Sentences with phrase «main sequence stars in»
Main sequence stars in this region experience only small changes in magnitude and so this variation is difficult to detect.
http://www.newworldencyclopedia.org/ Not exact matches
Estimates of the odds of a planet in general vary; some studies suggest sunlike stars have about a one in 10 chance of hosting an Earth - like planet, for example, whereas others say it's possible nearly every main - sequence star has at least one planet of some type orbiting it.
The essence is that the stars are on the main sequence during most of their life time and «burn» hydrogen in this time («burning» is an often used word here; in reality it's not a chemical reaction, but a nuclear reaction: hydrogen nuclei are fused to helium nuclei).
In the original work by Brown, slightly different classes of false positives were used: MPU (main - sequence star with a giant planet); MSU (undiluted binaries); and the two types of diluted binaries, MSDF (an eclipsing binary + a third non-related star) and MSDT (triple systems).
Superflares have also been observed in a group of dim main - sequence, reddish M dwarfs known as flare stars.
Gazing at a fixed spot in the constellation Cygnus, the Kepler telescope continually monitored 100,000 main - sequence stars for planets.
The internal structures of giant planets are much less well known than those of main - sequence stars because of uncertainties in the equation of state of degenerate gas, the composition (typically non-solar), the interaction with the magnetic field and, in the upper layers, the relative magnitudes of internal heat and energy deposited from the sun.
The ordinary hydrogen - burning dwarf stars like the Sun are found in a band running from top - left to bottom - right called the Main Sequence.
As the stars evolve, they adjust to the increase in the helium - to - hydrogen ratio in their cores and gradually move away from the zero - age main sequence.
Theoretical calculations suggest that, as the star evolves from the main sequence, the hydrogen - helium core gradually increases in mass but shrinks in size as more and more helium ash is fed in through the outer hydrogen - burning shell.
Although we do not detect the predicted 2 - 5 minute transit timing... ▽ More K2 - 138 is a moderately bright (V = 12.2, K = 10.3) main sequence K - star observed in Campaign 12 of the NASA K2 mission.
Star A is a main sequence dwarf star of spectral and luminosity type F7 - 8 V (Wittenmyer et al, 2006, page 178; Bonavita and Desidera, 2007, HD 16895 in Table 8; and NASA Stars and Exoplanet Database) but has been classed as yellow as F9 (Baize and Petit, 1989, page Star A is a main sequence dwarf star of spectral and luminosity type F7 - 8 V (Wittenmyer et al, 2006, page 178; Bonavita and Desidera, 2007, HD 16895 in Table 8; and NASA Stars and Exoplanet Database) but has been classed as yellow as F9 (Baize and Petit, 1989, page star of spectral and luminosity type F7 - 8 V (Wittenmyer et al, 2006, page 178; Bonavita and Desidera, 2007, HD 16895 in Table 8; and NASA Stars and Exoplanet Database) but has been classed as yellow as F9 (Baize and Petit, 1989, page 505.
The early evolution of high - mass stars is similar; the only difference is that their faster overall evolution may allow them to reach the main sequence while they are still enshrouded in the cocoon of gas and dust from which they formed.
Known as subdwarfs, these stars are also fusing hydrogen in their core and so they mark the lower edge of the main sequence's fuzziness resulting from chemical composition.
In high mass main sequence stars, the opacity is dominated by electron scattering, which is nearly constant with increasing temperature.
Other factors that broaden the main sequence band on the HR diagram include uncertainty in the distance to stars and the presence of unresolved binary stars that can alter the observed stellar parameters.
The current position where stars in this cluster are leaving the main sequence is known as the turn - off point.
This effect results in a broadening of the main sequence band because stars are observed at random stages in their lifetime.
In addition to variations in chemical composition — both because of the initial abundances and the star's evolutionary status, [34] interaction with a close companion, [35] rapid rotation, [36] or a magnetic field can also change a main sequence star's position slightly on the HR diagram, to name just a few factorIn addition to variations in chemical composition — both because of the initial abundances and the star's evolutionary status, [34] interaction with a close companion, [35] rapid rotation, [36] or a magnetic field can also change a main sequence star's position slightly on the HR diagram, to name just a few factorin chemical composition — both because of the initial abundances and the star's evolutionary status, [34] interaction with a close companion, [35] rapid rotation, [36] or a magnetic field can also change a main sequence star's position slightly on the HR diagram, to name just a few factors.
In general, the more massive the star, the shorter its time on the main sequence.
The strip intersects the upper part of the main sequence in the region of class A and F stars, which are between one and two solar masses.
Our planet orbits in the habitable zone (HZ) of a G - type main - sequence star that we call the Sun.
Six hundred and twenty light - years from Earth, in the constellation Cygnus, a bright, young, Type - A, blue, main - sequence star designated KELT - 9 burns brightly.
We present new high - contrast data obtained during the commissioning of the SPHERE instrument at... ▽ More GJ758 B is a brown dwarf companion to a nearby (15.76 pc) solar - type, metal - rich (M / H = +0.2 dex) main - sequence star (G9V) that was discovered with Subaru / HiCIAO in 2009.
Abstract: GJ758 B is a brown dwarf companion to a nearby (15.76 pc) solar - type, metal - rich (M / H = +0.2 dex) main - sequence star (G9V) that was discovered with Subaru / HiCIAO in 2009.
In 1995, University of Geneva astronomers Michel Mayor and Didier Queloz announced the discovery of the first planet outside our solar system, a Jupiterlike giant orbiting around a «main sequence» star similar to our sun, 51 Pegasi [source: Mayor and Queloz].
Lambda Serpentis is a main sequence dwarf star of spectral and luminosity type G0 V, but it is listed as a possible subgiant in some catalogues.
In about five billion years, our own Sun will make the transition from a main - sequence yellow dwarf star, to a red giant, with dramatic implications for Earth.
We aren't yet in a position to say, but the question is intriguing because some models suggest that the number of brown dwarfs is comparable to the number of low - mass main sequence stars.
Moreover, the star's discovery suggest that even relatively low - mass Population III stars could have formed and survived until today, still shining faintly below easy detectability as main sequence dwarf stars in distant reaches of the galactic halo.
In March 2005, astronomers seeking ancient stars announced the discovery of HE 1327 - 2326, a subgiant or main - sequence dwarf star with extremely low metallicity — an iron abundance -LRB-[Fe / H] = -5.4 + / - 0.2) that is only about 1/250, 000 th of Sol's and a factor of two lower than that of giant star HE 0107 - 5240 (which is discussed in detail belowIn March 2005, astronomers seeking ancient stars announced the discovery of HE 1327 - 2326, a subgiant or main - sequence dwarf star with extremely low metallicity — an iron abundance -LRB-[Fe / H] = -5.4 + / - 0.2) that is only about 1/250, 000 th of Sol's and a factor of two lower than that of giant star HE 0107 - 5240 (which is discussed in detail belowin detail below).
This star is a white - yellow main sequence dwarf star of spectral and luminosity type F6 V, with almost 1.3 times Sol's mass (NASA Star and Exoplanet Database; and David F. Gray, 1992), 1.2 5o 1.3 times its diameter (von Belle and von Braun, 2009, HD 30652 in Table 4, page 7; Perrin and Karoji, 1987; NASA Star and Exoplanet Database; and Kenneth R. Lang, 1980), and over 2.6 times of its bolometric luminosity (NASA Star and Exoplanet Database; and Kenneth R. Lang, 19star is a white - yellow main sequence dwarf star of spectral and luminosity type F6 V, with almost 1.3 times Sol's mass (NASA Star and Exoplanet Database; and David F. Gray, 1992), 1.2 5o 1.3 times its diameter (von Belle and von Braun, 2009, HD 30652 in Table 4, page 7; Perrin and Karoji, 1987; NASA Star and Exoplanet Database; and Kenneth R. Lang, 1980), and over 2.6 times of its bolometric luminosity (NASA Star and Exoplanet Database; and Kenneth R. Lang, 19star of spectral and luminosity type F6 V, with almost 1.3 times Sol's mass (NASA Star and Exoplanet Database; and David F. Gray, 1992), 1.2 5o 1.3 times its diameter (von Belle and von Braun, 2009, HD 30652 in Table 4, page 7; Perrin and Karoji, 1987; NASA Star and Exoplanet Database; and Kenneth R. Lang, 1980), and over 2.6 times of its bolometric luminosity (NASA Star and Exoplanet Database; and Kenneth R. Lang, 19Star and Exoplanet Database; and David F. Gray, 1992), 1.2 5o 1.3 times its diameter (von Belle and von Braun, 2009, HD 30652 in Table 4, page 7; Perrin and Karoji, 1987; NASA Star and Exoplanet Database; and Kenneth R. Lang, 1980), and over 2.6 times of its bolometric luminosity (NASA Star and Exoplanet Database; and Kenneth R. Lang, 19Star and Exoplanet Database; and Kenneth R. Lang, 1980), and over 2.6 times of its bolometric luminosity (NASA Star and Exoplanet Database; and Kenneth R. Lang, 19Star and Exoplanet Database; and Kenneth R. Lang, 1980).
Because K2 - 39b has a short orbital period, its existence makes it seem unlikely that tidal destruction is wholly responsible for the differences in planet populations around subgiant and main - sequence stars.
About 1 in 160 (0.625 %) of the main - sequence stars in the solar neighborhood are A-type stars.
[7] Like the other stars in the group, it is a main sequence star not unlike the Sun, although somewhat hotter, brighter and larger.
Given the short life of massive B - type stars, it is highly unlikely that an Earth - type planet with advanced multi-cellular life could have developed in Gacrux's water zone before it left the main sequence.
The companion star frequency of low - mass stars is comparable to that of main - sequence M - dwarfs, less than half that of solar - type main - sequence stars, and 3.5 to 5 times lower than in the Taurus - Auriga and Scorpius - Centaurus star - forming regions.
Abstract: Photometric observations made by the NASA Kepler Mission have led to a dramatic increase in the number of main - sequence and subgiant stars with detected solar - like oscillations.
Main - sequence stars vary in surface temperature from approximately 2,000 to 50,000 K, whereas more - evolved stars can have temperatures above 100,000 K. Physically, the classes indicate the temperature of the star's atmosphere and are normally listed from hottest to coldest.
They make up about 12 % of the main - sequence stars in the solar neighborhood.
Massive yet non-supergiant entities known as «Be stars» are main - sequence stars that notably have, or had at some time, one or more Balmer lines in emission, with the hydrogen - related electromagnetic radiation series projected out by the stars being of particular interest.
Class G main - sequence stars make up about 7.5 %, nearly one in thirteen, of the main - sequence stars in the solar neighborhood.
This observation result was published Silverman et al. «A higher efficiency of converting gas to stars pushes galaxies at z ~ 1.6 well - above the star - forming main sequence» in the Astrophysical Journal Letters, issued in October 2015.
Marginal cases are allowed; for example, a star may be either a supergiant or a bright giant, or may be in between the subgiant and main - sequence classifications.
As a star that has evolved out of the «main sequence,» Arcturus has fully shifted from the fusion of hydrogen to helium in at its core to the fusion of helium to carbon and oxygen, with trace activity of other nuclear processes.
Previously, such large flares had not been observed in Sol - type main sequence stars, although they are common in a group of dim main - sequence, reddish M dwarfs known as flare stars.
About 76 % of the main - sequence stars in the solar neighborhood are class M stars.
After we have calculated the S indices for the 5,648 main - sequence stars based on the LAMOST spectra with signal - to - noise ratios higher than 10 in the blue part of the spectrum, including the subset of 48 superflare stars, it is possible to calculate the flare rates.
Almost all the soft X-ray sources have been identified in NIR and their spectral types are consistent with main - sequence stars, suggesting most of them are nearby X-ray active stars.
We aim to determine the level of near - infrared exozodiacal dust emission around a sample of 42 nearby main sequence stars with... ▽ More (Abridged) Dust is expected to be ubiquitous in extrasolar planetary systems owing to the dynamical activity of minor bodies.