Tau Ceti f

Last updated
Tau Ceti f
Discovery
Discovery dateDecember 19, 2012
Doppler spectroscopy
Orbital characteristics
1.334 au
Eccentricity 0.16
1.7 y
Star Tau Ceti
Physical characteristics
Mean radius
~1.81 R🜨 (estimate) [1]
Mass ≥3.93 M🜨

    Tau Ceti f is a potential super-Earth [2] or mini-Neptune orbiting Tau Ceti that was discovered in 2012 by statistical analyses of the star's variations in radial velocity, based on data obtained using HIRES, AAPS, and HARPS. It is of interest because its orbit places it in Tau Ceti's extended habitable zone, [3] [4] but a 2015 study implies that there may not be a detectable biosignature because it has only been in the temperate zone for less than one billion years. [5] [6] In 2017, it was again recovered from radial-velocity data, along with Tau Ceti e. Despite this, it remains an unconfirmed candidate. [7]

    Contents

    Characteristics

    Few properties of the planet are known other than its orbit and mass. It orbits Tau Ceti at a distance of 1.35 AU (roughly Mars's perihelion in the Solar System) with an orbital period of 642 days, and has a minimum mass of 3.93 Earth masses. [7] However, if it and its companion planets were similarly inclined to Tau Ceti's debris disk at 35±10°, f could 5.56+1.48
    −1.94     and 9.30+2.48
    −3.24     Earth masses, which means it's slightly more likely to be a mini-Neptune, although the exoplanet is included in the conservative sample of potentially habitable exoplanets. [8] It is estimated to be 1.81 Earth radii. [1]

    A 2021 study was unable to confirm this planet. [9]

    Habitability

    As of October 2020, Tau Ceti f is considered the most potentially habitable exoplanet orbiting a Sun-like star. [10] Its neighbor, Tau Ceti e, was previously regarded as a potentially habitable exoplanet in the conservative sample, but it was determined to likely be too hot to hold life, more similar to Venus. [11] It and its companion may suffer from a continuous bombardment of asteroids, up to 10 times higher than in the Solar System, [12] but a conjectured (super-)Jovian planet as outlined in a 2019 Astronomy & Astrophysics paper may be shepherding the disk, as it may be as close as 3 AU and as far away as 20. [13]

    With a flux of 0.32 the flux on Earth, Tau Ceti f has an estimated equilibrium temperature of only 190 Kelvin. If the conditions were the same as on the Earth, Tau Ceti f's average temperature would be around -50 °C. However, with a thicker atmosphere and a larger ocean, the temperature could be similar to Earth's. [14]

    See also

    Related Research Articles

    <span class="mw-page-title-main">Tau Ceti</span> Single yellow-hued star in the constellation Cetus

    Tau Ceti, Latinized from τ Ceti, is a single star in the constellation Cetus that is spectrally similar to the Sun, although it has only about 78% of the Sun's mass. At a distance of just under 12 light-years from the Solar System, it is a relatively nearby star and the closest solitary G-class star. The star appears stable, with little stellar variation, and is metal-deficient relative to the Sun.

    GJ 1061 is a red dwarf star located 12 light-years from Earth in the southern constellation of Horologium. Even though it is a relatively nearby star, it has an apparent visual magnitude of about 13, so it can only be seen with at least a moderately-sized telescope.

    HD 85512 is a solitary K-type main-sequence star 36.8 light-years away in the constellation Vela. It is about 1 billion years older than the Sun. It is extremely chromospherically inactive, only slightly more active than Tau Ceti. It exhibits a long-term variability and was thought to host one low-mass planet, although this is now doubtful.

    <span class="mw-page-title-main">HD 10180</span> Star in the constellation Hydrus

    HD 10180, also designated 2MASS J01375356-6030414, is a Sun-like star in the southern constellation Hydrus that is notable for its large planetary system. Since its discovery, at least six exoplanets have been observed orbiting it, and some studies have proposed up to nine potential planets, which would make it potentially the largest of all known planetary systems, including the Solar System.

    <span class="mw-page-title-main">HD 40307 g</span> Exoplanet candidate in the constellation of Pictor

    HD 40307 g is an exoplanet candidate suspected to be orbiting in the habitable zone of HD 40307. It is located 42 light-years away in the direction of the southern constellation Pictor. The planet was discovered by the radial velocity method, using the European Southern Observatory's HARPS apparatus by a team of astronomers led by Mikko Tuomi at the University of Hertfordshire and Guillem Anglada-Escude of the University of Göttingen, Germany.

    <span class="mw-page-title-main">Tau Ceti e</span> Super-Earth exoplanet orbiting Tau Ceti

    Tau Ceti e, also called 52 Ceti e, is an unconfirmed exoplanet candidate orbiting Tau Ceti, first detected in 2012 by statistical analyses of the star's variations in radial velocity obtained using HIRES, AAPS and HARPS. Its possible properties were refined in 2017, where it was one of two planets recovered from new data, the other being Tau Ceti f. It would orbit at a distance of 0.552 AU with an orbital period of 168 days and has a minimum mass of 3.93 Earth masses. If Tau Ceti e possesses an Earth-like atmosphere, the surface temperature would be around 68 °C. Based upon the incident flux upon the planet, a study by Güdel et al. (2014) speculated that the planet may lie inside the inner-boundary of the habitable zone and be a Venus-like world.

    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">TRAPPIST-1e</span> Earth-size exoplanet orbiting TRAPPIST-1

    TRAPPIST-1e, also designated as 2MASS J23062928-0502285 e, is a rocky, close-to-Earth-sized exoplanet orbiting within the habitable zone around the ultracool dwarf star TRAPPIST-1, located 40.7 light-years away from Earth in the constellation of Aquarius. Astronomers used the transit method to find the exoplanet, a method that measures the dimming of a star when a planet crosses in front of it.

    WASP-47 is a star similar in size and brightness to the Sun about 881 light-years away in the constellation Aquarius. It lies within the Kepler K2 campaign field 3. It was first noticed to have a hot Jupiter exoplanet orbiting every 4 days in 2012 by the Wide Angle Search for Planets (WASP) team. While it was thought to be a typical hot Jupiter system, three more planets were found in 2015: an outer gas giant within the habitable zone, a hot Neptune exterior to the hot Jupiter's orbit and a super-Earth interior to the hot Jupiter's orbit. WASP-47 is the only planetary system known to have both planets near the hot Jupiter and another planet much further out.

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

    Teegarden's Star b is an exoplanet found orbiting within the habitable zone of Teegarden's Star, an M-type red dwarf 12.5 light years away from the Solar System. It had the highest Earth Similarity Index (ESI) of any exoplanet, but in February 2024 a new study updated the parameters of the planet, thus reducing its ESI to 0.90, making it no longer the planet with the hightest ESI. Along with Teegarden's Star c, it is among the closest known potentially habitable exoplanets.

    <span class="mw-page-title-main">HD 189567</span> Star in the constellation Pavo

    HD 189567 is a star with a pair of orbiting exoplanets, located in the southern constellation of Pavo. It is also known as Gliese 776, CD-67 2385, and HR 7644. The star has an apparent visual magnitude of 6.07, which is bright enough for it to be dimly visible to the naked eye. It lies at a distance of 58 light years from the Sun based on parallax measurements, but is drifting closer with a radial velocity of −10.5 km/s.

    <span class="mw-page-title-main">Kepler-1638</span> G-type star in the constellation Cygnus

    Kepler-1638 is a G-type main-sequence star located about 5,000 light years away in the constellation of Cygnus. One known exoplanet has been found orbiting the star: Kepler-1638b.As of January 2021, Kepler-1638 is the farthest star with a known exoplanet orbiting in the habitable zone.

    GJ 1002 b is a potentially habitable exoplanet located 16 light-years away, in the constellation of Cetus. The planet, which has an Earth Similarity Index of 86%, is in the habitable zone of its parent star. GJ 1002 b has a minimum mass of 1.08 Earth masses and is estimated by the Planetary Habitability Laboratory to have 1.03 times the radius of Earth and a surface temperature of 261 Kelvin.

    References

    1. 1 2 "Exoplanet-catalog". Exoplanet Exploration: Planets Beyond our Solar System. Retrieved 2020-10-08.
    2. ↑ "Exoplanet-catalog". Exoplanet Exploration: Planets Beyond our Solar System. Retrieved 2020-10-14.
    3. ↑ "Two Nearby Habitable Worlds? - Planetary Habitability Laboratory @ UPR Arecibo". phl.upr.edu. Archived from the original on 2021-03-08. Retrieved 2020-10-07.
    4. ↑ "Four Exoplanets Detected around Nearby Star Tau Ceti | Astronomy | Sci-News.com". Breaking Science News | Sci-News.com. Retrieved 2020-10-07.
    5. ↑ April 2015, Mike Wall 24 (24 April 2015). "Nearby Alien Planets Not So Life-Friendly After All". Space.com. Retrieved 2020-10-07.{{cite web}}: CS1 maint: numeric names: authors list (link)
    6. ↑ Pagano, Michael; Truitt, Amanda; Young, Patrick A.; Shim, Sang-Heon (2015-04-21). "THE CHEMICAL COMPOSITION OF τ CETI AND POSSIBLE EFFECTS ON TERRESTRIAL PLANETS". The Astrophysical Journal. 803 (2): 90. arXiv: 1503.04189 . doi:10.1088/0004-637X/803/2/90. ISSN   1538-4357.
    7. 1 2 Feng, Fabo; Tuomi, Mikko; Jones, Hugh R. A.; Barnes, John; Anglada-Escude, Guillem; Vogt, Steven S.; Butler, R. Paul (2017-09-05). "Color difference makes a difference: four planet candidates around tau Ceti". The Astronomical Journal. 154 (4): 135. arXiv: 1708.02051 . Bibcode:2017AJ....154..135F. doi: 10.3847/1538-3881/aa83b4 . ISSN   1538-3881.
    8. ↑ "The Habitable Exoplanets Catalog - Planetary Habitability Laboratory @ UPR Arecibo". phl.upr.edu. Retrieved 2020-10-14.
    9. ↑ Cretignier, Michael; Dumusque, Xavier; et al. (September 2021). "YARARA: Significant improvement in RV precision through post-processing of spectral time series". Astronomy & Astrophysics . 653: A43. arXiv: 2106.07301 . Bibcode:2021A&A...653A..43C. doi:10.1051/0004-6361/202140986.
    10. ↑ "The Habitable Exoplanets Catalog - Planetary Habitability Laboratory @ UPR Arecibo". phl.upr.edu. Retrieved 2020-10-07.
    11. ↑ "Two Nearby Habitable Worlds? - Planetary Habitability Laboratory @ UPR Arecibo". sites.google.com. Retrieved 2020-10-08.
    12. ↑ "Death Down Asteroid Alley". Astrobiology Magazine. 2004-07-02. Archived from the original on 2004-08-29. Retrieved 2020-10-08.{{cite web}}: CS1 maint: unfit URL (link)
    13. ↑ Kervella, Pierre; Arenou, Frédéric; et al. (2019). "Stellar and substellar companions of nearby stars from Gaia DR2". Astronomy & Astrophysics. 623: A72. arXiv: 1811.08902 . Bibcode:2019A&A...623A..72K. doi:10.1051/0004-6361/201834371. ISSN   0004-6361. S2CID   119491061. We also detect the signature of a possible planet of a few Jovian masses orbiting τ Ceti…The observed signal could be explained for example, by a Jupiter analog orbiting at 5au.
    14. ↑ "Open Exoplanet Catalogue - tau Ceti f". openexoplanetcatalogue.com. Retrieved 2020-10-08.


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