Wolf 1069 b
{{Short description|Potentially habitable Earth-sized exoplanet}}
{{Infobox planet
| discoverer = Kossakowski et al.
| period = {{val|15.564|0.015|ul=day}}
| mean_radius = {{Val|1.08|ul=Earth radius}}
| name = Wolf 1069 b
| discovery_method = Radial velocity
| alt_names = LHS 3549 b, NLTT 49289 b, GJ 1253 b{{Cite web |title=⬤ Exoplanet Gliese 1253 b |url=https://www.stellarcatalog.com/exoplanet.php?planetID=101042 |access-date=2024-01-19 |website=Stellar Catalog |language=en}}
| extrasolarplanet = yes
| semimajor = {{val|0.0672|0.0014|ul=AU}}
| star = Wolf 1069
| mass = {{val|1.26|0.21|ul=Earth mass}}
| single_temperature = {{val|250.1|6.6|6.5|ul=K}} ({{val|-23|6.6|6.5|ul=°C}})
}}
Wolf 1069 b is an Earth-sized planet orbiting the red dwarf star Wolf 1069. Being located in the habitable zone of its star, Wolf 1069 b is considered a potentially habitable planet, as well as the sixth-closest Earth-mass planet orbiting within its star's habitable zone.{{Cite web |last=Anderson |first=Natali |date=2023-02-08 |title=Astronomers Discover Earth-Mass Exoplanet in Habitable Zone of Wolf 1069 |url=https://www.sci.news/astronomy/earth-mass-exoplanet-habitable-zone-wolf-1069-11636.html |access-date=2024-01-19 |website=Sci.News: Breaking Science News |language=en-US}} The minimum mass of the planet, as measured by the radial velocity method, is 1.26 {{Earth mass|link=Y}}, while its radius is estimated at 1.08 {{Earth radius|link=Y}}.{{Cite journal |last1=Kossakowski |first1=D. |last2=Kürster |first2=M. |last3=Trifonov |first3=T. |last4=Henning |first4=Th |last5=Kemmer |first5=J. |last6=Caballero |first6=J. A. |last7=Burn |first7=R. |last8=Sabotta |first8=S. |last9=Crouse |first9=J. S. |last10=Fauchez |first10=T. J. |last11=Nagel |first11=E. |last12=Kaminski |first12=A. |last13=Herrero |first13=E. |last14=Rodríguez |first14=E. |last15=González-Álvarez |first15=E. |date=2023-02-01 |title=The CARMENES search for exoplanets around M dwarfs - Wolf 1069 b: Earth-mass planet in the habitable zone of a nearby, very low-mass star |url=https://www.aanda.org/articles/aa/abs/2023/02/aa45322-22/aa45322-22.html |journal=Astronomy & Astrophysics |language=en |volume=670 |pages=A84 |doi=10.1051/0004-6361/202245322 |issn=0004-6361|arxiv=2301.02477 }} The equilibrium temperature of Wolf 1069 b is -23 °C.{{Cite web |last=Martin |first=Pierre-Yves |date=2023 |title=Planet Wolf 1069 b |url=https://exoplanet.eu/catalog/wolf_1069_b--8577/ |access-date=2024-01-19 |website=exoplanet.eu |language=en}}{{Cite web |title=Wolf 1069 {{!}} NASA Exoplanet Archive |url=https://exoplanetarchive.ipac.caltech.edu/overview/Wolf%201069 |access-date=2024-01-19 |website=exoplanetarchive.ipac.caltech.edu}}
Characteristics
Located about {{Convert|9.6|pc|ly}} from Earth, it is one of the closest known exoplanets. The minimum mass of Wolf 1069 b is measured at {{val|1.26|0.21|ul=Earth mass}}— very similar to that of Earth. Its radius is estimated at 1.08 {{Earth radius|link=y}} according to mass-radius relationships.
The planet takes about 16 days to fully orbit Wolf 1069, and is located at an average distance of {{convert|0.0672|AU|km|lk=in}} from it, which makes it located in its star's habitable zone.
Wolf 1069 b was discovered using radial velocity data from the CARMENES spectrograph at the Calar Alto Observatory, Spain.{{Cite web |last=Tognetti |first=Laurence |date=February 3, 2023 |title=Astronomers discover potential habitable exoplanet only 31 light-years from Earth |url=https://www.space.com/wolf-1069-b-exoplanet-habitable-earth-mass-discovery |access-date=2024-01-19 |website=Space.com |language=en}} Its discovery was announced in January 2023, in the journal Astronomy & Astrophyics.{{Cite web |last=Carter |first=Jamie |title=Found: An Earth-Mass Planet That's Potentially Habitable And Just 31 Light-Years Away |url=https://www.forbes.com/sites/jamiecartereurope/2023/02/03/found-an-earth-mass-planet-thats-potentially-habitable-and-just-31-light-years-away/ |access-date=2024-01-19 |website=Forbes |language=en}}
Habitability
Wolf 1069 b is considered a potentially habitable planet, as it orbits in the conservative habitable zone of its star (located between 0.056 and 0.111 astronomical units), in addition to having a mass similar to that of Earth. It is very likely that Wolf 1069 b has a similar composition to Earth (32.5% of iron and 67.5% of silicate), in addition to probably having liquid water on its surface. Located 31 light-years away, it is the sixth-closest Earth-mass planet orbiting in the habitable zone of its host star— only Gliese 1002 b and c, Gliese 1061 b, Teegarden b and Proxima Centauri b are closer. Its equilibrium temperature is calculated at {{convert|250|K|C}}, and it receives an incident flux from its star equivalent to 65% of what the Earth receives from the Sun.
Despite being considered potentially habitable, the short distance from its star causes Wolf 1069 b to be tidally locked, meaning one side of the planet is always facing its star, while the other is always opposite it. Because it is tidally locked, Wolf 1069 b does not have a day/night cycle like Earth, meaning that one side of the planet is in an eternal day while the other side is in an eternal night.
Host star
{{Main article|Wolf 1069}}
Wolf 1069 is a red dwarf that is located 31 light-years from Earth in the northern constellation Cygnus. The star has a slow rotation period, rotating on its own axis every 170 days, while the Sun takes 25 days to complete one rotation.{{Cite web |title=Sun Fact Sheet |url=https://nssdc.gsfc.nasa.gov/planetary/factsheet/sunfact.html |access-date=January 19, 2023 |website=nssdc.gsfc.nasa.gov}} Wolf 1069 is much smaller, cooler and less massive than the Sun, having a mass of 0.167 {{Solar mass|link=y}}, a surface temperature of {{Convert|3158|K|C}}, and a radius of 0.18 {{Solar radius|link=y}}, which makes it one of the smallest stars known. It was discovered in 1920 by Max Wolf.