CoRoT-7
{{Short description|Star in the constellation Monoceros}}
{{Starbox begin
| name = CoRoT-7
}}
{{Starbox observe 2s
| epoch = J2000
| constell = Monoceros
| component1 = A
| dec1 = {{DEC|−01|03|46.817}}
| component2 = B
| dec2 = {{DEC|−01|03|49.427}}
| appmag_v2 =
}}
{{Starbox character
|component1=CoRoT-7A
|component2=CoRoT-7B
| type = main sequence
| type2 =
| b-v =
| u-b =
| variable =
}}
{{Starbox astrometry
| component1 = A
| radial_v = {{val|+31.174|0.0086}}
| parallax = 6.2676
| p_error = 0.0139
| component2 = B
| radial_v2 =
| parallax2 = 6.1353
| p_error2 = 0.1028
| absmag_v2 =
}}
{{Starbox relpos
| epoch = 2021
| primary = CoRoT-7A
| component = CoRoT-7B
| angdistsec = 75.7
| projsep = 12160
}}
{{Starbox detail
|component1=CoRoT-7A
|component2=CoRoT-7B
| temperature = {{val|fmt=commas|5250|60}}
| metal_fe = {{val|0.12|0.06}}
| rotation = ~23 days{{cite journal |author1=Queloz, D. |author2=Bouchy, F. |author3=Moutou, C. |author4=Hatzes, A. |author5=Hebrard, G. |year=2009 |title=The CoRoT-7 planetary system: two orbiting Super-Earths |url=http://www.aanda.org/articles/aa/pdf/forth/aa13096-09.pdf |journal=Astronomy and Astrophysics |doi=10.1051/0004-6361/200913096 |volume=506 |issue=1 |pages=303 |bibcode=2009A&A...506..303Q |display-authors=etal |doi-access=free }} Also available from [http://exoplanet.eu/papers/corot7-RV.pdf exoplanet.eu] {{Webarchive|url=https://web.archive.org/web/20120111055444/http://exoplanet.eu/papers/corot7-RV.pdf |date=2012-01-11 }}
}}
{{Starbox catalog
| names = 2MASS J06434947-0103468, TYC 4799-1733-1, GSC 04799-01733
| component1 = CoRoT-7A
| names1 = Gaia DR3 3107267177757848576
| component2 = CoRoT-7B
| names2 = Gaia DR3 3107267212116737792
}}
{{Starbox reference
| Simbad = TYC+4799-1733-1
| EPE = CoRoT-7
| NSTED = CoRoT-7
}}
{{Starbox end}}
{{Sky|06|43|49.0|-|01|03|46.0|489}}
CoRoT-7 (TYC 4799-1733-1) is a binary star system made up of a late G-type star and a M-dwarf star that was discovered in 2021. The primary star has three exoplanets,{{Cite web |title=CoRoT-7 Overview |url=https://exoplanetarchive.ipac.caltech.edu/overview/CoRoT-7%20b#planet_CoRoT-7-b_collapsible |access-date=February 18, 2024 |website=NASA Exoplanet Archive}} including CoRoT-7b, a super-Earth exoplanet that is remarkable due to its extremely high temperature (around 2000{{Nbsp}}°C) and very short orbital period, around 20 hours.{{Cite web |title=COROT discovers smallest exoplanet yet, with a surface to walk on |url=https://www.esa.int/Science_Exploration/Space_Science/COROT/COROT_discovers_smallest_exoplanet_yet_with_a_surface_to_walk_on |access-date=2024-02-18 |website=www.esa.int |language=en}}{{Cite web |last=Gregersen |first=Erik |title=CoRoT-7b |url=https://www.britannica.com/place/CoRoT-7b |access-date=2024-02-18 |website=Britannica |language=en}} It was the first exoplanet shown to be rocky.{{Cite web |last= |date=September 16, 2009 |title=First Solid Evidence for a Rocky Exoplanet - Mass and density of smallest exoplanet finally measured |url=https://www.eso.org/public/news/eso0933/ |access-date=February 18, 2024 |website=ESO |language=en}} The system has the name CoRoT-7 after the CoRoT space telescope, which discovered the exoplanets around the star CoRoT-7A. The stellar system is 520 light-years from the Earth.
Stellar components
= CoRoT-7A =
The primary, CoRoT-7A is a G-type main sequence star, slightly smaller, cooler, and younger than the Sun. It has an apparent magnitude of 11.67, fainter than Proxima Centauri (mag. 11.05), the nearest star to the Sun, and is far too faint to be seen with the naked eye. This star is approximately 520 light-years away from the Solar System in the constellation Monoceros (the Unicorn).{{cite web
| title=CoRoT-exo-7b Has CoRoT discovered the first transiting Super-Earth around a main sequence star?
| author=Rouan
| url=http://www.colloquium.eu/congres/09COROT/docs/slides/03mardi/11h/d_rouan/alancer.pdf
| publisher=CoRoT Symposium—Paris
| date=February 3, 2009
| accessdate=2009-07-05
| display-authors=etal
| url-status=dead
| archiveurl=https://web.archive.org/web/20110720154622/http://www.colloquium.eu/congres/09COROT/docs/slides/03mardi/11h/d_rouan/alancer.pdf
| archivedate=July 20, 2011
}}
= CoRoT-7B =
Location and properties
The star is located in the LRa01 field of view of the CoRoT spacecraft. It is about 500 light years from Earth. According to the project website, this field is in the Monoceros constellation. Published data{{Cite journal | arxiv=1005.3208 | author1=Bruntt | author2=Deleuil | author3=Fridlund | author4=Alonso | author5=Bouchy | author6=Hatzes | author7=Mayor | author8=Moutou | author9=Queloz | title=Improved stellar parameters of CoRoT-7 | year=2010 | doi=10.1051/0004-6361/201014143 | volume=519 | journal=Astronomy and Astrophysics | page=A51 | bibcode=2010A&A...519A..51B| s2cid=54657440 }} lists the stellar properties as being a G9V yellow dwarf with a temperature of 5250 K, a radius of about 82% of the Sun and a mass of about 91% of the Sun, But other sources have listed it as a (K0V) orange dwarf.{{cite encyclopedia |title=Star : CoRoT-7 |author=Jean Schneider |url=http://exoplanet.eu/star.php?st=CoRoT-7 |archive-url=https://web.archive.org/web/20090819030033/http://exoplanet.eu/star.php?st=CoRoT-7 |url-status=dead |archive-date=August 19, 2009 |encyclopedia=Extrasolar Planets Encyclopaedia |access-date=2009-12-26}} The metallicity is 0.12 ± 0.06. The star is estimated to be about 150 parsecs away and with an age in the range 1.2 – 2.3 billion years, is younger than our own star which has an age of 4.6 billion years. The rotation period of the star, inferred by the light curve obtained by CoRoT, is around 23 days.
Planetary system
The primary star is orbited by the super-Earth exoplanets CoRoT-7b and CoRoT-7c, both discovered in 2009. A third planet CoRoT-7d, initially proposed in a 2010 study,{{Cite journal | arxiv=1006.5476 | author1=Hatzes | author2=Dvorak | author3=Wuchterl | author4=Guterman | author5=Hartmann | author6=Fridlund | author7=Gandolfi | author8=Guenther | author9=Paetzold | title=An Investigation into the Radial Velocity Variations of CoRoT-7 | year=2010 | doi=10.1051/0004-6361/201014795 | volume=520 | journal=Astronomy and Astrophysics | page=A93 | bibcode=2010A&A...520A..93H| s2cid=38803450 }} was confirmed in 2022. The discovery of the inner planet was made using the transit method by the CoRoT program. CoRoT-7b is notable for its relatively small size, compared to other exoplanets known at the time.{{cite web
| url= http://www.obspm.fr/actual/nouvelle/feb09/exo7.en.shtml
| title= Super-Earth found! The smallest transiting extrasolar planet ever discovered
| accessdate= 2009-02-04
| date= February 2009
| publisher= Paris Observatory
| url-status= dead
| archiveurl= https://web.archive.org/web/20090923014043/http://www.obspm.fr/actual/nouvelle/feb09/exo7.en.shtml
| archivedate= 2009-09-23
}}
{{OrbitboxPlanet begin
}}
{{OrbitboxPlanet
| exoplanet = b
| mass_earth = {{val|6.056|0.653}}
| radius_earth = {{val|1.528|0.065}}
| period = {{val|0.853592|0.000000587}}
| semimajor = 0.0172 ± 0.00029
| eccentricity = 0
| inclination = {{val|80.98|0.51}}
}}
{{OrbitboxPlanet
| exoplanet = c
| mass_earth = {{val|13.289|0.689}}
| period = {{val|3.697|0.005}}
| semimajor = 0.046
| eccentricity = 0
}}
{{OrbitboxPlanet
| exoplanet = d
| mass_earth = {{val|17.142|2.552}}
| period = {{val|8.966|1.546}}
| semimajor = 0.08
| eccentricity = 0
}}
{{Orbitbox end}}
Because of the large difference in brightness between them and their parent star, these exoplanets cannot be seen in a telescope; only their gravitational effect can be detected by the Doppler effect on the star's electromagnetic spectrum (radial velocity method), as well as transits of planet b. This star was reported to have stellar activity, making the confirmation process for CoRoT-7b more difficult. In fact, mass estimates are affected by large uncertainty due to stellar activity that perturbs the radial velocity measurements needed to "weigh" the planets.{{cite web
| title=CoRoT-Exo-7b: Confirming the first transiting rocky planet
| url=http://ssc.spitzer.caltech.edu/warmmission/scheduling/approvedprograms/ddt/534.txt
| accessdate=2010-08-23
| archive-date=2011-09-29
| archive-url=https://web.archive.org/web/20110929074324/http://ssc.spitzer.caltech.edu/warmmission/scheduling/approvedprograms/ddt/534.txt
| url-status=dead
CoRoT-7d was first proposed by A. P. Hatzes et al. in 2010 by the radial velocity method. The existence of CoRoT-7d was disputed by a 2014 study, which concluded that the radial velocity signal was more likely to be an artifact of the stellar rotation. However, a 2022 study provided strong evidence for the existence of this planet, and it is now listed as a confirmed planet in the NASA Exoplanet Archive.{{cite web |title=CoRoT-7 |url=https://exoplanetarchive.ipac.caltech.edu/overview/CoRoT-7 |website=NASA Exoplanet Archive |accessdate=31 July 2022}} CoRoT-7d's mass is 17.1 times that of Earth, but its volume and diameter are unknown. One year on CoRoT-7d would be equivalent to 8.966 days on Earth.
References
{{Reflist|refs=
{{cite Gaia DR3|3107267177757848576}}
{{cite Gaia DR3|3107267212116737792}}
{{cite journal |last1=Haywood |first1=R. D. |display-authors=etal |title=Planets and stellar activity: hide and seek in the CoRoT-7 system |journal=Monthly Notices of the Royal Astronomical Society |date=September 2014 |volume=443 |issue=3 |pages=2517–2531 |doi=10.1093/mnras/stu1320 |doi-access=free |arxiv=1407.1044 |bibcode=2014MNRAS.443.2517H|s2cid=23807689 }}
}}
External links
- {{cite web|url= http://www.skyandtelescope.com/news/38820797.html|title= CoRoT Finds the Smallest Exoplanet Yet|accessdate= 2009-02-04|last= Schilling|first= Govert|date= 2009-02-03|publisher= Sky & Telescope|archive-url= https://web.archive.org/web/20090207054710/http://www.skyandtelescope.com/news/38820797.html|archive-date= 2009-02-07|url-status= dead}}
{{Stars of Monoceros}}
{{CoRoT-7}}
{{DEFAULTSORT:CoRoT-7}}
Category:G-type main-sequence stars
Category:M-type main-sequence stars
Category:Planetary transit variables