Jump to content

Wolf 359

Coordinates: Sky map 10h 56m 28.99s, +07° 00′ 52″
This is a good article. Click here for more information.
From Wikipedia, the free encyclopedia
(Redirected from CN Leo)
Wolf 359

Wolf 359 is the orange-hued star located just above the center of this 2009 astrophotograph.
Observation data
Epoch J2000      Equinox J2000
Constellation Leo
Right ascension 10h 56m 28.92087s[1]
Declination +07° 00′ 53.0033″[1]
Apparent magnitude (V) 13.507[2]
Characteristics
Spectral type M6V[3]
Apparent magnitude (J) 7.1[4]
Apparent magnitude (K) 6.1[4]
U−B color index +1.165[2]
B−V color index +2.034[2]
Variable type UV Ceti[5]
Astrometry
Radial velocity (Rv)+19±1[6] km/s
Proper motion (μ) RA: −3,866.338 mas/yr[1]
Dec.: −2,699.215 mas/yr[1]
Parallax (π)415.1794 ± 0.0684 mas[1]
Distance7.856 ± 0.001 ly
(2.4086 ± 0.0004 pc)
Absolute magnitude (MV)16.614[7]
Details
Mass0.110±0.003[8] M
Radius0.144±0.004[8] R
Luminosity0.00106 ± 0.00002[8] L
Habitable zone inner limit0.024[9] AU
Habitable zone outer limit0.052[9] AU
Surface gravity (log g)5.5[10] cgs
Temperature2,749+44
−41
[8] K
Metallicity [Fe/H]+0.25[11] dex
Rotation2.704±0.003 d[12]
Rotational velocity (v sin i)2.9±0.8[13] km/s
Age0.1-1.5[14] Gyr
Other designations
CN Leonis, CN Leo, GJ 406, G 045-020, LTT 12923, LFT 750, LHS 36, GCTP 2553[15]
Database references
SIMBADdata
Wolf 359 is located in the constellation Leo.
Wolf 359 is located in the constellation Leo.
Wolf 359
Wolf 359 is shown near the ecliptic in the southern region of Leo.

Wolf 359 is a red dwarf star located in the constellation Leo, near the ecliptic. At a distance of 7.86 light-years (2.41 parsecs) from Earth, it has an apparent magnitude of 13.54 and can only be seen with a large telescope. Wolf 359 is one of the nearest stars to the Sun with only the Alpha Centauri system (including Proxima Centauri), Barnard's Star, and the brown dwarfs Luhman 16 (WISE 1049-5319) and WISE 0855−0714 known to be closer. Its proximity to Earth has led to its mention in several works of fiction.[16]

Wolf 359 is one of the faintest and least-massive nearby stars known. At the light-emitting layer called the photosphere, it has a temperature of ~2,800 K, low enough for chemical compounds to form and survive. The absorption lines of compounds such as water and titanium(II) oxide have been observed in its spectrum.[17] The star's surface has a magnetic field hundreds of times as strong as that of the Sun, generated by its thorough internal convection. As a result of this significant magnetic activity, Wolf 359 is a flare star that can undergo sudden and great increases in luminosity, which can persist for several minutes. These flares emit strong bursts of X-ray and gamma ray radiation that have been observed by space telescopes. It is a relatively young star with an estimated age of less than a billion years. No planetary companions for Wolf 359 have been confirmed so far, though there is one unverified candidate, and as yet no debris disks have been found.[14]

Observation history and name

[edit]

Wolf 359 first came to the attention of astronomers because of its relatively high rate of transverse motion against the background, also known as the proper motion. A high rate of proper motion can indicate that the star is located nearby, as closer stars can achieve the same rate of angular change with a lower relative speed. The proper motion of Wolf 359 was first measured in 1917 by German astronomer Max Wolf, aided by astrophotography. In 1919 he published a catalogue of over one thousand stars with high proper motions, including this one, that are still identified by his name.[18] He listed this star as entry number 359, and the star has since been referred to as Wolf 359, in reference to Max Wolf's work.[19]

The first parallax measurement of Wolf 359 was reported in 1928 from the Mount Wilson Observatory, yielding an annual shift in the star's position of 0.407 ± 0.009 arcseconds. From this position change, and the known size of the Earth's orbit, the distance to the star could be estimated. It was the faintest and least-massive star known until the discovery of VB 10 in 1944.[20][21] The infrared magnitude of the star was measured in 1957.[22] In 1969, a brief flare in the luminosity of Wolf 359 was observed, linking it to a class of variable stars known as flare stars.[23]

Properties

[edit]
The position of Wolf 359 on a radar map among all stellar objects or stellar systems within 9 light years (ly) from the map's center, the Sun (Sol). The diamond-shapes are their positions entered according to right ascension in hours angle (indicated at the edge of the map's reference disc), and according to their declination. The second mark shows each's distance from Sol, with the concentric circles indicating the distance in steps of one ly.

Wolf 359 has a stellar classification of M6,[3] although various sources list a spectral class of M5.5,[24] M6.5[25] or M8.[26] Most M-type stars are red dwarfs: they are visually red because the energy emission of such stars reaches a peak in the red and infrared parts of the spectrum.[27] Wolf 359 has a very low luminosity, emitting about 0.1% of the Sun's power.[28][8] If it were moved to the location of the Sun, it would appear ten times as bright as the full Moon.[29]

At an estimated 11% of the Sun's mass, Wolf 359 is just above the lower limit at which a star's core can undergo hydrogen fusion through the proton–proton chain reaction: ~8% of the solar mass.[30] (Substellar objects below this limit are known as brown dwarfs.) The radius of Wolf 359 is an estimated 14.4% that of the Sun,[8] or about 100,200 km.[31] For comparison, the equatorial radius of the planet Jupiter is 71,490 km, making the star a mere 40% wider than the planet.[32]

The entire star undergoes convection, whereby the energy generated at the core is transported toward the surface by the convective motion of stellar plasma, rather than through electromagnetic radiation. This constant circulation redistributes throughout the star any excess accumulation of helium in the core generated by stellar nucleosynthesis.[33] This process allows Wolf 359 to remain on the main sequence as a hydrogen fusing star for proportionately longer than one such as the Sun, for which helium steadily accumulates in the core and is not diluted. In conjunction with a much lower rate of hydrogen consumption due to its low mass and core temperature, Wolf 359 is expected to remain a main sequence star for about eight trillion years before finally exhausting its hydrogen supply and ending up as a helium white dwarf.[34]

A search of this star by the Hubble Space Telescope revealed no stellar companions.[35] No excess infrared emission has been detected, which may indicate the lack of a debris disk around it.[36][37]

Outer atmosphere

[edit]

The outer, light-emitting layer of a star is known as the photosphere. Estimates of the photospheric temperature of Wolf 359 range from 2,500 K to 2,900 K,[38] which is sufficiently cool for equilibrium chemistry to occur. The resulting chemical compounds survive long enough to be observed through their spectral lines.[39] Numerous molecular bands appear in the spectrum of Wolf 359, including those of carbon monoxide (CO),[40] iron hydride (FeH), chromium hydride (CrH), water (H2O),[17] magnesium hydride (MgH), vanadium(II) oxide (VO),[28] titanium(II) oxide (TiO), and possibly the molecule CaOH.[41] Since there are no lines of lithium in the spectrum, this element must have already been consumed by fusion in the core. This indicates that the star must be at least 100 million years old.[28]

Beyond the photosphere lies a nebulous, high temperature region known as the stellar corona. In 2001, Wolf 359 became the first star other than the Sun to have the spectrum of its corona observed by a ground-based telescope. The spectrum showed emission lines of Fe XIII, which is heavily ionized iron that has been stripped of twelve of its twenty-six electrons.[42] The strength of this line can vary over a time period of several hours, which may be evidence of microflare heating.[28]

A blue band light curve for a flare of CN Leonis, adapted from Liefke et al. (2007)[43]

Wolf 359 is classified as a UV Ceti-type flare star,[5] a category of stars that undergo brief, dramatic increases in luminosity due to intense magnetic field activity in their photospheres. Its variable star designation is CN Leonis. Wolf 359 has a relatively high flare rate. Observations with the Hubble Space Telescope detected 32 flare events within a two-hour period, with energies of 1027 ergs (1020 joules) and higher.[26] The mean magnetic field strength at the surface of the star is around 2.2 kG (0.22 teslas), but this value varies significantly on time scales as short as six hours.[24] In comparison, the magnetic field of the Sun averages a strength of 1 gauss (100 μT), although it can reach as high as 3 kG (0.3 T) in active sunspot regions.[44] During periods of flare activity, Wolf 359 has been observed to emit X-rays and gamma rays.[45][46]

Motion

[edit]
Distances of the nearest stars from 20,000 years ago to 80,000 years in the future. Wolf 359 is not displayed, but it is currently at a distance of 7.9 ly and increasing, with a past minimum of 7.3 ly around 13,850 years ago.

The rotation of a star causes a Doppler shift of its spectrum, generally resulting in a broadening of the absorption lines in its spectrum, with the lines increasing in width with higher rotational speeds. However, only the rotational velocity's component in the direction of the observer can be measured by this method, and the resulting data imposes only a lower limit on the star's rotational speed. This projected rotational velocity of Wolf 359 at its equator is less than 3 km/s, below the threshold of detection with spectral line broadening.[6] This low rate of rotation may have been caused by the loss of angular momentum through its stellar wind, which increases greatly during periods of flare activity. Roughly speaking, the spin-down timescale of a star of spectral class M6 is somewhat long, at ~10 billion years, as fully convective stars lose their rotational speeds more slowly than others.[47] However, evolutionary models suggest that Wolf 359 is a relatively young star with an age of less than a billion years.[28]

Wolf 359's proper motion is 4.696 arcseconds per year, and moving away from the Sun at a velocity of ~19 km/s.[6][48] When translated into the galactic coordinate system, the motion corresponds to a space velocity of (U, V, W) = (−26, −44, −18) km/s.[49] This space velocity implies that Wolf 359 belongs to the population of old-disk stars. It follows an orbit through the Milky Way that will bring it as close as 20.5 kly (6.3 kpc) and as distant as 28 kly (8.6 kpc) from the Galactic Center. The predicted galactic orbit has an eccentricity of 0.156, and the star can travel as far as 444 light-years (136 pc) away from the galactic plane.[50] The closest stellar neighbor to Wolf 359 is the red dwarf Ross 128, at 3.79 ly (1.16 pc).[51] Approximately 13,850 years before the present day, Wolf 359 attained its minimal separation of about 7.35 ly (2.25 pc) from the Sun, and has been receding away ever since.[52]

Search for planets

[edit]

Radial velocity measurements of the star in 2011 using the Near Infrared Spectrometer (NIRSPEC) instrument at the Keck II observatory did not reveal any variations that might otherwise indicate the presence of an orbiting companion. This instrumentation is sensitive enough to detect the gravitational perturbations of massive, short period companions with the mass of Neptune or greater.[53]

In June 2019, an international team of astronomers led by Mikko Tuomi from the University of Hertfordshire, UK, submitted a preprint with the results of the first reported detection of two candidate exoplanets orbiting Wolf 359 using the radial velocity method from observations with HARPS in Chile and HIRES in Hawaii.[54] If these planets were confirmed, the setup of the system would be similar to but more extreme than that of the nearby red dwarf Proxima Centauri, with both having a close-in low-mass planet and a farther out higher-mass planet. The theorized and later ruled-out inner planet, Wolf 359 c, would receive per unit area about forty times as much radiative energy as compared to Earth, making it unlikely to be a habitable planet. The as yet unconfimed Wolf 359 b, in contrast, is classified as a cool super-Neptune, receiving roughly a third to a quarter of the energy per unit area as Neptune does from the Sun.[54]

Further observations from the CARMENES survey have found that the radial velocity signal corresponding to the inner planet candidate Wolf 359 c is a false positive, resulting from the rotation of the star rather than a planetary companion.[13][55] A 2023 follow-up study using MAROON-X, CARMENES, HARPS, and HIRES radial velocity data as well as imaging data was unable to either confirm or refute the presence of Wolf 359 b. The same study ruled out the existence of any brown dwarfs or massive gas giant companions within 10 AU of the star, planets more than half the mass of Jupiter within 1 AU, and planets more massive than Uranus within 0.1 AU.[14]

The Wolf 359 planetary system
Companion
(in order from star)
Mass Semimajor axis
(AU)
Orbital period
(days)
Eccentricity Inclination Radius
b (unconfirmed) ≥43.9+29.5
−23.9
M🜨
1.845+0.289
−0.258
2,938±436 0.04+0.27
−0.04

See also

[edit]

References

[edit]
  1. ^ a b c d Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  2. ^ a b c Landolt, Arlo U. (May 2009). "UBVRI photometric standard stars around the celestial equator: Updates and Additions". The Astronomical Journal. 137 (5): 4186–4269. arXiv:0904.0638. Bibcode:2009AJ....137.4186L. doi:10.1088/0004-6256/137/5/4186. S2CID 118627330. See table II.
  3. ^ a b Henry, Todd J.; et al. (October 1994). "The solar neighborhood, 1: Standard spectral types (K5-M8) for northern dwarfs within eight parsecs". The Astronomical Journal. 108 (4): 1437–1444. Bibcode:1994AJ....108.1437H. doi:10.1086/117167.
  4. ^ a b Cutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E.; Fowler, John W.; Gizis, John E.; Howard, Elizabeth V.; Huchra, John P.; Jarrett, Thomas H.; Kopan, Eugene L.; Kirkpatrick, J. Davy; Light, Robert M.; Marsh, Kenneth A.; McCallon, Howard L.; Schneider, Stephen E.; Stiening, Rae; Sykes, Matthew J.; Weinberg, Martin D.; Wheaton, William A.; Wheelock, Sherry L.; Zacarias, N. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". CDS/ADC Collection of Electronic Catalogues. 2246: II/246. Bibcode:2003yCat.2246....0C.
  5. ^ a b Gershberg, R. E.; et al. (1983). "Characteristics of activity energetics of the UV Cet-type flare stars". Astrophysics and Space Science. 95 (2): 235–253. Bibcode:1983Ap&SS..95..235G. doi:10.1007/BF00653631. S2CID 122101052.
  6. ^ a b c Mohanty, Subhanjoy; et al. (2003). "Rotation and activity in mid-M to L field dwarfs". The Astrophysical Journal. 583 (1): 451–472. arXiv:astro-ph/0201455. Bibcode:2003ApJ...583..451M. doi:10.1086/345097. S2CID 119463177.
  7. ^ Houdebine, Éric R.; Mullan, D. J.; Doyle, J. G.; de la Vieuville, Geoffroy; Butler, C. J.; Paletou, F. (2019). "The Mass-Activity Relationships in M and K Dwarfs. I. Stellar Parameters of Our Sample of M and K Dwarfs". The Astronomical Journal. 158 (2): 56. arXiv:1905.07921. Bibcode:2019AJ....158...56H. doi:10.3847/1538-3881/ab23fe. S2CID 159041104.
  8. ^ a b c d e f Pineda, J. Sebastian; Youngblood, Allison; France, Kevin (September 2021). "The M-dwarf Ultraviolet Spectroscopic Sample. I. Determining Stellar Parameters for Field Stars". The Astrophysical Journal. 918 (1): 23. arXiv:2106.07656. Bibcode:2021ApJ...918...40P. doi:10.3847/1538-4357/ac0aea. S2CID 235435757. 40.
  9. ^ a b Cantrell, Justin R.; et al. (October 2013). "The Solar Neighborhood XXIX: The Habitable Real Estate of Our Nearest Stellar Neighbors". The Astronomical Journal. 146 (4): 99. arXiv:1307.7038. Bibcode:2013AJ....146...99C. doi:10.1088/0004-6256/146/4/99. S2CID 44208180.
  10. ^ Fuhrmeister, B.; et al. (September 2005). "PHOENIX model chromospheres of mid- to late-type M dwarfs". Astronomy and Astrophysics. 439 (3): 1137–1148. arXiv:astro-ph/0505375. Bibcode:2005A&A...439.1137F. doi:10.1051/0004-6361:20042338. S2CID 16499769.
  11. ^ Mann, Andrew W.; et al. (May 2015). "How to Constrain Your M Dwarf: Measuring Effective Temperature, Bolometric Luminosity, Mass, and Radius". The Astrophysical Journal. 804 (1): 38. arXiv:1501.01635. Bibcode:2015ApJ...804...64M. doi:10.1088/0004-637X/804/1/64. S2CID 19269312. 64.
  12. ^ Díez Alonso, E.; Caballero, J. A.; Montes, D.; De Cos Juez, F. J.; Dreizler, S.; Dubois, F.; Jeffers, S. V.; Lalitha, S.; Naves, R.; Reiners, A.; Ribas, I.; Vanaverbeke, S.; Amado, P. J.; Béjar, V. J. S.; Cortés-Contreras, M.; Herrero, E.; Hidalgo, D.; Kürster, M.; Logie, L.; Quirrenbach, A.; Rau, S.; Seifert, W.; Schöfer, P.; Tal-Or, L. (2019). "CARMENES input catalogue of M dwarfs. IV. New rotation periods from photometric time series". Astronomy and Astrophysics. 621: A126. arXiv:1810.03338. Bibcode:2019A&A...621A.126D. doi:10.1051/0004-6361/201833316. S2CID 111386691.
  13. ^ a b Lafarga, M.; Ribas, I.; Reiners, A.; Quirrenbach, A.; Amado, P. J.; Caballero, J. A.; Azzaro, M.; Béjar, V. J. S.; Cortés-Contreras, M.; Dreizler, S.; Hatzes, A. P.; Henning, Th.; Jeffers, S. V.; Kaminski, A.; Kürster, M.; Montes, D.; Morales, J. C.; Oshagh, M.; Rodríguez-López, C.; Schöfer, P.; Schweitzer, A.; Zechmeister, M. (2021). "The CARMENES search for exoplanets around M dwarfs. Mapping stellar activity indicators across the M dwarf domain". Astronomy and Astrophysics. 652: 652. arXiv:2105.13467. Bibcode:2021A&A...652A..28L. doi:10.1051/0004-6361/202140605. S2CID 235248016.
  14. ^ a b c Bowens-Rubin, Rachel; Akana Murphy, Joseph M.; et al. (December 2023). "A Wolf 359 in sheep's clothing: Hunting for substellar companions in the fifth-closest system using combined high-contrast imaging and radial velocity analysis". The Astronomical Journal. 166 (6): 260. arXiv:2309.03402. Bibcode:2023AJ....166..260B. doi:10.3847/1538-3881/ad03e5.
  15. ^ "V* CN Leo -- Flare Star". SIMBAD. Centre de Données astronomiques de Strasbourg. Retrieved 2007-07-16.
  16. ^ Weir, Andy (2022). Project Hail Mary. London: Penguin Books. ISBN 978-1-5291-5746-8.
  17. ^ a b McLean, Ian S.; et al. (October 2003). "The NIRSPEC brown dwarf spectroscopic survey. I. low-resolution near-infrared spectra". The Astrophysical Journal. 596 (1): 561–586. arXiv:astro-ph/0309257. Bibcode:2003ApJ...596..561M. doi:10.1086/377636. S2CID 1939667.
  18. ^ Wolf, M. (1919). "Katalog von 1053 staerker bewegten Fixsternen". Veroeffentlichungen der Badischen Sternwarte zu Heidelberg. 7 (10): 195–219, 206. Bibcode:1919VeHei...7..195W.
  19. ^ Wolf, M. (July 1917). "Eigenbewegungssterne". Astronomische Nachrichten. 204 (20): 345–350. Bibcode:1917AN....204..345W. doi:10.1002/asna.19172042002.
  20. ^ van Maanen, Adriaan (1928). "The photographic determination of stellar parallaxes with the 60- and 100-inch reflectors. Fifteenth Series". Contributions from the Mount Wilson Observatory. 356: 1–27. Bibcode:1928CMWCI.356....1V.
  21. ^ van Biesbroeck, G. (August 1944). "The star of lowest known luminosity". The Astronomical Journal. 51: 61–62. Bibcode:1944AJ.....51...61V. doi:10.1086/105801.
  22. ^ Kron, G. E.; et al. (1957). "Red and infrared magnitudes for 282 stars with known trigonometric parallaxes". Astronomical Journal. 62: 205–220. Bibcode:1957AJ.....62..205K. doi:10.1086/107521.
  23. ^ Greenstein, Jesse L.; et al. (August 1970). "The faint end of the main sequence". Astrophysical Journal. 161: 519. Bibcode:1970ApJ...161..519G. doi:10.1086/150556.
  24. ^ a b Reiners, Ansgar; et al. (2007). "Rapid magnetic flux variability on the flare star CN Leonis". Astronomy and Astrophysics. 466 (2): L13–L16. arXiv:astro-ph/0703172. Bibcode:2007A&A...466L..13R. doi:10.1051/0004-6361:20077095. S2CID 17926213.
  25. ^ Mukai, K.; et al. (August 1990). "Spectroscopy of faint, high latitude cataclysmic variable candidates". Monthly Notices of the Royal Astronomical Society. 245 (3): 385–391. Bibcode:1990MNRAS.245..385M. doi:10.1093/mnras/245.3.385.
  26. ^ a b Robinson, R. D.; et al. (1995). "A search for microflaring activity on dMe flare stars. I. Observations of the dM8e Star CN Leonis". Astrophysical Journal. 451: 795–805. Bibcode:1995ApJ...451..795R. doi:10.1086/176266.
  27. ^ Jones, Lauren V. (2009). Stars and galaxies. Greenwood Guides to the Universe. ABC-CLIO. p. 50. ISBN 978-0-313-34075-8.
  28. ^ a b c d e Pavlenko, Ya. V.; et al. (2006). "Spectral energy distribution for GJ406". Astronomy and Astrophysics. 447 (2): 709–717. arXiv:astro-ph/0510570. Bibcode:2006A&A...447..709P. doi:10.1051/0004-6361:20052979. S2CID 119068354.
  29. ^ Borgia, Michael P. (2006). Human vision and the night sky: hot [i.e. how] to improve your observing skills. Patrick Moore's practical astronomy series. Springer. p. 208. ISBN 978-0-387-30776-3.
  30. ^ Dantona, F.; et al. (September 15, 1985). "Evolution of very low mass stars and brown dwarfs. I - The minimum main-sequence mass and luminosity". Astrophysical Journal, Part 1. 296: 502–513. Bibcode:1985ApJ...296..502D. doi:10.1086/163470.
  31. ^ Brown, T. M.; et al. (1998). "Accurate determination of the solar photospheric radius". Astrophysical Journal Letters. 500 (2): L195. arXiv:astro-ph/9803131. Bibcode:1998ApJ...500L.195B. doi:10.1086/311416. S2CID 13875360. The radius of the Sun is 695.5 Mm. 16% of this is 111 Mm.
  32. ^ Harvey, Samantha (March 4, 2010). "Jupiter: facts & figures". Solar System Exploration. NASA. Archived from the original on December 15, 2003. Retrieved 2010-05-28.
  33. ^ McCook, G. P.; et al. (1995). "Fully convective M dwarfs". Villanova University. Archived from the original on 2011-06-15. Retrieved 2010-05-17.
  34. ^ Adams, Fred C.; et al. (December 2004). "Red dwarfs and the end of the main sequence". Gravitational Collapse: From Massive Stars to Planets. Revista Mexicana de Astronomía y Astrofísica. pp. 46–49. Bibcode:2004RMxAC..22...46A.
  35. ^ 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.
  36. ^ Gautier, T. N.; et al. (2007). "Far infrared properties of M dwarfs". The Astrophysical Journal. 667 (1): 527–. arXiv:0707.0464. Bibcode:2007ApJ...667..527G. doi:10.1086/520667. S2CID 15732144.
  37. ^ Lestrade, J.-F.; et al. (November 2009). "Search for cold debris disks around M-dwarfs. II". Astronomy and Astrophysics. 506 (3): 1455–1467. arXiv:0907.4782. Bibcode:2009A&A...506.1455L. doi:10.1051/0004-6361/200912306. S2CID 17035185.
  38. ^ Casagrande, Luca; et al. (September 2008). "M dwarfs: effective temperatures, radii and metallicities". Monthly Notices of the Royal Astronomical Society. 389 (2): 585–607. arXiv:0806.2471. Bibcode:2008MNRAS.389..585C. doi:10.1111/j.1365-2966.2008.13573.x. S2CID 14353142.
  39. ^ Verschuur, Gerrit L. (2003). Interstellar matters: essays on curiosity and astronomical discovery. Springer. pp. 253–254. ISBN 978-0-387-40606-0.
  40. ^ Pavlenko, Y. V.; et al. (December 2002). "Carbon monoxide bands in M dwarfs". Astronomy and Astrophysics. 396 (3): 967–975. arXiv:astro-ph/0210017. Bibcode:2002A&A...396..967P. doi:10.1051/0004-6361:20021454. S2CID 8384149.
  41. ^ Pesch, Peter (June 1972). "CaOH, a new triatomic molecule in stellar atmospheres". Astrophysical Journal. 174: L155. Bibcode:1972ApJ...174L.155P. doi:10.1086/180970.
  42. ^ Schmitt, J. H. M. M.; et al. (2001). "Ground-based observation of emission lines from the corona of a red-dwarf star". Nature. 412 (2): 508–510. Bibcode:2001Natur.412..508S. doi:10.1038/35087513. PMID 11484044. S2CID 4415051.
  43. ^ Liefke, C.; Reiners, A.; Schmitt, J. H. M. M. (January 2007). "Magnetic field variations and a giant flare Multiwavelength observations of CN Leo". Memorie della Societa Astronomica Italiana. 78: 258–260. Bibcode:2007MmSAI..78..258L.
  44. ^ Staff (January 7, 2007). "Calling Dr. Frankenstein! : interactive binaries show signs of induced hyperactivity". National Optical Astronomy Observatory.
  45. ^ Schmitt, J. H. M. M.; et al. (September 1995). "The X-ray view of the low-mass stars in the solar neighborhood". Astrophysical Journal. 450 (9): 392–400. Bibcode:1995ApJ...450..392S. doi:10.1086/176149.
  46. ^ Cwiok, M.; et al. (March 2006). "Search for optical counterparts of gamma ray burst". Acta Physica Polonica B. 37 (3): 919. Bibcode:2006AcPPB..37..919C.
  47. ^ Röser, Siegfried (2008). Reviews in modern astronomy, cosmic matter. Wiley-VCH. pp. 49–50, 57. ISBN 978-3-527-40820-7.
  48. ^ Staff (June 8, 2007). "List of the nearest 100 stellar systems". Research Consortium on Nearby Stars. Retrieved 2007-07-16.
  49. ^ Gliese, W. (1969). "Catalogue of nearby stars". Veröffentlichungen des Astronomischen Rechen-Instituts Heidelberg. 22: 1. Bibcode:1969VeARI..22....1G.
  50. ^ Allen, C.; et al. (1998). "The galactic orbits of nearby UV Ceti stars". Revista Mexicana de Astronomía y Astrofísica. 34: 37–46. Bibcode:1998RMxAA..34...37A.
  51. ^ "Wolf 359". SolStation Company. Retrieved 2006-08-10.
  52. ^ "Annotations on V* CN Leo object". SIMBAD. Centre de Données astronomiques de Strasbourg. Retrieved 2010-04-13.
  53. ^ Rodler, F.; et al. (February 2012). "Search for radial velocity variations in eight M-dwarfs with NIRSPEC/Keck II". Astronomy & Astrophysics. 538: A141. arXiv:1112.1382. Bibcode:2012A&A...538A.141R. doi:10.1051/0004-6361/201117577. S2CID 56103966.
  54. ^ a b Tuomi, M.; Jones, H. R. A.; Anglada-Escudé, G.; Butler, R. P.; Arriagada, P.; Vogt, S. S.; Burt, J.; Laughlin, G.; Holden, B.; Teske, J. K.; Shectman, S. A.; Crane, J. D.; Thompson, I.; Keiser, S.; Jenkins, J. S.; Berdiñas, Z.; Diaz, M.; Kiraga, M.; Barnes, J. R. (2019). "Frequency of planets orbiting M dwarfs in the Solar neighbourhood". arXiv:1906.04644 [astro-ph.EP].
  55. ^ Ribas, I.; Reiners, A.; et al. (February 2023). "The CARMENES search for exoplanets around M dwarfs. Guaranteed time observations Data Release 1 (2016-2020)". Astronomy & Astrophysics. 670. arXiv:2302.10528. Bibcode:2023A&A...670A.139R. doi:10.1051/0004-6361/202244879.
[edit]