Ross 458

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Template:Short description

Ross 458
File:DT Virginis.jpg
Image of Ross 458 with the legacy surveys. The companion is the red object marked with an crosshair in the lower right.
Observation data
Epoch J2000      Equinox J2000
Constellation Virgo[1]
Right ascension Template:RA[2]
Declination Template:DEC[2]
Apparent magnitude (V) 9.79[3]
Characteristics
Evolutionary stage Main sequence
Spectral type M0.5 + M7.0[4]
U−B Template:Engvar 1.12[3]
B−V Template:Engvar 1.44[3]
Astrometry
Radial velocity (Rv)Script error: No such module "val".[2] km/s
Proper motion (μ) RA: Script error: No such module "val". mas/yr[2]
Dec.: Script error: No such module "val". mas/yr[2]
Parallax (π)86.9010±0.1170 mas[2]
DistanceTemplate:Rnd ± Template:Rnd ly
(Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)+9.47[1]
Orbit[5]
Period (P)13.63±0.03 yr
Semi-major axis (a)Script error: No such module "val".
Eccentricity (e)0.245±0.001
Inclination (i)130.3±0.3°
Longitude of the node (Ω)56.25±0.17°
Periastron epoch (T)2007.67±0.02
Argument of periastron (ω)
(secondary)		157.5±0.6°
Details
Primary (A)
Mass0.553±0.007[5] Template:Solar mass
RadiusScript error: No such module "val".[6]
0.368±0.031[7] Template:Solar radius
LuminosityScript error: No such module "val".[7] Template:Solar luminosity
Temperature3,484±50[6] K
Metallicity [Fe/H]0.09±0.10[7] dex
RotationScript error: No such module "val".[8]
Rotational velocity (v sin i)9.6±0.9[9] km/s
Age400–800[4] Myr
Secondary (B)
MassScript error: No such module "val".[10] MJup
Metallicity [Fe/H]{{{metal_fe2}}} dex
C
MassScript error: No such module "val".[11] MJup
RadiusScript error: No such module "val".[11] RJup
LuminosityScript error: No such module "val".[11] Template:Solar luminosity
Surface gravity (log g)Script error: No such module "val".[11] cgs
TemperatureScript error: No such module "val".[11] K
Metallicity [Fe/H]{{{metal_fe2}}} dex
Other designations
Template:Odlist[12]
Database references
SIMBADdata
Exoplanet Archivedata
ARICNSdata

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Ross 458, also referred to as DT Virginis, is a binary star system in the constellation of Virgo. It has an apparent visual magnitude of 9.79[3] and is located at a distance of 37.6 light-years from the Sun. Both of the stars are low-mass red dwarfs with at least one of them being a flare star. This binary system has a circumbinary sub-stellar companion.

Description

File:DTVirLightCurve.png
A light curve for Ross 458. The main plot, adapted from Shakhovskaya (1969),[13] shows the intensity of a flare relative to the star's quiescent intensity. The inset plot, adapted from Kiraga (2012),[14] shows the periodic variation.

This star was mentioned as a suspected variable by M. Petit in 1957.[15] In 1960, O. J. Eggen classified it as a member of the Hyades moving group based on the system's space motion;[16] it is now considered a likely member of the Carina Near Moving Group.[6] Two flares were reported from this star in 1969 by N. I. Shakhovskaya, confirming it as a flare star.[13] It was identified as an astrometric binary in 1994 by W. D. Heintz, who found a period of 14.5 years.[5] The pair were resolved using adaptive optics in 1999.[5] Early mass estimates placed the companion near the substellar limit, and it was initially proposed as a brown dwarf[17] but is now considered late-type red dwarf.[4]

The primary member, component A, is an M-type main-sequence star with a stellar classification of M0.5.[4] It is young, magnetically very active star with a high rate of rotation[17] and strong Hα emission.[4] The star experiences star spots that cover 10–15% of the surface[3] It is smaller and less massive than the Sun. The star is radiating just 4.4%[7] of the luminosity of the Sun from its photosphere at an effective temperature of 3,484 K.[6]

Planetary system

A distant sub-stellar companion to the binary star system was discovered in 2010 as part of a deep infrared sky survey. This is most likely a T8 spectral type brown dwarf with an estimated rotation period of Script error: No such module "val".. The object varies slightly in brightness, which may be due to patchy clouds.[4] The companion lacks detectable oxygen in the atmosphere, implying its formation from sequestrated source or peculiar atmospheric chemistry.[18]

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See also

References

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  6. ↑ a b c d Script error: No such module "Citation/CS1".
  7. ↑ a b c d Script error: No such module "Citation/CS1".
  8. ↑ Script error: No such module "Citation/CS1".
  9. ↑ Script error: No such module "Citation/CS1".
  10. ↑ Script error: No such module "Citation/CS1".
  11. ↑ a b c d e Script error: No such module "Citation/CS1".
  12. ↑ Template:Cite simbad
  13. ↑ a b Script error: No such module "Citation/CS1".
  14. ↑ Script error: No such module "Citation/CS1".
  15. ↑ Script error: No such module "Citation/CS1".
  16. ↑ Script error: No such module "Citation/CS1".
  17. ↑ a b Script error: No such module "Citation/CS1".
  18. ↑ Script error: No such module "citation/CS1".

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External links

Template:Stars of Virgo

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