HD 40307

Last updated
HD 40307
Location of HD 40307.png
Location of HD 40307 in the night sky. The star is marked within the red diamond below the word "Pictor".
Observation data
Epoch J2000.0        Equinox J2000.0 (ICRS)
Constellation Pictor
Right ascension 05h 54m 04.24050s [1]
Declination −60° 01′ 24.4930″ [1]
Apparent magnitude  (V)7.17 [2]
Characteristics
Spectral type K2.5V [2]
B−V color index 0.93 [2]
Astrometry
Radial velocity (Rv)31.08±0.12 [1]  km/s
Proper motion (μ)RA: −52.174±0.023  mas/yr [1]
Dec.: −60.059±0.025  mas/yr [1]
Parallax (π)77.3261 ± 0.0170  mas [1]
Distance 42.179 ± 0.009  ly
(12.932 ± 0.003  pc)
Absolute magnitude  (MV)6.57±0.01 [3]
Details
Mass 0.75+0.03
−0.04 [4]   M☉
Radius 0.716 ± 0.010 [5]   R☉
Luminosity (bolometric)0.23 [6]   L☉
Luminosity (visual, LV)0.20 [note 1]   L☉
Surface gravity (log g)4.47 ± 0.16 [6]   cgs
Temperature 4977 ± 59 [6]   K
Metallicity [Fe/H]−0.31 ± 0.03 [6]   dex
Rotation 31.8±6.7 d [7]
Rotational velocity (v sin i)3 [4]  km/s
Age 1.2 (≥ 0.2) [4]   Gyr
Other designations
CD−60 1303, CPD−60 508, GC  7474, GJ  2046, HIP  27887, PPM  355061, SAO  249388, 2MASS J05540421-6001245. [2]
Database references
SIMBAD data
Exoplanet Archive data
ARICNS data
Extrasolar Planets
Encyclopaedia 		data

HD 40307 is an orange (K-type) main-sequence star located approximately 42 light-years away in the constellation of Pictor (the Easel), taking its primary name from its Henry Draper Catalogue designation. It is calculated to be slightly less massive than the Sun. The star has six known planets, three discovered in 2008 [2] [8] and three more in 2012. One of them, HD 40307 g, is a potential super-Earth in the habitable zone, with an orbital period of about 200 days. This object might be capable of supporting liquid water on its surface, although much more information must be acquired before its habitability can be assessed. [9] [10] [11] [12]

Contents

No stellar companions to HD 40307 were detected as in 2018. [13]

History and nomenclature

HD 40307 was observed during or before 1900 as part of the Cape Photographic Durchmusterung. [14] The designation HD 40307 is from the Henry Draper Catalogue, which is based on spectral classifications made between 1911 and 1915 by Annie Jump Cannon and her co-workers, and was published between 1918 and 1924. [15] [16]

Characteristics

As a K-type star, HD 40307 emits orange-tinted light. [2] It has only about three-quarters of the Sun's radius and mass. [4] Its temperature is measured at slightly under 5,000  K .

The astronomers who discovered the planets orbiting HD 40307 suggested that the metallicities of stars determine whether or not the planetary bodies that orbit them will be terrestrial, like Earth, or gaseous, like Jupiter and Saturn. [6]

Distance and visibility

Despite its relative proximity to the Sun at 42 light-years, HD 40307 is not visible to the naked eye, given its apparent magnitude of 7.17. [17] It came within 6.4 light-years of the Sun about 413,000 years ago. [18]

Planetary system

A planetary system around HD 40307 contains four confirmed planets and two other possible planets, all within 0.6  AU of the star.

The HD 40307 planetary system [10] [19] [20]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b ≥ 4.0 +0.8
−0.7  M🜨 		0.0468 +0.0023
−0.0024		4.3123 +0.0011
−0.0012		0.20 +0.16
−0.14		>0.2022° —
c ≥ 6.6 +1.1
−1.0  M🜨 		0.0799 ± 0.00409.6184 +0.0050
−0.0049		0.06 +0.06
−0.11		>0.2109° —
d ≥ 9.5 +1.7
−1.5  M🜨 		0.1321 +0.0066
−0.0064		20.432 +0.022
−0.024		0.07 +0.11
−0.07		>0.2855° —
e (disputed)≥ 3.5 ± 1.4 M🜨 0.1886 +0.083
−0.0104		34.62 +0.21
−0.20		0.15 +0.13
−0.15		——
f ≥ 5.2 +1.5
−1.6  M🜨 		0.247 +0.011
−0.014		51.76 +0.50
−0.46		0.02 +0.20
−0.02		——
g (disputed)≥ 7.1 ± 2.6 M🜨 0.600 +0.034
−0.033		197.8 +9.0
−5.7		0.29 +0.31
−0.29		——
The orbits of the inner three planets of HD 40307. HD40307.svg
The orbits of the inner three planets of HD 40307.

After spending five years observing the star, [21] the European Organisation for Astronomical Research in the Southern Hemisphere (ESO) announced that they had discovered three super-Earths in orbit around HD 40307 in June 2008. All three planets were detected by the radial velocity method, using the HARPS spectrograph system. [22]

In 2012, an independent analysis carried out by a team of astronomers led by Mikko Tuomi of the University of Hertfordshire confirmed the existence of these planets and found an additional three planets in the systems. [9] [10] The planet HD 40307 f on 51.6-day orbit was confirmed in 2015, with inconclusive evidence for the planets HD 40307 e and HD 40307 g. [19]

Five of the planets orbit very close to the star, [10] with the farthest of them located twice as close to HD 40307 than is the planet Mercury is to the Sun. [23] [note 2] The outermost planet orbits at a distance similar to the distance of Venus to the Sun and is situated well in the system's liquid water habitable zone. [10]

The minimum masses of the planets in the system ranges from three to ten times the mass of the Earth, placing them somewhere between Earth and gas giants like Uranus and Neptune. [10] Dynamical analysis of the innermost planets suggests that planet b is unstable at its age unless it is an ice giant, having migrated from further away. That implies similar for the other planets, even further out. [24] The most recent discovery also indicates via dynamical analysis that the true planetary masses can not be much higher than their minimum masses. [10]

See also

Notes

  1. ↑ Using the absolute visual magnitude of HD 40307 and the absolute visual magnitude of the Sun , the visual luminosity can be calculated by
  2. ↑ Mercury orbits at approx. 0.39 AU

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HD 40307 b is an extrasolar planet orbiting the star HD 40307, 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, in June 2008. It is the second smallest of the planets orbiting the star, after HD 40307 e. The planet is of interest as this star has relatively low metallicity, supporting a hypothesis that different metallicities in protostars determine what kind of planets they will form.

HD 40307 c is an extrasolar planet orbiting the star HD 40307, located 42 light-years away in the direction of the southern constellation Pictor. The planet was discovered by the radial velocity method, using the HARPS apparatus, in June 2008. Of the six proposed planets in the HD 40307 star system, it is the third-largest, and has the second-closest orbit from the star. The planet is of interest as this star has relatively low metallicity, supporting a hypothesis that different metallicities in protostars determine what kind of planets they will form.

HD 40307 d is an extrasolar planet orbiting the star HD 40307, located 42 light-years from Earth in the direction of the southern constellation Pictor. The planet was discovered by the radial velocity method, using the HARPS apparatus in June 2008. It is the most massive of the six proposed planets in the system. The planet is of interest as this star has relatively low metallicity, supporting a hypothesis that different metallicities in protostars determine what kind of planets they will form.

HD 47186 is a star located approximately 129 light-years away in the constellation of Canis Major. It is a G6V star with the characteristics very similar to the Sun, but it is 1.7 times more metal-rich. In 2008, two extrasolar planets were discovered orbiting the star.

HD 45364 is a star in the southern constellation of Canis Major. It is too faint to be visible to the naked eye, having an apparent visual magnitude of 8.08. The distance to this system is 112 light years based on parallax. It is drifting further away from the Sun with a radial velocity of +16.4 km/s, having come within 49 light-years some 1.5 million years ago.

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

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HD 38858 is a G-type star, much like The Sun, with one detected planet. The planet, designated HD 38858 b, is about twice the mass of Uranus and orbits in the star's habitable zone.

<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.

HD 40307 e is an extrasolar planet candidate suspected to be orbiting the star 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.

HD 40307 f is an extrasolar planet orbiting the star 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. The existence of planet was confirmed in 2015.

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.

HD 189567 is a G3V star located 58.5 light years away, in the constellation of Pavo. The star HD 189567 is also known as Gliese 776, CD-67 2385, and HR 7644.

References

  1. 1 2 3 4 5 6 Vallenari, A.; et al. (Gaia Collaboration) (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics . arXiv: 2208.00211 . doi: 10.1051/0004-6361/202243940 . Gaia DR3 record for this source at VizieR.
  2. 1 2 3 4 5 6 HD 40307, entry, SIMBAD. Accessed online June 18, 2008.
  3. ↑ Holmberg, J.; et al. (July 2009). "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics". Astronomy and Astrophysics. 501 (3): 941–947. arXiv: 0811.3982 . Bibcode:2009A&A...501..941H. doi:10.1051/0004-6361/200811191. S2CID   118577511. VizieR
  4. 1 2 3 4 HD 40307, database entry, Geneva-Copenhagen Survey of Solar neighbourhood, J. Holmberg et al., 2007, CDS database V/117A, accessed November 19, 2008; described in The Geneva-Copenhagen survey of the Solar neighbourhood. Ages, metallicities, and kinematic properties of ~14 000 F and G dwarfs, B. Nordström, M. Mayor, J. Andersen, J. Holmberg, F. Pont, B. R. Jørgensen, E. H. Olsen, S. Udry, and N. Mowlavi, Astronomy and Astrophysics 418 (May 2004), pp. 989–1019, Bibcode:2004A&A...418..989N, doi:10.1051/0004-6361:20035959.
  5. ↑ HD 40307, entry, CDS database J/A+A/450/735; described in Effective temperature scale and bolometric corrections from 2MASS photometry, E. Masana, C. Jordi, and I. Ribas, Astronomy and Astrophysics450, #2 (May 2006), pp. 735–746. Bibcode:2006A&A...450..735M. doi:10.1051/0004-6361:20054021.
  6. 1 2 3 4 5 M. Mayor; S. Udry; C. Lovis; F. Pepe; D. Queloz; W. Benz; J.-L. Bertaux; et al. (2009). "The HARPS search for southern extra-solar planets. XIII. A planetary system with 3 Super-Earths (4.2, 6.9, & 9.2 Earth masses)". Astronomy and Astrophysics . 493 (2): 639–644. arXiv: 0806.4587 . Bibcode:2009A&A...493..639M. doi:10.1051/0004-6361:200810451. S2CID   116365802.
  7. ↑ Suárez Mascareño, A.; et al. (September 2015). "Rotation periods of late-type dwarf stars from time series high-resolution spectroscopy of chromospheric indicators". Monthly Notices of the Royal Astronomical Society. 452 (3): 2745–2756. arXiv: 1506.08039 . Bibcode:2015MNRAS.452.2745S. doi:10.1093/mnras/stv1441.
  8. ↑ Jeanna Bryner (June 16, 2008). "Three super-Earths found around one star". NBC News. Retrieved June 18, 2008.
  9. 1 2 Amina Khan (November 7, 2012). "Possible Earth-like planet could hold water; scientists cautious". Los Angeles Times. Retrieved November 8, 2012.
  10. 1 2 3 4 5 6 7 Tuomi, Mikko; Anglada-Escudé, Guillem; Gerlach, Enrico; Jones, Hugh R. A.; Reiners, Ansgar; Rivera, Eugenio J.; Vogt, Steven S.; Butler, R. Paul (17 December 2012). "Habitable-zone super-Earth candidate in a six-planet system around the K2.5V star HD 40307". Astronomy & Astrophysics. 549: A48. arXiv: 1211.1617 . Bibcode:2013A&A...549A..48T. doi:10.1051/0004-6361/201220268. S2CID   7424216.
  11. ↑ Wall, Mike (November 7, 2012). "'Super-Earth' Alien Planet May Be Habitable for Life". Space.com . Retrieved November 8, 2012.
  12. ↑ Tate, Karl (November 7, 2012). "Super-Earth Planet: Potentially Habitable Alien World Explained (Infographic)". Space.com . Retrieved November 8, 2012.
  13. ↑ Dietrich, J.; Ginski, C. (2018). "Archival VLT/Na Co multiplicity investigation of exoplanet host stars". Astronomy & Astrophysics. 620: A102. arXiv: 1811.09666 . Bibcode:2018A&A...620A.102D. doi:10.1051/0004-6361/201731341. S2CID   119294338.
  14. ↑ CPD−60 508, database entry, Cape Photographic Durchmusterung (CPD), D. Gill and J. C. Kapetyn, 1895–1900, CDS ID I/108.
  15. ↑ pp. 214–215 in The Henry Draper Memorial, Annie J. Cannon, Journal of the Royal Astronomical Society of Canada9, #5 (May–June 1915), pp. 203–215, Bibcode : 1915JRASC...9..203C.
  16. ↑ The Henry Draper Catalogue, Annie J. Cannon and Edward C. Pickering, Annals of Harvard College Observatory;
    hours 0 to 3, 91 (1918), Bibcode : 1918AnHar..91....1C;
    hours 4 to 6, 92 (1918), Bibcode : 1918AnHar..92....1C;
    hours 7 to 8, 93 (1919), Bibcode : 1919AnHar..93....1C;
    hours 9 to 11, 94 (1919), Bibcode : 1919AnHar..94....1C;
    hours 12 to 14, 95 (1920), Bibcode : 1920AnHar..95....1C;
    hours 15 to 16, 96 (1921), Bibcode : 1921AnHar..96....1C;
    hours 17 to 18, 97 (1922), Bibcode : 1922AnHar..97....1C;
    hours 19 to 20, 98 (1923), Bibcode : 1923AnHar..98....1C;
    hours 21 to 23, 99 (1924), Bibcode : 1924AnHar..99....1C.
  17. ↑ "Stellar Magnitudes". Astrophysics 162 Unit. University of Tennessee. 2008. Retrieved 20 November 2008.
  18. ↑ Bobylev, Vadim V. (March 2010). "Searching for Stars Closely Encountering with the Solar System". Astronomy Letters. 36 (3): 220–226. arXiv: 1003.2160 . Bibcode:2010AstL...36..220B. doi:10.1134/S1063773710030060. S2CID   118374161.
  19. 1 2 Díaz, R. F.; et al. (2016). "The HARPS search for southern extra-solar planets. XXXVIII. Bayesian re-analysis of three systems. New super-Earths, unconfirmed signals, and magnetic cycles". Astronomy and Astrophysics. 585. A134. arXiv: 1510.06446 . Bibcode:2016A&A...585A.134D. doi:10.1051/0004-6361/201526729. S2CID   118531921.
  20. ↑ Kiefer, F.; Hébrard, G.; Lecavelier Des Etangs, A.; Martioli, E.; Dalal, S.; Vidal-Madjar, A. (2021). "Determining the true mass of radial-velocity exoplanets with Gaia". Astronomy & Astrophysics. 645: A7. arXiv: 2009.14164 . doi:10.1051/0004-6361/202039168. S2CID   221995447.
  21. ↑ "HD 40307 / CD-60 1303". SolStation. Sol Company. 2008. Retrieved 27 November 2008.
  22. ↑ Mayor; et al. (2008-06-16). "Trio of 'super-Earths' discovered". BBC News. Retrieved 2008-06-16.
  23. ↑ "Mercury Fact Sheet". NASA Goddard Space Flight Center. November 30, 2007. Retrieved 2008-11-12.
  24. ↑ Barnes, Rory; Jackson, Brian; Raymond, Sean N.; West, Andrew A.; Greenberg, Richard (January 13, 2009). "The HD 40307 Planetary System: Super-Earths or Mini-Neptunes?". The Astrophysical Journal. 695 (2): 1006–1011. arXiv: 0901.1698 . Bibcode:2009ApJ...695.1006B. doi:10.1088/0004-637X/695/2/1006. S2CID   18849636.

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