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Latest Main sequence Stories

88eed3d812fc21259b4bf99d0a94afa91
2008-12-12 12:45:00

Astronomy & Astrophysics is publishing spectroscopic observations with NASA's space-based Far-Ultraviolet Spectroscopic Explorer (FUSE) of the white dwarf KPD 0005+5106. The team of German and American astronomers who present these observations show that this white dwarf is among the hottest stars known so far, with a temperature of 200 000 K at its surface. It is so hot that its photosphere exhibits emission lines in the ultraviolet spectrum, a phenomenon that has never been seen before....

2008-07-11 15:00:09

Almost two months ago my newborn son began his life just as stars go through a life cycle of their own. Stars are formed from within a nebula, a cloud of gas and dust. Over time, hydrogen gas is pulled together by gravity and begins to spin faster and faster until the gas heats up to spark nuclear fusion in the core, and a new star is formed. In the first stages of life, a star fuses hydrogen gas into helium. Ninety percent of stars are in this main sequence stage. The sun, about 4.5...

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2008-06-19 09:44:57

NSF-funded basic research may cause astronomers to re-examine the masses and ages of young stars and star formation theories Two stars, each with the same mass and in orbit around each other, are twins that one would expect to be identical. So astronomers were surprised when they discovered that twin stars in the Orion Nebula, a well-known stellar nursery 1,500 light years away, were not identical at all. In fact, these stars exhibited significant differences in brightness, surface...

1f33dd113b14821be731937964b2616f
2008-05-01 12:29:26

Discovery helps solve riddle of where the carbon white dwarfs come from, and what happens to their hydrogen and helium University of Texas at Austin astronomers Michael H. Montgomery and Kurtis A. Williams, along with graduate student Steven DeGennaro, have predicted and confirmed the existence of a new type of variable star, with the help of the 2.1-meter Otto Struve Telescope at McDonald Observatory. The discovery is announced in today's issue of Astrophysical Journal Letters. This research...

ee380e24a70f7effe91ac92e2f79b6321
2007-11-21 13:00:00

Astronomers may have found another way that stars evolve Astronomers have discovered white dwarf stars with pure carbon atmospheres. These stars possibly evolved in a sequence astronomers didn't know before. They may have evolved from stars that are not quite massive enough to explode as supernovae but are just on the borderline. All but the most massive two or three percent of stars eventually die as white dwarfs rather than explode as supernovae. When a star burns helium, it leaves "ashes"...

cb0bb495b5bd512d25c55fa200c6799d
2007-05-01 09:07:46

Flagstaff, Ariz. - Gyrochronology, a new method for accurately determining the ages of field stars based on their rotational rates, was announced in April by Sydney Barnes, Lowell Observatory astronomer. This fundamental research, "Ages for illustrative field stars using gyrochronology: viability, limitations and errors," is accepted for publication in an upcoming issue of the Astrophysical Journal. "Gyrochronology transforms a rotating star into a clock which is set using the Sun and...

2007-04-18 15:33:38

Stunning simulations that give a multi-dimensional glimpse into the interior of stars show that material bubbling around the convection zone induces a rich spectrum of internal gravity waves in the stable layers above and below. The swirling simulations, which are reminiscent of Van Gogh's star paintings, show the interior of a star during the Asymptotic Giant Branch (AGB) phase, the final stage of a low- and intermediate-mass star's life before it becomes a white dwarf. It is during this...

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2007-04-17 10:45:00

Cambridge, MA - Astronomers have found the lowest mass white dwarf known in our galaxy: a Saturn-sized ball of helium containing only about one-fifth the mass of the Sun. In addition, they have spotted the source of the white dwarf's radical weight-loss plan. An unseen companion, likely another white dwarf, has sucked away much of the tiny white dwarf's material, leaving it a shadow of its former self. "This star is bizarre," said Warren Brown of the Harvard-Smithsonian Center for...

c3af746f9b348d70e2026f70bd1cabdb1
2005-04-18 18:57:14

LANL -- A University of California scientist at Los Alamos National Laboratory working with astronomers from around the world recently validated a computer model that predicts the rebirth and stellar burning and mixing processes of evolved stars. The discovery is a leap forward in our understanding of how stars like the sun evolve through violent outbursts during their evolution. In research published recently in the journal Science, Laboratory astrophysicist Falk Herwig and his colleagues...

3cd8f80eae67cbb08d5169fc0de3ef541
2005-04-18 18:45:00

A primitive star with extremely low iron content has been discovered by an international research team from Sweden, Japan, Germany, USA, Australia and Great Britain. This indicates the original composition of the gas from which the star formed had low iron content. The results are published in Nature online this week. In 2001, the giant star HE0107-5240 was discovered among a large number of stars examined as part of the Hamburg/ESO* survey. Detailed studies revealed that the star had by far...


Latest Main sequence Reference Libraries

7_4b235c0bfbfc8504a41844f9c48ad8962
2004-10-19 04:45:43

Hertzsprung-Russell Diagram -- In stellar astronomy, the Hertzsprung-Russell diagram (H-R diagram) shows the relation between the absolute magnitude and the spectral types of stars. It was invented around 1910 by Ejnar Hertzsprung and Henry Norris Russell. There are two equivalent forms. One is the observer's form which plots the color of the star on one axis and the absolute magnitude on the other axis. The theoretician's form plots the temperature of the star on one axis and the...

6_dac4e7d6b8fb5cf3a1458d796b90d7a92
2004-10-19 04:45:42

Stellar Evolution -- Stellar evolution is the process of formation, life, and death of stars. It is one of the major topics of cosmogony. Star Birth and Life A star starts out as an enormous cloud of gas and dust many light-years across. Star formation begins when the cloud begins to condense under its own gravity. The processes that initiate this contraction are not fully understood. The cloud fragments fuse into stellar mass clouds known as protostars. Protostars do not emit...

6_d67b2db586c7facec8388b5df78e57912
2004-10-19 04:45:42

Star -- A star is a self-gravitating sphere of plasma in hydrostatic equilibrium that generates energy in its interior through the process of nuclear fusion. Energy from this process radiates into space as electromagnetic radiation and neutrinos. Star formation and evolution As learned by star formation astronomers, stars are born in molecular clouds, regions of higher density of matter, and form by gravitational instability inside those clouds. High mass stars illuminate powerfully...

6_9182d2d493640e91b36f6c6769af79e62
2004-10-19 04:45:42

Red Dwarf -- A red dwarf is a small star on the main sequence, either late K or M spectral type. They have a diameter and mass of less than one-third that of the Sun (down to 0.08 solar masses, which are Brown dwarves) and a surface temperature of less than 3,500 K. They emit little light, sometimes as little as 1/10,000th that of the sun. Due to the slow rate at which they burn hydrogen red dwarves have a enormous lifespan, estimates range from a tens of billions up to trillions of...

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Word of the Day
omadhaun
  • A fool; a simpleton: a term of abuse common in Ireland and to a less extent in the Gaelic-speaking parts of Scotland.
This word is partly Irish in origin.