Lalande 21185

Last updated
Lalande 21185
Ursa Major IAU.svg
Cercle rouge 100%25.svg
The red circle shows the approximate location of Lalande 21185 in Ursa Major
Observation data
Epoch J2000.0        Equinox J2000.0
Constellation Ursa Major
Right ascension 11h 03m 20.19482s [1]
Declination +35° 58′ 11.5762″ [1]
Apparent magnitude  (V)7.520 [2]
Characteristics
Spectral type M2V [3]
Apparent magnitude  (B)8.960 ± 0.007 [2]
Apparent magnitude  (V)7.520 ± 0.009 [2]
Apparent magnitude  (R)~6.6 [3]
Apparent magnitude  (I)~5.8 [3]
Apparent magnitude  (J)4.203 ±0.242 [3]
Apparent magnitude  (H)3.640 ±0.202 [3]
Apparent magnitude  (K)3.254 ±0.306 [3]
U−B color index +1.074 [2]
B−V color index +1.444 [2]
Variable type BY [4]
Astrometry
Radial velocity (Rv)−85.11±0.13 [1]  km/s
Proper motion (μ)RA: −580.057  mas/yr [1]
Dec.: −4776.589  mas/yr [1]
Parallax (π)392.7529 ± 0.0321  mas [1]
Distance 8.3044 ± 0.0007  ly
(2.5461 ± 0.0002  pc)
Absolute magnitude  (MV)10.48 [5]
Details
Mass 0.389±0.008 [6]   M☉
Radius 0.392±0.004 [6]   R☉
Luminosity (bolometric)0.02194±0.00021 [6]   L☉
Luminosity (visual, LV)0.0055 [nb 1]   L☉
Surface gravity (log g)4.87±0.07 [7]   cgs
Temperature 3,547±18 [6]   K
Metallicity [Fe/H]−0.3621+0.0872
−0.0687 [8]   dex
Rotation 56.15±0.27 d [7]
Age 8.047+3.958
−4.523 [8]   Gyr
Other designations
NSV  18593, BD+36 2147, GJ  411, HD  95735, HIP  54035, SAO  62377, G 119-052, LFT  756, LHS  37, LTT  12960, NLTT  26105, PLX  2576, IRAS 11005+3615, 2MASS J11032023+3558117, J11032027+3558203, MCC 594 [3]
Database references
SIMBAD data
Exoplanet Archive data
ARICNS data

Lalande 21185 (also known as BD+36 2147, Gliese 411, and HD 95735 [3] ) is a star in the south of Ursa Major. It is the apparent brightest red dwarf in the northern hemisphere. [nb 2] [9] [10] Despite this, and being relatively close by, it is very dim (as are all red dwarfs), being only magnitude 7.5 in visible light and thus too faint to be seen with the unaided eye. The star is visible through a small telescope or binoculars. [11]

Contents

At 8.304 light-years (2.546 parsecs ) [1] away it is one of the stars nearest to the Solar System; only the Alpha Centauri system, Barnard's Star, Wolf 359, and the brown dwarfs Luhman 16 and WISE 0855−0714 are known to be closer. [12] Because of its proximity it is a frequent subject for astronomical surveys and other research and thus is known by numerous other designations, most commonly Gliese 411 and HD 95735. In approximately 19,900 years it will be at its closest, about 4.65 ly (1.43 pc) from the Sun, just over half its present distance. [13] [14]

Lalande 21185 has two known exoplanets and one candidate exoplanet, making it the second closest confirmed planetary system to the Solar System.

History

Distances of the nearest stars from 20,000 years ago until 80,000 years in the future Near-stars-past-future-en.svg
Distances of the nearest stars from 20,000 years ago until 80,000 years in the future

The celestial coordinates of Lalande 21185 were first published in 1801 by French astronomer Jérôme Lalande of the Paris Observatory in the star catalog Histoire céleste française . The catalog sequence numbers for majority of the observed stars, including this one, were introduced in its 1847 edition by Francis Baily. [15] [16] Today this star is one of just a few that are still commonly referred to by their Lalande catalog number. [17]

In May 1857, Friedrich Wilhelm Argelander discovered the high proper motion of the star. It was sometimes called "Argelander's second star". [18] [19] [20] (The "first Argelander's star" is Groombridge 1830, whose high proper motion was discovered by Argelander earlier—in 1842).

Friedrich August Theodor Winnecke is reported to have made the first measurement of the star's parallax of 0.511 arc seconds in 1857–58 and thus first identifying Lalande 21185 as the second-closest-known star to the Sun, after the Alpha Centauri system. [19] Since that time better measurements have placed the star farther away, but it remained the second-closest-known star system until the astrophotographic discovery of two dim red dwarfs, Wolf 359 and Barnard's Star, in the early 20th century. [21]

Properties

An X-ray light curve for a flare on NSV 18593, adapted from Pye et al. (2015) NSV18593LightCurve.png
An X-ray light curve for a flare on NSV 18593, adapted from Pye et al. (2015)
The position of Lalande 21185 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. Angular map of fusors around Sol within 9ly (large).png
The position of Lalande 21185 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.

Lalande 21185 is a typical type-M main-sequence star (red dwarf) with about 39% of the mass and radius of the Sun. It is also much cooler than the Sun with a surface temperature of 3,550 K. With just 2.2% of the Sun's luminosity, [6] it is intrinsically dim with an absolute magnitude of 10.48, emitting most of its energy in the infrared. [5] The proportion of elements other than hydrogen and helium is estimated based on the ratio of iron to hydrogen in the star when compared to the Sun. The logarithm of this ratio is −0.20, indicating that the proportion of iron is about 10−0.20, or 63% of the Sun. The surface gravity of this relatively compact star is approximately 65 times greater than the gravity at Earth's surface (log g = 4.8 cgs), [23] which is more than twice the surface gravity of the Sun.

Lalande 21185 is listed as a BY Draconis type variable star in the General Catalogue of Variable Stars. It is identified by the variable star designation NSV 18593. [4] Several star catalogs, including SIMBAD, also classify it as a flare star. This conclusion is not supported by the primary reference these catalogs all use. The observations made in this reference show that it is rather quiet in comparison to other stars of its variable type. [24]

Lalande 21185 emits X-rays, and X-ray flares have been observed. [25] [22]

Planetary system

Data published in 2017 from the HIRES system at the Keck Observatory on Mauna Kea supported the existence of a close-in planet with an orbital period of just 9.8693±0.0016 days, being at least 3.8  ME. [26] Further radial velocity research with the SOPHIE échelle spectrograph and review of the original signal found that the 9.9 day period was undetectable, and instead proposed, using both datasets, an exoplanet orbiting the star with a period of either 12.95 or 1.08 days, much more likely 12.95, insofar as 1-day-period exoplanets seem to be rare in systems. This would give the planet a minimum mass of 2.99 Earth masses. It is too close to the star, and so therefore too hot, to be in the habitable zone, at all points within its eccentric orbit. [27] The proposed planet on 12-day orbit was confirmed by CARMENES  [ ja ] (Calar Alto high-Resolution search for M dwarfs with Exoearths with Near-infrared and optical Echelle Spectrographs) project in 2020. [7]

A second planet with a more distant orbit was initially noticed by SOPHIE, but the baseline was not long enough to confirm the several-year-long signal. The signal was confirmed in 2021 to be a planet with mass at least 18.0+2.9
−2.6 M🜨, [28] a lower-bound estimate later revised to 14.2±1.8 M🜨. [8]

A third planet, Gliese 411 d, is suspected to orbit between Gliese 411 b and Gliese 411 c with a period of 215 days. [8]

The Lalande 21185 planetary system [8]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b≥2.64±0.19  M🜨 0.0788+0.00056
−0.00057		12.9395+0.0013
−0.0012		0.052+0.057
−0.037		——
d(unconfirmed)≥4.1±0.6 M🜨 0.5141+0.0038
−0.0039		215.62+0.76
−0.73		0.15+0.16
−0.11		——
c≥14.2±1.8  M🜨 2.845+0.077
−0.067		2806+110
−94		0.08+0.1
−0.06		——

The habitable zone for this star, defined as the locations where liquid water could be present on an Earth-like planet, is at a radius of 0.11–0.24  AU, where 1 AU is the average distance from the Earth to the Sun. [29] The planet b has an equilibrium temperature of 370.1+5.8
−6.8 K. Other known planets are outside HZ boundaries too, but undetected low-mass ones may be orbiting in this region of this system as well. [7]

Past claims of planets

Dutch astronomer Peter van de Kamp wrote in 1945 that Lalande 21185 possessed an "unseen companion" of 0.06  M☉ (about 60  MJ). [30] In 1951 van de Kamp and his student Sarah Lippincott claimed the astrometric detection of a planetary system using photographic plates taken with the 24-inch (610 mm) refractor telescope at Swarthmore College's Sproul Observatory. [31] In the summer of 1960, Sarah Lippincott altered the 1951 claim, to a planet of 0.01  M☉ (that is, 10  MJ), an 8-year orbital period, eccentricity of 0.3, a semi-major axis [nb 3] of 0.083  AU . [32] She used the original photographic plates and new plates taken with the same telescope. [33] Photographic plates from this observatory, taken at the same time, were used by Van de Kamp for his erroneous claim of a planetary system for Barnard's Star. The plates made with the Sproul 24-inch refractor and used for these and other studies were in 1973 shown to be flawed; [34] as they were the next year with astrometric measurements made by George Gatewood of the Allegheny Observatory. [35]

In 1996 the same Gatewood prominently announced at an AAS meeting [36] and to the popular press [37] the discovery of multiple planets in this system, detected by astrometry. The initial report was based on a very delicate analysis of the star's position over the years, which suggested reflex orbital motion due to one or more companions. Gatewood claimed that such companions would usually appear more than 0.8 arcseconds from the red dwarf itself. Though, a paper by Gatewood published only a few years earlier [38] and later searches by others, using coronagraphs and multifilter techniques to reduce the scattered-light problems from the star, did not positively identify any such companions, [39] and so his claim remains unconfirmed and is now in doubt.

Before the 1980s, finding the radial velocity of red dwarfs was neither very accurate nor consistent, and so due to its apparent brightness and because it does not have a companion, this star, along with eleven other similar red dwarf stars, were chosen to have their radial velocity measured, to unprecedented high accuracy, by planet hunter Geoff Marcy. [40] No companion was detected around this star in this nor other contemporary surveys, and such early equipment would have picked up any planet exceeding 0.7 MJ in an extremely close orbit of 5 days or less; or exceeding 10 MJ at about Jupiter's orbital distance. [40]

See also

Related Research Articles

<span class="mw-page-title-main">Red dwarf</span> Dim, low mass stars on the main sequence

A red dwarf is the smallest kind of star on the main sequence. Red dwarfs are by far the most common type of fusing star in the Milky Way, at least in the neighborhood of the Sun. However, due to their low luminosity, individual red dwarfs cannot be easily observed. From Earth, not one star that fits the stricter definitions of a red dwarf is visible to the naked eye. Proxima Centauri, the star nearest to the Sun, is a red dwarf, as are fifty of the sixty nearest stars. According to some estimates, red dwarfs make up three-quarters of the fusing stars in the Milky Way.

Chi<sup>1</sup> Orionis Star in the constellation Orion

Chi1 Orionis is a star about 28 light years away. It is in the constellation Orion, where it can be seen in the tip of the hunter's upraised club.

<span class="mw-page-title-main">Gliese 570</span> Quaternary star system in the constellation Libra

Gliese 570 is a quaternary star system approximately 19 light-years away. The primary star is an orange dwarf star. The other secondary stars are themselves a binary system, two red dwarfs that orbit the primary star. A brown dwarf has been confirmed to be orbiting in the system. In 1998, an extrasolar planet was thought to orbit the primary star, but it was discounted in 2000.

<span class="mw-page-title-main">Gliese 876</span> Star in the constellation Aquarius

Gliese 876 is a red dwarf star 15.2 light-years away from Earth in the constellation of Aquarius. It is one of the closest known stars to the Sun confirmed to possess a planetary system with more than two planets, after GJ 1061, YZ Ceti, Tau Ceti, and Wolf 1061; as of 2018, four extrasolar planets have been found to orbit the star. The planetary system is also notable for the orbital properties of its planets. It is the only known system of orbital companions to exhibit a near-triple conjunction in the rare phenomenon of Laplace resonance. It is also the first extrasolar system around a normal star with measured coplanarity. While planets b and c are located in the system's habitable zone, they are giant planets believed to be analogous to Jupiter.

<span class="mw-page-title-main">Rho Coronae Borealis</span> Star in the constellation Corona Borealis

Rho Coronae Borealis is a yellow dwarf star 57.1 light-years away in the constellation of Corona Borealis. The star is thought to be similar to the Sun with nearly the same mass, radius, and luminosity. It is orbited by four known exoplanets.

<span class="mw-page-title-main">Gliese 687</span> Star in the constellation Draco

Gliese 687, or GJ 687 (Gliese–Jahreiß 687) is a red dwarf in the constellation Draco. This is one of the closest stars to the Sun and lies at an approximate distance of less than 15 light years. Even though it is close by, it has a magnitude of about 9, so it can only be seen through a moderately sized telescope. Gliese 687 has a high proper motion, advancing 1.304 arcseconds per year across the sky. It has a net relative velocity of about 39 km/s. It is known to have a Neptune-mass planet. Old books and articles refer to it as Argelander Oeltzen 17415.

Gliese 849, or GJ 849, is a small, solitary star in the equatorial constellation of Aquarius. It has a reddish hue and is invisible to the naked eye with an apparent visual magnitude of 10.41. The distance to this star is 28.8 light-years based on parallax, but it is drifting closer to the Sun with a radial velocity of −15.3 km/s. It has a pair of confirmed gas giant companions.

Gliese 317 is a small red dwarf star with two exoplanetary companions in the southern constellation of Pyxis. It is located at a distance of 49.6 light-years from the Sun based on parallax measurements, and is drifting further away with a radial velocity of +87.8 km/s. This star is too faint to be viewed with the naked eye, having an apparent visual magnitude of 11.98 and an absolute magnitude of 11.06.

Gliese 86 is a K-type main-sequence star approximately 35 light-years away in the constellation of Eridanus. It has been confirmed that a white dwarf orbits the primary star. In 1998 the European Southern Observatory announced that an extrasolar planet was orbiting the star.

George David Gatewood also known as George G. Gatewood, is an American astronomer and presently is professor emeritus at the University of Pittsburgh and at the Allegheny Observatory. He specializes in astronomy, astronomical instrumentation, statistical methods, stellar astrophysics, astrometric properties of nearby stars and the observational discovery and the study of planetary systems. He came to popular attention with his 1996 announcement of the discovery of a nearby multi-planet star system. This discovery has yet to be confirmed and is regarded with skepticism today.

Gliese 433 is a dim red dwarf star with multiple exoplanetary companions, located in the equatorial constellation of Hydra. The system is located at a distance of 29.6 light-years from the Sun based on parallax measurements, and it is receding with a radial velocity of +18 km/s. Based on its motion through space, this is an old disk star. It is too faint to be viewed with the naked eye, having an apparent visual magnitude of 9.81 and an absolute magnitude of 10.07.

Gliese 649 is a small star with an orbiting exoplanet in the constellation Hercules. It has an apparent visual magnitude of 9.7, which is too faint to be seen with the naked eye. The system is located at a distance of 33.9 light years based on parallax, and is drifting further away with a radial velocity of 3.8 km/s.

Gliese 179 is a small red dwarf star with an exoplanetary companion in the equatorial constellation of Orion. It is much too faint to be visible to the naked eye with an apparent visual magnitude of 11.94. The system is located at a distance of 40.5 light-years from the Sun based on parallax measurements, but is drifting closer with a radial velocity of –9 km/s. It is a high proper motion star, traversing the celestial sphere at an angular rate of 0.370″·yr−1.

Gliese 163 is a faint red dwarf star with multiple exoplanetary companions in the southern constellation of Dorado. Other stellar catalog names for it include HIP 19394 and LHS 188. It is too faint to be visible to the naked eye, having an apparent visual magnitude of 11.79 and an absolute magnitude of 10.91. This system is located at a distance of 49.4 light-years from the Sun based on parallax measurements. Judging by its space velocity components, it is most likely a thick disk star.

Gliese 180, is a small red dwarf star in the equatorial constellation of Eridanus. It is invisible to the naked eye with an apparent visual magnitude of 10.9. The star is located at a distance of 39 light years from the Sun based on parallax, and is drifting closer with a radial velocity of −14.6 km/s. It has a high proper motion, traversing the sky at the rate of 0.765 arcseconds per year.

Gliese 880 is a red dwarf star in the northern constellation of Pegasus that may host an exoplanetary companion. No stellar companions to Gliese 880 have been discovered as of 2020.

Gliese 328, also known as BD+02 2098, is a M-type main-sequence star located 66.9 light-years away in the constellation Hydra. Its surface temperature is 3989 K. Gliese 328 is depleted in heavy elements compared to the Sun, with a metallicity Fe/H index of −0.13. The age of the star is unknown. Gliese 328 exhibits an activity cycle similar to that of the Sun, with a period around 2000 d.

Gliese 514, also known as BD+11 2576 or HIP 65859, is a M-type main-sequence star, in the constellation Virgo 24.85 light-years away from the Sun. The proximity of Gliese 514 to the Sun was known exactly since 1988.

References

  1. 1 2 3 4 5 6 7 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. 1 2 3 4 5 Oja, T. (August 1985), "Photoelectric photometry of stars near the north Galactic pole. II", Astronomy and Astrophysics Supplement Series, 61: 331–339, Bibcode:1985A&AS...61..331O
  3. 1 2 3 4 5 6 7 8 "HD 95735". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2009-05-29.
  4. 1 2 "NSV 18593". General Catalogue of Variable Stars, Sternberg Astronomical Institute, Moscow, Russia. Retrieved 2009-09-09.
  5. 1 2 Johnson, H. M.; Wright, C. D. (November 1983), "Predicted infrared brightness of stars within 25 parsecs of the Sun", Astrophysical Journal Supplement Series, 53: 643–711, Bibcode:1983ApJS...53..643J, doi: 10.1086/190905
  6. 1 2 3 4 5 Pineda, J. Sebastian; et al. (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.
  7. 1 2 3 4 Stock, S.; et al. (2020), "The CARMENES search for exoplanets around M dwarfs Three temperate-to-warm super-Earths", Astronomy & Astrophysics, A112: 643, arXiv: 2010.00474 , Bibcode:2020A&A...643A.112S, doi:10.1051/0004-6361/202038820, S2CID   222090233
  8. 1 2 3 4 5 Hurt, Spencer A.; Fulton, Benjamin; Isaacson, Howard; Rosenthal, Lee J.; Howard, Andrew W.; Weiss, Lauren M.; Petigura, Erik A. (2021), "Confirmation of the Long-Period Planet Orbiting Gliese 411 and the Detection of a New Planet Candidate", The Astronomical Journal, 163 (5): 218, arXiv: 2107.09087 , Bibcode:2022AJ....163..218H, doi: 10.3847/1538-3881/ac5c47 , S2CID   236134034
  9. ↑ Dickinson, David (2015-12-23). "14 Red Dwarf Stars to View with Backyard Telescopes". Universe Today. Retrieved 2016-12-04.
  10. ↑ Croswell, Ken (July 2002). "The Brightest Red Dwarf". KenCroswell.com. Retrieved 2016-12-04.
  11. ↑ Sherrod, P. Clay; Koed, Thomas L. (2003), A Complete Manual of Amateur Astronomy: Tools and Techniques for Astronomical Observations, Astronomy Series, Courier Dover Publications, p. 9, ISBN   978-0486428208
  12. ↑ Reylé, Céline; Jardine, Kevin; Fouqué, Pascal; Caballero, Jose A.; Smart, Richard L.; Sozzetti, Alessandro (30 April 2021). "The 10 parsec sample in the Gaia era". Astronomy & Astrophysics . 650: A201. arXiv: 2104.14972 . Bibcode:2021A&A...650A.201R. doi:10.1051/0004-6361/202140985. S2CID   233476431. Data available at https://gruze.org/10pc/
  13. ↑ García-Sánchez, J.; et al. (2001), "Stellar encounters with the solar system" (PDF), Astronomy and Astrophysics, 379 (2): 634–659, Bibcode:2001A&A...379..634G, doi: 10.1051/0004-6361:20011330
  14. ↑ "Annotations on HD 95735 object". Centre de données astronomiques de Strasbourg. Retrieved 2010-04-14.
  15. ↑ Baily, Francis; Lalande, Joseph Jérôme Le Français de (1847). "Catalogue of those stars in the Histoire céleste française of Jérôme Delalande, for which tables of reduction to the epoch 1800 habe been published by Prof. Schumacher". London (1847). Bibcode:1847cshc.book.....B. Google Books id: oc0-AAAAcAAJ.
  16. ↑ Baily, F. (1847). "A catalogue of those stars in the "Histoire céleste française" of J. De Lalande for which tables of reduction to the session define format EPOCH1 = 1800 have been published by Professor Schumacher". British Ass. Adv. Sci. 1847. Bibcode:1950Lalan1847....0B.
  17. ↑ Joseph-Jérôme de Lalande Archived July 21, 2009, at the Wayback Machine
  18. ↑ Lynn, W. T. (1872). "On the Parallax and Proper Motion of Lalande 21185". Monthly Notices of the Royal Astronomical Society . 33: 52–54. Bibcode:1872MNRAS..33...52L. doi: 10.1093/mnras/33.1.52 .
  19. 1 2 Winnecke, A. (1858). "Über die Parallaxe des zweiten Argelander'schen Sterns, von Herrn Prof. Winnecke". Astronomische Nachrichten . 48 (1147): 289–292. Bibcode:1858AN.....48..289W. doi:10.1002/asna.18580481903.
  20. ↑ Winnecke, Friedrich August Theodor (1872). "Bestimmung der parallaxe des zweiten Argelander-'schen sternes aus messungen AM heliometer der sternwarte zu Bonn in den jahren 1857–1858". Leipzig, W. Engelmann. Astronomische Gesellschaft, Leipzig. Publication11. Leipzig. Bibcode:1872bpza.book.....W. hdl: 2027/nnc1.cu50717758 .
  21. ↑ Russell, H. N. (June 1905). "The parallax of Lalande 21185 and γ Virginis from photographs taken at the Cambridge Observatory". Monthly Notices of the Royal Astronomical Society. 65 (8): 787–800. Bibcode:1905MNRAS..65..787R. doi: 10.1093/mnras/65.8.787 .
  22. 1 2 Pye, J. P.; Rosen, S.; Fyfe, D.; Schröder, A. C. (September 2015). "A survey of stellar X-ray flares from the XMM-Newton serendipitous source catalogue: HIPPARCOS -Tycho cool stars" (PDF). Astronomy & Astrophysics. 581: A28. arXiv: 1506.05289 . Bibcode:2015A&A...581A..28P. doi:10.1051/0004-6361/201526217. S2CID   67794276 . Retrieved 30 June 2022.
  23. ↑ Cayrel de Strobel, G.; et al. (1992), "A catalogue of Fe/H determinations", Astronomy and Astrophysics Supplement Series, 95 (2) (1991 ed.): 273–336, Bibcode:1992A&AS...95..273C, ISSN   0365-0138
  24. ↑ Bopp, B. W.; Noah, P. V.; Klimke, A.; Africano, J. (October 1, 1981). "Discovery and observation of BY Draconis variables". Astrophysical Journal . 249 (1): 210–217. Bibcode:1981ApJ...249..210B. doi: 10.1086/159277 .
  25. ↑ Schmitt JHMM; Fleming TA; Giampapa MS (September 1995). "The X-Ray View of the Low-Mass Stars in the Solar Neighborhood". Astrophys. J. 450 (9): 392–400. Bibcode:1995ApJ...450..392S. doi: 10.1086/176149 .
  26. ↑ Butler, R. Paul; Vogt, Steven S.; et al. (12 February 2017). "The LCES HIRES/Keck Precision Radial Velocity Exoplanet Survey". The Astronomical Journal. 153 (5): 208. arXiv: 1702.03571 . Bibcode:2017AJ....153..208B. doi: 10.3847/1538-3881/aa66ca . S2CID   14954371.
  27. ↑ Díaz, Rodrigo F.; Delfosse, Xavier; Hobson, Melissa J.; Boisse, Isabelle; Astudillo-Defru, Nicola; Bonfils, Xavier; Henry, Gregory W.; Arnold, Luc; Bouchy, François; Bourrier, Vincent; Brugger, Bastien; Dalal, Shweta; Deleuil, Magali; Demangeon, Olivier D. S.; Dolon, François; Dumusque, Xavier; Forveille, Thierry; Hara, Nathan C.; Hébrard, Guillaume; Kiefer, Flavien; Lopez, Théo; Mignon, Lucile; Moreau, François; Mousis, Olivier; Moutou, Claire; Pepe, Francesco; Perruchot, Sandrine; Richaud, Yoann; Santerne, Alexandre; Santos, Nuno C.; Sottile, Rico; Stalport, Manu; Ségransan, Damien; Udry, Stéphane; Unger, Nicolas; Wilson, Paul A. (15 February 2019). "The SOPHIE search for northern extrasolar planets. XIV. A temperate ($T_\mathrm{eq}\sim 300$ K) super-earth around the nearby star Gliese 411". Astronomy & Astrophysics. A17: 625. arXiv: 1902.06004 . doi:10.1051/0004-6361/201935019. S2CID   85529763.
  28. ↑ Rosenthal, Lee J.; Fulton, Benjamin J.; Hirsch, Lea A.; Isaacson, Howard T.; Howard, Andrew W.; Dedrick, Cayla M.; Sherstyuk, Ilya A.; Blunt, Sarah C.; Petigura, Erik A.; Knutson, Heather A.; Behmard, Aida; Chontos, Ashley; Crepp, Justin R.; Crossfield, Ian J. M.; Dalba, Paul A.; Fischer, Debra A.; Henry, Gregory W.; Kane, Stephen R.; Kosiarek, Molly; Marcy, Geoffrey W.; Rubenzahl, Ryan A.; Weiss, Lauren M.; Wright, Jason T. (1 July 2021). "The California Legacy Survey. I. A Catalog of 178 Planets from Precision Radial Velocity Monitoring of 719 Nearby Stars over Three Decades" (PDF). The Astrophysical Journal Supplement Series. 255 (1): 8. arXiv: 2105.11583 . Bibcode:2021ApJS..255....8R. doi: 10.3847/1538-4365/abe23c . S2CID   235186973.
  29. ↑ 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
  30. ↑ van de Kamp, Peter (February 1945). "Stars Nearer than Five Parsecs". Publications of the Astronomical Society of the Pacific . 57 (334): 34–41 (34, 36, 39). Bibcode:1945PASP...57...34V. doi: 10.1086/125679 .
  31. ↑ van de Kamp, P.; Lippincott, S. L. (April 1951). "Astrometric study of Lalande 21185". The Astronomical Journal . 56: 49–50. Bibcode:1951AJ.....56...49V. doi: 10.1086/106503 .
  32. ↑ Lippincott, Sarah Lee (September 1960). "Astrometric analysis of Lalande 21185". Astronomical Journal . 65 (7): 445–448. Bibcode:1960AJ.....65..445L. doi: 10.1086/108285 .
  33. ↑ Lippincott, Sarah Lee (August 1960). "The Unseen Companion of the Fourth Nearest Star, Lalande 21185". The Astronomical Journal . 65: 350. Bibcode:1960AJ.....65..349L. doi:10.1086/108260.
  34. ↑ John L. Hershey (June 1973). "Astrometric analysis of the field of AC +65 6955 from plates taken with the Sproul 24-inch refractor". Astronomical Journal. 78 (5): 421–425. Bibcode:1973AJ.....78..421H. doi: 10.1086/111436 .
  35. ↑ Gatewood, G. (January 1974). "An astrometric study of Lalande 21185". The Astronomical Journal . 79 (1): 52. Bibcode:1974AJ.....79...52G. doi:10.1086/111530.
  36. ↑ Gatewood, G. (May 1996). "Lalande 21185". Bulletin of the American Astronomical Society. 28: 885. Bibcode:1996AAS...188.4011G.
  37. ↑ John Wilford (1996-06-12). "Data Seem to Show a Solar System Nearly in the Neighborhood". The New York Times. p. 1. Retrieved 2009-05-29.
  38. ↑ Gatewood; Stein, John; De Jonge, Joost K.; Persinger, Timothy; Reiland, Thomas; Stephenson, Bruce (September 1992). "Multichannel astrometric photometer and photographic astrometric studies in the regions of Lalande 21185, BD 56°2966, and HR 4784". The Astronomical Journal . 104 (3): 1237–1247. Bibcode:1992AJ....104.1237G. doi: 10.1086/116313 .
  39. ↑ Henry; Baliunas, Sallie L.; Donahue, Robert A.; Fekel, Francis C.; Soon, Willie (March 1, 2000). "Photometric and Ca II H and K Spectroscopic Variations in Nearby Sun-like Stars with Planets. III" (PDF). The Astrophysical Journal. 531 (1): 415–437. Bibcode:2000ApJ...531..415H. doi:10.1086/308466. S2CID   17737644.
  40. 1 2 Marcy; Lindsay, Victoria; Wilson, Karen (June 1987). "Radial velocities of M dwarf stars". Publications of the Astronomical Society of the Pacific. 99: 490–496. Bibcode:1987PASP...99..490M. doi: 10.1086/132010 .

Notes

  1. ↑ From knowing the absolute visual magnitude of Lalande 21185, , and the absolute visual magnitude of the Sun, = , the visual luminosity of Lalande 21185 can therefore be calculated: = 0.005495 Lv⊙
  2. ↑ Only AX Microscopii and Lacaille 9352, in the southern hemisphere, are brighter
  3. ↑ which would be orbital radius if e was 0, that is, a circular orbit
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.