Gliese 581b

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Gliese 581 b
Exoplanet Comparison Gliese 581 b.png
Size comparison of Gliese 581 b with Neptune
(Based on selected hypothetical modeled compositions) [lower-alpha 1]
Discovery [1]
Discovered by X. Bonfils, T. Forveille, X. Delfosse,
S. Udry, M. Mayor, C. Perrier,
F. Bouchy, F. Pepe, D. Queloz,
J.-L. Bertaux
Discovery dateAugust 22, 2005
announced November 30, 2005
Doppler spectroscopy
Orbital characteristics [2]
0.0399±0.0005  AU
Eccentricity 0.0342+0.009
−0.010
5.3686±0.0001  d
Inclination 47°+15°
−13°
2454751.76 ± 0.01 [3]
54°+13°
−14°
Semi-amplitude 12.3±0.1  m/s
Star Gliese 581
Physical characteristics [2]
Mass 20.5+6.2
−3.5
  M🜨

    Gliese 581b or Gl 581b is an exoplanet orbiting within the Gliese 581 system, located 20.5 light-years (6.3 parsecs ) away from Earth in the Libra constellation. It is the first planet discovered of three confirmed in the system so far, and the second in order from the star. [2]

    Contents

    Discovery

    The planet was discovered by a team of French and Swiss astronomers, who announced their findings on November 30, 2005, as a discovery of one of the smallest exoplanets then found, with one conclusion being that planets may be more common around the smallest stars. It was the fifth planet found around a red dwarf star (after Gliese 876's first three planets and Gliese 436 b).

    The planet was discovered using the HARPS instrument, with which they found the host star to have a wobble that implied the existence of the planet.

    The astronomers published their results in Astronomy and Astrophysics Letters . [1]

    Orbit and mass

    Gliese 581b has a minimum mass of approximately 15.8 times the Earth's mass, similar to Neptune's mass. It does not transit its star, implying that its orbital inclination is less than 88.1 degrees. [4] A 2024 study determined the inclination of the planet, allowing its true mass to be determined, which is about 30% greater than the minimum mass at about 20.5 Earth masses. [2]

    The planet is rather close to Gliese 581 and completes a full orbit in only 5.37 days at a mean distance of about 6 million kilometers (0.04 AU). [2] By comparison, Mercury is at a distance of 58 million kilometers (0.387 AU) and completes an orbit in 88 days.

    Characteristics

    Gliese 581b is about 0.04 AU from its sun. It is likely close to Gliese 436 b in mass, temperature, and (with Gliese 876 d) susceptibility to solar effects such as coronal mass ejection. Gliese 581b does not transit. At the least, given that Gliese 581b orbits alongside two other planets (Gliese 581c and e) and that Gliese 436 b (thus far) stands alone, their formation must have differed.

    See also

    Notes

    1. The estimated range of sizes in this image from 2009 is based on the planet's minimum mass. Since the true mass is now known to be somewhat greater, the sizes are likely underestimated, especially if the planet has a hydrogen atmosphere as is likely given its mass.

    Related Research Articles

    <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">Gliese 436</span> Star in the constellation Leo

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    Gliese 581 is a red dwarf star of spectral type M3V which hosts a planetary system, 20.5 light-years away from Earth in the Libra constellation. Its estimated mass is about a third of that of the Sun, and it is the 101st closest known star system to the Sun. Gliese 581 is one of the oldest, least active M dwarfs known. Its low stellar activity improves the likelihood of its planets retaining significant atmospheres, and lessens the sterilizing impact of stellar flares.

    <span class="mw-page-title-main">Gliese 876 b</span> Extrasolar planet orbiting Gliese 876

    Gliese 876 b is an exoplanet orbiting the red dwarf Gliese 876. It completes one orbit in approximately 61 days. Discovered in June 1998, Gliese 876 b was the first planet to be discovered orbiting a red dwarf.

    <span class="mw-page-title-main">Gliese 436 b</span> Hot Neptune exoplanet orbiting Gliese 436

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    <span class="mw-page-title-main">Gliese 581c</span> Super-Earth exoplanet orbiting Gliese 581

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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> Type of exoplanet

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    <span class="mw-page-title-main">Gliese 581e</span> Terrestrial planet orbiting Gliese 581

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    <span class="mw-page-title-main">Gliese 555</span> Star in the constellation Libra

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    References

    1. 1 2 Bonfils, Xavier; Forveille, Thierry; Delfosse, Xavier; Udry, Stéphane; Mayor, Michel; Perrier, Christian; Bouchy, François; Pepe, Francesco; Queloz, Didier; Bertaux, Jean-Loup (2005). "The HARPS search for southern extra-solar planets VI: A Neptune-mass planet around the nearby M dwarf Gl 581". Astronomy and Astrophysics. 443 (3): L15–L18. arXiv: astro-ph/0509211 . Bibcode:2005A&A...443L..15B. doi:10.1051/0004-6361:200500193. S2CID   59569803.
    2. 1 2 3 4 5 von Stauffenberg, A.; Trifonov, T.; Quirrenbach, A.; et al. (2024-06-05). "The CARMENES search for exoplanets around M dwarfs. Revisiting the GJ 581 multi-planetary system with new Doppler measurements from CARMENES, HARPS, and HIRES". Astronomy & Astrophysics. arXiv: 2407.11520 . doi:10.1051/0004-6361/202449375. ISSN   0004-6361.
    3. Robertson, Paul; Mahadevan, Suvrath; Endl, Michael; Roy, Arpita (3 July 2014). "Stellar activity masquerading as planets in the habitable zone of the M dwarf Gliese 581". Science . 345 (6195): 440–444. arXiv: 1407.1049 . Bibcode:2014Sci...345..440R. doi:10.1126/science.1253253. PMID   24993348. S2CID   206556796.
    4. M. Lopez-Morales; et al. (2006). "Limits to Transits of the Neptune-mass planet orbiting Gl 581". Publications of the Astronomical Society of the Pacific . 118 (849): 1506–1509. arXiv: astro-ph/0609255 . Bibcode:2006PASP..118.1506L. doi:10.1086/508904. S2CID   15156619.