of the galaxy, it would appear that all objects would be spiraling toward the center. If an object is spiraling toward that center, then it would appear that light from these...
  35. I

    What does it mean the number after the stellar class? Magnitude?

    What does it mean the number after the stellar class? Magnitude?
  36. V

    Superwind phase in stellar evolution

    why is there very rapid mass loss in the superwind phase. my notes simply say "because the envelope attains positive binding energy". Firstly, how can binding energy be positive by definition?! Secondly, I am not entirely sure what the lecturer is talking about? what makes the envelope...
  37. V

    Stellar Evolution: After Hydrogen Exhaustion

    why after hydrogen exhaustion (of low mass stars) does the the core become isothermal. (according to my notes) I mean, after exhaustion, its all helium, and it keeps on contracting right? So by the virial therem it must heat up (so by definition, it is NOT isothermal)! Indeed it must do so...
  38. A

    Solving Stellar Wind Virial Theorem for Exam

    Homework Statement Hi, i have 2 past exam questions that i need to be able to solve for my exam in 3 days time: consider the portion of a stellar wind of mass density rho, pressure p, temperature T and velocity v between the radii r=R_i = 10R_* and r=R_o = 100R_* where R_* is the radius...
  39. A

    Stellar Wind Virial Equations

    Homework Statement Hi, i have 2 past exam questions that i need to be able to solve for my exam in 3 days time: consider the portion of a stellar wind of mass density rho, pressure p, temperature T and velocity v between the radii r=R_i = 10R_* and r=R_o = 100R_* where R_* is the radius...
  40. S

    Superbubbles from shock waves from supernova or stellar winds?

    Can someone explain to me how shock waves from supernova or stellar winds can generate a superbubble? Does the energy from the shock get converted to thermal energy through compression?
  41. B

    Advantage of measuring stellar parallaxes from Mars rather than Earth?

    Is there advantage of measuring stellar parallaxes from Mars rather than from Earth? Would it be more accurate than from Earth? Thanks
  42. stevebd1

    Gravity for a stellar black hole

    I'm currently looking at the various gravity gradients (tidal stresses) for black holes and I've realized that in respect of small stellar black holes, as you approach the event horizon, not only does the gravity increase but it (appears) to exceed c. For example, for a 3 sol black hole, the...
  43. Simfish

    Stellar Evolution: Pathways & Perturbations

    stellar evolution pathways...? I find this especially interesting since the trajectories of stars on the HR diagram are more or less based on this assumption. But obviously, small perturbations can lead to major changes in the long-run. But it seems that most of those changes involve only...
  44. Holocene

    Typical stellar distances of visible stars in the Milky Way

    How far away is the average star in the night sky? I mean, can we see stars that are on the other side of the galaxy? Perhaps most of the visible stars are maybe just a few dozen light years away?
  45. R

    What Are Some Recommended Graduate Level Texts on Stellar Spectroscopy?

    I seek a suitable and current graduate level text on astronomical spectroscopy. The desired emphasis is on stellar sources. I would appreciate recommendations.
  46. V

    What colors represent different stages of a star's life cycle?

    Hello I am a student in high school and my physics teacher is a complete idiot. He just gave us a project to draw the life cycle of stars without even teaching the class. I am completely lost. Can someone help me draw the life cycle of stars that includes small: G-yellow K-orange...
  47. J

    Applying the Virial Theorem to Stellar winds

    Hello, In the process of revising for an exam I have, I am having difficulty with this question. "Consider an isotropic stellar wind of mass density rho, pressure p, temperature T and velocity v that has reached to a distance r=R_w from the centre of a star. The star has mass M* and...
  48. V

    What are the Detailed Steps and Mechanisms of Stellar Evolution?

    I am new to astronomy, though really interested in it Just read up on stellar evolution from multiple sources, but have some questions about it Let me summarize the theory of stellar evolution 1. gas clouds collapse due to multiple mechanisms, e.g. shock wave, collision of clouds... 2. the...
  49. R

    Stellar Population in Milky Way

    Hey folks, I'm currently at grad school and am working on an algorithm to try and model the rate of supernova (type I and II) in our galaxy. I really need to know the following information. 1) Where can I find information on HOW MANY of the different types of stars there are in our...
  50. R

    How did Todd Shriber think he was going to get away with this?

    http://www.cbsnews.com/stories/2006/12/22/politics/main2292806.shtml The correspondence is posted online: http://www.attrition.org/postal/z/033/0871.html
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