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.
Schlaufman, K. C. & Winn, J. N. Evidence for the tidal destruction of hot Jupiters by
subgiant stars.
It appears to be
a subgiant star that is evolving off the main sequence, as it begins to fuse the increasing amounts of helium «ash» mixed with hydrogen at its core.
Altair has the New Suspected Variable designation NSV 24910 and is unusually bright for its spectral type and so may be becoming
a subgiant star that is beginning to evolve off the main sequence, as it begins to fuse the increasing amounts of helium «ash» mixed with hydrogen at its core.
According to Emeritus Professor Jim Kaler, Beta Hydri entered the main sequence a dwarf star at the cooler end of class F (probably around spectral class F8) but now appears to be
a subgiant star that is evolving off the main sequence, as it begins to fuse increasing amounts of helium «ash» mixed with hydrogen at its core.
As
a subgiant star subject to pulsations which affect careful measurements of variations in radial velocity caused by the gravitational pull of substellar companions, astronomers would find it very difficult to detect any Earth - type planet around Beta Hydri using present methods.
As
a subgiant star subject to pulsations which affect careful measurements of radial velocity, astronomers would find it very difficult to detect any Earth - type planet arond this star using present methods.
The primary component in the system is a spectroscopic binary with the stellar classification of B2 IV, matching the spectrum of a blue - white
subgiant star.
Not exact matches
Retired A
stars and their companions: exoplanets orbiting three intermediate - mass
subgiants.
Evolutionary analysis of the host
star suggests that KELT - 10b is unlikely to survive beyond the current
subgiant phase, due to a concomitant in - spiral of the planet over the next $ \ sim $ 1 Gyr.
© Torben Krogh & Mogens Winther, (Amtsgymnasiet and EUC Syd Gallery, student photo used with permission) HD 181433 is an orange - red
star (similar to Epsilon Eridani at left center of meteor) that may have already evolved into a
subgiant, but is probably not yet a giant,
star.
HD 181433 may be a
subgiant rather than a main - sequence, orange - red dwarf
star (Sousa et al, 2008; and ARICNS), but is probably not an giant,
star (SIMBAD) of spectral and luminosity type K3 - 5 V - III.
According to Professor Jim Kaler at the University of Illinois» Department of Astronomy, Rana started life as a main sequence F8 dwarf (somewhat hotter and brighter than Sol with slightly greater mass) around 7.5 billion years ago, but core hydrogen fusion has ceased causing the
star to expand and cool as an active
subgiant before becoming much brighter and larger «as a true giant
star» through core helium fusion.
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.
Achernar is a blue - white main sequence
star of spectral and luminosity type B3 Vpe (Hiltner et al, 1969), that previously had been classed as bright as a
subgiant.
Tau Boötis A is a yellowish main sequence dwarf
star of spectral and luminosity type F7 V, although it has also been classified as a F6 IV
subgiant.
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 below).
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.
Star A is probably a yellow - orange
subgiant of spectral and luminosity type G0 IV (NASA
Stars and Exoplanet Database; and Garrison and Beattie, 1998).
A comparison with stellar properties in the planet - candidate catalog by Batalha et al. shows that radii for
subgiants and giants obtained from spectroscopic follow - up are systematically too low by up to a factor of 1.5, while the properties for unevolved
stars are in good agreement.
Star A is probably a yellow - orange
subgiant of spectral and luminosity type G0 IV).
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.
Life on an Earth - like planet, however, may have developed closer to the
star before it evolved and began heating up out of the main sequence into a
subgiant, thereby shifting its habitable zone outwards away from the
star.
The system is composed of a blue - white giant with the stellar classification of B9III - IV and a visual magnitude of 5.33, a white
subgiant belonging to the stellar class A0IVMn with an apparent magnitude of 5.63, and a
star with a magnitude of 8.5 separated from the second component by 37.7 arc seconds.