Luyten b

Last updated
Luyten b
Discovery [1]
Discovered by Astudillo-Defru et al., HARPS
Discovery date17 March 2017
Radial velocity
Orbital characteristics [1]
0.091101+0.000019
−0.000017
  AU
Eccentricity 0.10+0.09
−0.07
18.6498+0.0059
−0.0052
  d
Semi-amplitude 1.61±0.15  m/s
Star Luyten's Star
Physical characteristics
Mass ≥2.89+0.27
−0.26
  M🜨
Temperature 259 K (−14 °C; 7 °F) [2]

    Luyten b (more commonly known as Gliese 273b) is a confirmed exoplanet, likely rocky, orbiting within the habitable zone of the nearby red dwarf Luyten's Star. It is the fourth-closest potentially habitable exoplanet known, at a distance of 12 light-years. Only Proxima Centauri b, Ross 128 b, and GJ 1061 d are closer. Discovered alongside Gliese 273c in June 2017, Luyten b is a super-Earth of around 2.89 times the mass of Earth and receives only 6% more starlight than Earth, making it one of the best candidates for habitability. [1]

    Contents

    Characteristics

    Mass, radius, and temperature

    Mass and size

    Luyten b is a super-Earth, meaning that it has a mass and/or radius greater than that of Earth, but less than that of Uranus or Neptune. Radial velocity measurements shows that the planet has a minimum mass of 2.89  M 🜨 , placing it at the lower end of the super-Earth range. [1] The planet has not been found to transit its star, and as a result its true mass and radius are not known. Due to its low mass, the planet is likely terrestrial, with a predicted radius of 1.51  R 🜨 . [3]

    Up to four candidate planets have been proposed around Luyten's Star. A 2020 study showed that if all four planets are present, their true masses must be close to their minimum masses for the system to be stable, with an upper limit of 3.03 M🜨 for Luyten b. [4]

    Temperature and atmosphere

    The planet receives an incident flux only 6% greater than that of Earth. [1] With an estimated albedo, or proportion of light reflected by the planet, of 0.30, Luyten b has an equilibrium temperature of 259 K. [2] For comparison, Earth has an equilibrium temperature of 255 K. With an Earth-like atmosphere — if it has one — Luyten b would have an average surface temperature of about 292 K (19 °C; 66 °F), very similar to that of Earth.

    Orbit and rotation

    Luyten b orbits quite close to its host star. One full revolution around Luyten's Star takes about 18.6 days at an average distance of 0.091  AU, much closer in than Mercury, which has a year of 88 days and an orbital radius of 0.387 AU. However, because the host star is so dim, Luyten b falls right within the system's habitable zone and only receives 6% more starlight than Earth. Luyten b has a moderate orbital eccentricity of 0.10 ± 0.08. [1]

    Host star

    Luyten's Star is a medium-sized red dwarf star on the main sequence. It has 29.3% the radius, 29% the mass, 0.88% the luminosity of the Sun, and has an effective temperature of 3,382 K. Unlike many nearby red dwarfs, like Proxima Centauri, Luyten's Star is very inactive with a long rotation period of over 118 days. [1]

    Active SETI

    In October 2017 and 2018, the nonprofit organization METI (Messaging Extraterrestrial Intelligence) sent a message, "Sónar Calling GJ273b", containing dozens of short musical compositions and a scientific "tutorial" towards the planet in hopes of contacting any potential extraterrestrial civilizations. [5]

    See also

    Related Research Articles

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    <span class="mw-page-title-main">Gliese 581d</span> Contested super-Earth orbiting Gliese 581

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    <span class="mw-page-title-main">Super-Earth</span> Planet with a mass between Earth and Uranus

    A Super-Earth is a type of exoplanet with a mass higher than Earth's, but substantially below those of the Solar System's ice giants, Uranus and Neptune, which are 14.5 and 17 times Earth's, respectively. The term "super-Earth" refers only to the mass of the planet, and so does not imply anything about the surface conditions or habitability. The alternative term "gas dwarfs" may be more accurate for those at the higher end of the mass scale, although "mini-Neptunes" is a more common term.

    <span class="mw-page-title-main">Discoveries of exoplanets</span> Detecting planets located outside the Solar System

    An exoplanet is a planet located outside the Solar System. The first evidence of an exoplanet was noted as early as 1917, but was not recognized as such until 2016; no planet discovery has yet come from that evidence. What turned out to be the first detection of an exoplanet was published among a list of possible candidates in 1988, though not confirmed until 2003. The first confirmed detection came in 1992, with the discovery of terrestrial-mass planets orbiting the pulsar PSR B1257+12. The first confirmation of an exoplanet orbiting a main-sequence star was made in 1995, when a giant planet was found in a four-day orbit around the nearby star 51 Pegasi. Some exoplanets have been imaged directly by telescopes, but the vast majority have been detected through indirect methods, such as the transit method and the radial-velocity method. As of 1 October 2023, there are 5,506 confirmed exoplanets in 4,065 planetary systems, with 878 systems having more than one planet. This is a list of the most notable discoveries.

    <span class="mw-page-title-main">Gliese 667 Cc</span> Goldilocks super-Earth orbiting Gliese 667 C

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    <span class="mw-page-title-main">Gliese 180</span> Star in the constellation Eridanus

    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.

    <span class="mw-page-title-main">Wolf 1061c</span> Super-Earth orbiting Wolf 1061

    Wolf 1061c is an exoplanet orbiting within the habitable zone of the red dwarf star Wolf 1061 in the constellation Ophiuchus, about 13.8 light years from Earth, making it the fifth closest known, potentially habitable, and confirmed exoplanet to Earth, yielding interest from astronomers. It is the second planet in order from its host star in a triple planetary system, and has an orbital period of 17.9 days. Wolf 1061c is classified as a super-Earth exoplanet as its estimated radius is greater than 1.5 R🜨.

    Wolf 1061d is an exoplanet orbiting the red dwarf star Wolf 1061 in the Ophiuchus constellation, about 13.8 light years from Earth. It is the third and furthest planet in order from its host star in a triple planetary system, and has an orbital period of about 217 days.

    Mikko Tuomi is a Finnish astronomer from the University of Hertfordshire, most known for his contributions to the discovery of a number of exoplanets, among them the Proxima Centauri b which orbits the closest star to the Sun. Mikko Tuomi was the first to find indications of the existence of Proxima Centauri b in archival observation data. Other exoplanets to whose discovery or study Tuomi has contributed include HD 40307, HD 154857 c, Kapteyn c, Gliese 682 c, HD 154857, Gliese 221, Gliese 581 g and the planetary system orbiting Tau Ceti. He has led the development of new data analysis techniques for distinguishing observations caused by natural activity of the star and those caused by planets orbiting them.

    <span class="mw-page-title-main">LHS 1140 b</span> Super-Earth orbiting LHS 1140

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    <span class="mw-page-title-main">Ross 128 b</span> Confirmed terrestrial exoplanet orbiting Ross 128

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    <span class="mw-page-title-main">Teegarden's Star c</span> Candidate terrestrial exoplanet orbiting Teegardens Star

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    <span class="mw-page-title-main">GJ 1002</span> Red dwarf star in the constellation Cetus

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    References

    1. 1 2 3 4 5 6 7 Astudillo-Defru, Nicola; Forveille, Thierry; Bonfils, Xavier; Ségransan, Damien; Bouchy, François; Delfosse, Xavier; et al. (2017). "The HARPS search for southern extra-solar planets. XLI. A dozen planets around the M dwarfs GJ 3138, GJ 3323, GJ 273, GJ 628, and GJ 3293". Astronomy and Astrophysics. 602. A88. arXiv: 1703.05386 . Bibcode:2017A&A...602A..88A. doi:10.1051/0004-6361/201630153. S2CID   119418595.
    2. 1 2 "PHL's calculators". Archived from the original on 2021-10-18. Retrieved 2017-11-16.
    3. "NASA exoplanet catalog GJ 273 b".
    4. Pozuelos, Francisco J.; Suárez, Juan C.; de Elía, Gonzalo C.; Berdiñas, Zaira M.; Bonfanti, Andrea; Dugaro, Agustín; et al. (2020). "GJ 273: On the formation, dynamical evolution, and habitability of a planetary system hosted by an M dwarf at 3.75 parsec". Astronomy & Astrophysics. 641: A23. arXiv: 2006.09403 . Bibcode:2020A&A...641A..23P. doi:10.1051/0004-6361/202038047. S2CID   219721292.
    5. "Sonar Calling". Website. Advanced Music SL. Retrieved 6 May 2019.