Gliese 581b

Last updated
Gliese 581 b
Exoplanet Comparison Gliese 581 b.png
Size comparison of Gliese 581 b with Neptune.
(Based on selected hypothetical modeled compositions)
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]
0.041±0.001  AU
Eccentricity 0.022+0.027
−0.005
5.368±0.001  d
2454751.76 ± 0.01 [3]
118.3°+27.4°
−22.9°
Semi-amplitude 12.35+0.18
−0.20
  m/s
Star Gliese 581
Physical characteristics [2]
Mass ≥15.20+0.22
−0.27
  M🜨

    Gliese 581b or Gl 581b is an exoplanet orbiting within the Gliese 581 system. It is the first planet discovered of three confirmed in the system so far, and the second in order from the star. [4] [5]

    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 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 is at a minimum, approximately 15.8 times the Earth's mass, similar to Neptune's mass. It does not transit its star, implying that its inclination is less than 88.1 degrees. [6] It is rather close to Gliese 581 and completes a full orbit in only 5.4 days at a mean distance of about 6 million kilometers (0.041 AU). 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

    Related Research Articles

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

    Gliese 876 is a red dwarf approximately 15 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 Gliese 1061, YZ Ceti, Tau Ceti, and Luyten's Star; 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

    Gliese 436 is a red dwarf located 31.9 light-years away in the zodiac constellation of Leo. It has an apparent visual magnitude of 10.67, which is much too faint to be seen with the naked eye. However, it can be viewed with even a modest telescope of 2.4 in (6 cm) aperture. In 2004, the existence of an extrasolar planet, Gliese 436 b, was verified as orbiting the star. This planet was later discovered to transit its host star.

    Gliese 581 is a red dwarf star of spectral type M3V at the center of the Gliese 581 planetary system, about 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

    Gliese 436 b is a Neptune-sized exoplanet orbiting the red dwarf Gliese 436. It was the first hot Neptune discovered with certainty and was among the smallest-known transiting planets in mass and radius, until the much smaller Kepler exoplanet discoveries began circa 2010.

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

    Gliese 581c is an exoplanet orbiting within the Gliese 581 system. It is the second planet discovered in the system and the third in order from the star. With a mass at least 5.5 times that of the Earth, it is classified as a super-Earth.

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

    Gliese 581d was a candidate extrasolar planet orbiting within the Gliese 581 system, approximately 20.4 light-years away in the Libra constellation. It was the third planet claimed in the system and the fourth or fifth in order from the star. Multiple subsequent studies found that the planetary signal in fact originates from stellar activity, and thus the planet does not exist.

    <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.

    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 832 is a red dwarf of spectral type M2V in the southern constellation Grus. The apparent visual magnitude of 8.66 means that it is too faint to be seen with the naked eye. It is located relatively close to the Sun, at a distance of 16.2 light years and has a high proper motion of 818.16 milliarcseconds per year. Gliese 832 has just under half the mass and radius of the Sun. Its estimated rotation period is a relatively leisurely 46 days. The star is roughly 6 billion years old.

    Gliese 832 b is a gas giant exoplanet about 80% the mass of Jupiter, located 16.2 light-years from the Sun in the constellation of Grus, orbiting the red dwarf star Gliese 832.

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

    Gliese 581e or Gl 581e is an exoplanet orbiting within the Gliese 581 system, located approximately 20.4 light-years away from Earth in the Libra constellation. It is the third planet discovered in the system and the first in order from the star.

    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.

    <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 July 2023, there are 5,425 confirmed exoplanets in 4,001 planetary systems, with 868 systems having more than one planet. This is a list of the most notable discoveries.

    <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.

    Gliese 15 Ab, also commonly called Groombridge 34 Ab, is an extrasolar planet approximately 11 light-years away in the constellation of Andromeda. It is found in the night sky orbiting the star Gliese 15 A, which is at right ascension 00h 18m 22.89s and declination +44° 01′ 22.6″.

    GJ 3470 is a red dwarf star located in the constellation of Cancer, 96 light-years away from Earth. With a faint apparent magnitude of 12.3, it is not visible to the naked eye. It hosts one known exoplanet.

    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 Trifonov, T.; Kürster, M.; et al. (February 2018). "The CARMENES search for exoplanets around M dwarfs. First visual-channel radial-velocity measurements and orbital parameter updates of seven M-dwarf planetary systems". Astronomy & Astrophysics . 609: A117. arXiv: 1710.01595 . Bibcode:2018A&A...609A.117T. doi:10.1051/0004-6361/201731442.
    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. "Gl 581 b". Archived from the original on 2014-02-10.
    5. "If There's Life on Alien Planet Gliese 581g, How Do We Find It?". Space.com . 30 September 2010.
    6. 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.