Observation data Epoch J2000 Equinox J2000 |
|
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Constellation | Virgo |
Right ascension | 11h 47m 44.3964s[1] |
Declination | +00° 48′ 16″[1] |
Apparent magnitude (V) | 11.13[2] |
Characteristics | |
Spectral type | M4 V[3] |
U−B color index | 2.685[4] |
B−V color index | 1.59[5] |
Variable type | Flare star |
Astrometry | |
Radial velocity (Rv) | -31.0[6][7] km/s |
Proper motion (μ) | RA: 605.66[1] mas/yr Dec.: -1219.32[1] mas/yr |
Parallax (π) | 298.2 ± 1.7[8] mas |
Distance | 10.94 ± 0.06 ly (3.35 ± 0.02 pc) |
Absolute magnitude (MV) | 13.51[2] |
Details | |
Mass | 0.15[9] M☉ |
Radius | 0.21[10] R☉ |
Luminosity | 0.00036[11] L☉ |
Luminosity (bolometric) | 0.0035[12] L☉ |
Surface gravity (log g) | 3.40[9] cgs |
Temperature | 3,180[3] K |
Other designations | |
Database references | |
SIMBAD | data |
Ross 128 is a small star in the equatorial zodiac constellation of Virgo, the virgin. The apparent magnitude of Ross 128 is 11.13,[2] which is much too faint to be seen with the naked eye. Based upon parallax measurements, the distance of this star from Earth is 10.89 light-years (3.34 parsecs), making it the twelfth closest star to the Solar System. It was first cataloged in 1926 by American astronomer Frank Elmore Ross.[13]
This low mass star has a stellar classification of M4 V,[3] which places it among a category of stars known as red dwarfs. It has 15%[9] of the mass of the Sun and 21%[10] of the Sun's radius, but generates energy so slowly that it has only 0.036% of the Sun's visible luminosity.[11] However, most of the energy being radiated by the star is in the infrared band, with the bolometric luminosity being equal to 0.35% of solar.[12] This energy is being radiated from the star's outer atmosphere at an effective temperature of 3,180 K.[3] This gives it the cool orange-red glow of an M-type star.
Ross 128 is an old disk star, which means it has a low abundance of elements other than hydrogen and helium, what astronomers term the star's metallicity, and it orbits near the plane of the Milky Way galaxy.[14] It is classified as an active flare star since it can undergo unpredictable and dramatic increases in luminosity for a period of several minutes.[15] Because of the low rate of flare activity, it is thought to be a magnetically evolved star. That is, there is some evidence that the magnetic braking of the star's stellar wind has lowered the frequency of flares, but not the net yield.[16]
On multiple occasions this star has been examined for the existence of a low stellar mass or brown dwarf companion orbiting at a distance of at least 1 astronomical unit from the primary. However, no companions have yet been discovered.[17][18] The star also lacks a strong excess of infrared radiation. An infrared excess is usually an indicator of a dust ring in orbit around the star.[19][20]
Ross 128 is orbiting through the Milky Way with an orbital eccentricity of 0.122, causing its distance from the Galactic Center to range between 26.8–34.2 kly (8.2–10.5 kpc).[21] This orbit will bring the star closer to the Solar System in the future. The nearest approach will occur in about 71,000 years, when it will come within 6.233 ± 0.085 ly (1.911 ± 0.026 pc).[7]
Distance
Source | Parallax, mas | Distance, pc | Distance, ly | Distance, Pm | Ref. |
---|---|---|---|---|---|
Woolley et al. (1970) | 301±5 | 3.32+0.06 −0.05 |
10.84±0.18 | 102.5±1.7 | [22] |
Gliese & Jahreiß (1991) | 301.1±1.9 | 3.321±0.021 | 10.83±0.07 | 102.5+0.7 −0.6 |
[23] |
van Altena et al. (1995) | 298.2±1.7 | 3.353±0.019 | 10.94±0.06 | 103.5±0.6 | [8] |
Perryman et al. (1997) (Hipparcos) | 299.58±2.20 | 3.338+0.025 −0.024 |
10.89±0.08 | 103±0.8 | [24] |
Perryman et al. (1997) (Tycho) | (absents) | [25] | |||
van Leeuwen (2007) | 298.04±2.30 | 3.355±0.026 | 10.94+0.09 −0.08 |
103.5±0.8 | [26] |
RECONS TOP100 (2012) | 298.14±1.37[note 1] | 3.354±0.015 | 10.94±0.05 | 103.5±0.5 | [27] |
Non-trigonometric distance estimates are marked in italic. The most precise estimate is marked in bold.
See also
References
- ^ a b c d e Perryman, M. A. C. et al. (1997), "The Hipparcos Catalogue", Astronomy & Astrophysics 323: L49–L52, Bibcode:1997A&A...323L..49P
- ^ a b c The One Hundred Nearest Star Systems, Research Consortium on Nearby Stars, 2009-01-01, retrieved 2009-09-03
- ^ a b c d Gautier, Thomas N., III et al., "Far Infrared Properties of M Dwarfs", Bulletin of the American Astronomical Society 36: 1431, Bibcode:2004AAS...205.5503G
- ^ Rufener, F. (October 1976), "Second catalogue of stars measured in the Geneva Observatory photometric system", Astronomy & Astrophysics Supplement Series 26: 275–351, Bibcode:1976A&AS...26..275R
- ^ Warren, W. H., Jr. (1978), "Photoelectric Photometric Catalogue of Homogeneous Means in the UBV System", Observatory (Geneva)
- ^ Gontcharov, G. A. (2006), Pulkovo Compilation of Radial Velocities for 35493 Hipparcos Stars, retrieved 2010-04-18
- ^ a b García-Sánchez, J. et al. (2001), "Stellar encounters with the solar system", Astronomy and Astrophysics 379 (2): 634–659, Bibcode:2001A&A...379..634G, doi:10.1051/0004-6361:20011330
- ^ a b Van Altena W. F., Lee J. T., Hoffleit E. D. (1995). "GCTP 2730". The General Catalogue of Trigonometric Stellar Parallaxes (Fourth ed.). Retrieved 2014-10-20.
- ^ a b c Rodonò, Marcello, "The Atmospheres of M Dwarfs: Observations", The M-Type Stars, Washington: NASA, pp. 409–453
- ^ a b White, Stephen M.; Jackson, Peter D.; Kundu, Mukul R. (December 1989), "A VLA survey of nearby flare stars", Astrophysical Journal Supplement Series 71: 895–904, Bibcode:1989ApJS...71..895W, doi:10.1086/191401
- ^ a b Zombeck, Martin V. (2007), Handbook of Space Astronomy and Astrophysics (Third ed.), Cambridge, UK: Cambridge University Press, p. 109, ISBN 0-521-78242-2
- ^ a b "HIP 57548", NASA Exoplanet Archive, retrieved 2012-03-06
- ^ Ross, Frank E. (1926), "New proper-motion stars, (second list)", Astronomical Journal 36 (856): 124–128, Bibcode:1926AJ.....36..124R, doi:10.1086/104699
- ^ Sánchez, F. (1990), Vazquez, M., ed., New windows to the universe 2, Cambridge University Press, p. 313, ISBN 0-521-38429-X
- ^ Kunkel, W. E. (July 29 – August 4, 1974), "Solar neighborhood flare stars - A review", Variable stars and stellar evolution; Proceedings of the Symposium, Moscow, USSR: D. Reidel Publishing Co, pp. 15–46, Bibcode:1975IAUS...67...15K
- ^ Skumanich, Andrew (1986-10-15), "Some evidence on the evolution of the flare mechanism in dwarf stars", Astrophysical Journal, Part 1 309: 858–863, Bibcode:1986ApJ...309..858S, doi:10.1086/164654
- ^ Hinz, Joannah L. et al. (April 2002), "A Near-Infrared, Wide-Field, Proper-Motion Search for Brown Dwarfs", The Astronomical Journal 123 (4): 2027–2032, arXiv:astro-ph/0201140, Bibcode:2002AJ....123.2027H, doi:10.1086/339555
- ^ Schroeder, Daniel J. et al. (2000), "A Search for Faint Companions to Nearby Stars Using the Wide Field Planetary Camera 2", The Astronomical Journal 119 (2): 906–922, Bibcode:2000AJ....119..906S, doi:10.1086/301227
- ^ Jura, M. et al. (September 2004), "Mid-Infrared Spectra of Dust Debris around Main-Sequence Stars", The Astrophysical Journal Supplement Series 154 (1): 453–457, arXiv:astro-ph/0405632, Bibcode:2004ApJS..154..453J, doi:10.1086/422975
- ^ Gautier, Thomas N., III et al. (September 2007), "Far-Infrared Properties of M Dwarfs", The Astrophysical Journal 667 (1): 527–536, arXiv:0707.0464, Bibcode:2007ApJ...667..527G, doi:10.1086/520667
- ^ Allen, C.; Herrera, M. A. (1998), "The galactic orbits of nearby UV Ceti stars", Revista Mexicana de Astronomia y Astrofisica 34: 37–46, Bibcode:1998RMxAA..34...37A
- ^ Woolley R.; Epps E. A.; Penston M. J.; Pocock S. B. (1970). "Woolley 447". Catalogue of stars within 25 parsecs of the Sun. Retrieved 2014-10-20.
- ^ Gliese, W. and Jahreiß, H. (1991). "Gl 447". Preliminary Version of the Third Catalogue of Nearby Stars. Retrieved 2014-10-20.
- ^ Perryman et al. (1997). "HIP 57548". The Hipparcos and Tycho Catalogues. Retrieved 2014-10-20.
- ^ Perryman et al. (1997). "HIP 57548". The Hipparcos and Tycho Catalogues. Retrieved 2014-10-20.
- ^ van Leeuwen F. (2007). "HIP 57548". Validation of the new Hipparcos reduction. Retrieved 2014-10-20.
- ^ "RECONS TOP100". THE ONE HUNDRED NEAREST STAR SYSTEMS brought to you by RECONS (Research Consortium On Nearby Stars). 2012. Retrieved 2014-10-20.
Notes
- ^ Weighted parallax based on parallaxes from van Altena et al. (1995) and van Leeuwen (2007).
External links
Coordinates: 11h 47m 44.4s, +00° 48′ 16″
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