KOI-4878.01
{{Short description|Unconfirmed potentially habitable exoplanet}}
{{Infobox planet
| name = KOI-4878.01
| image = PlanetaSH(4).jpg
| caption = Artist's impression of KOI-4878.01
| discovery_site = Kepler space telescope
| discovered = 2015
| discovery_method = Transit
| apsis = astron
| semimajor = {{val|1.1392|0.0265|0.0268}} AU
| period = {{val|449.015|0.021}} days
| star = KOI-4878
| mean_radius = {{val|1.02|0.04|0.13|ul=Earth radius}}
| single_temperature = {{convert|257|K|C F}}
}}
KOI-4878.01 is an exoplanet candidate that orbits the G-type main-sequence star KOI-4878. It is {{convert|344|pc|ly|order=flip}} distant from Earth.{{cite Exoplanet Archive|KOI-4878}} The features of the planet are very similar to that of Earth, and if it is confirmed, it would be one of the most Earth-like planets found. The orbital period of the exoplanet is around 449 days. It is located within the habitable zone of its parent star{{snd}}a region where water can exist at liquid state.
Host star
KOI-4878 is a G-type main-sequence star, more precisely of spectral class G4V.{{Cite journal |last1=Frasca |first1=A. |last2=Molenda-Żakowicz |first2=J. |last3=De Cat |first3=P. |last4=Catanzaro |first4=G. |last5=Fu |first5=J. N. |last6=Ren |first6=A. B. |last7=Luo |first7=A. L. |last8=Shi |first8=J. R. |last9=Wu |first9=Y. |last10=Zhang |first10=H. T. |date=October 2016 |title=Activity indicators and stellar parameters of the Kepler targets. An application of the ROTFIT pipeline to LAMOST-Kepler stellar spectra |bibcode=2016A&A...594A..39F |journal=Astronomy and Astrophysics |language=en |volume=594 |pages=A39 |doi=10.1051/0004-6361/201628337 |arxiv=1606.09149 |issn=0004-6361}} It has an apparent magnitude of 12.37 and is located in the constellation of Draco.{{cite constellation|KOI-4878}} The star has a mass of {{val|1.009|0.129|ul=solar mass}}, a radius of {{val|1.131|0.059|ul=solar radius}} and an effective temperature of {{val|5674|125|ul=K}}.{{Cite journal |last1=Stassun |first1=Keivan G. |last2=Oelkers |first2=Ryan J. |last3=Paegert |first3=Martin |last4=Torres |first4=Guillermo |last5=Pepper |first5=Joshua |last6=De Lee |first6=Nathan |last7=Collins |first7=Kevin |last8=Latham |first8=David W. |last9=Muirhead |first9=Philip S. |last10=Chittidi |first10=Jay |last11=Rojas-Ayala |first11=Bárbara |last12=Fleming |first12=Scott W. |last13=Rose |first13=Mark E. |last14=Tenenbaum |first14=Peter |last15=Ting |first15=Eric B. |date=2019-10-01 |title=The Revised TESS Input Catalog and Candidate Target List |journal=The Astronomical Journal |volume=158 |issue=4 |pages=138 |doi=10.3847/1538-3881/ab3467 |doi-access=free |arxiv=1905.10694 |bibcode=2019AJ....158..138S |issn=0004-6256}} [https://vizier.cds.unistra.fr/viz-bin/VizieR?-source=IV/38&TIC=405717775 KOI-4878's database entry] at VizieR. Its age is estimated at {{val|6.1|2.5}} billion years, older than the Solar System.
Exoplanet detection
An analysis of the Kepler space telescope's data from its first to the twelve quarter revealed three possible transit events equally spaced in time. A post-analysis in the Sixteen quarter showed that the events happened within a period of 449 days, they had a duration of 12 and half hours and a transit depth of 94 ppm.
Characteristics
KOI-4878.01 has a slightly larger radius than Earth: 1.02 Earth radii.{{Cite journal |last1=Berger |first1=Travis A. |last2=Huber |first2=Daniel |last3=Gaidos |first3=Eric |last4=van Saders |first4=Jennifer L. |last5=Weiss |first5=Lauren M. |date=September 2020 |title=The Gaia-Kepler Stellar Properties Catalog. II. Planet Radius Demographics as a Function of Stellar Mass and Age |journal=The Astronomical Journal |language=en |volume=160 |issue=3 |pages=108 |doi=10.3847/1538-3881/aba18a |doi-access=free |arxiv=2005.14671 |bibcode=2020AJ....160..108B |issn=0004-6256}} Its mass has not been measured, and is estimated to be somewhere between 0.4 - 3.0 Earth masses; likely about 0.99 Earth masses.{{Cite book|url=https://books.google.com/books?id=UNA1DwAAQBAJ&q=KOI4878&pg=PT76|title=How the Universe Works: An Illustrated Guide to the Cosmos|year=2017|publisher=Book Sales |isbn=9780785835417}}{{Cite web|last=Institute|first=CSIC|title=Exoplanets in the Milky Way|url=http://digital.csic.es/bitstream/10261/125578/55/16-Exoplanetas.pdf}} The planet has an equilibrium temperature of {{convert|257|K|C F}}, compared to the {{convert|255|K|C F}} of Earth.{{Cite journal |last1=Chawda |first1=Aryan |last2=Guinan |first2=Edward |last3=Engle |first3=Scott |date=February 2024 |title=A Better Earth? The Age and X-UV Irradiance of the Superhabitable Earth-Like Exoplanet, KOI-4878.01 |bibcode=2024AAS...24317803C |journal=American Astronomical Society Meeting Abstracts |language=en |volume=243 |pages=178.03}}
The host star's age of {{val|6.1|2.5}} billion years suggest the planet had more time for life to evolve than Earth did. As of such, some astronomers speculate that it may be more suitable for intelligent life than Earth.
| class="wikitable" style="margin-left: auto; margin-right: auto; border: none;"
!Property !Based on KIC data !Based on new data |
| Period (days)
|449.015±0.021 |449.015±0.021 |
|---|
| Semimajor Axis (AU)
|1.137 +0.053/-0.040 |1.125 |
| Planet Radius (Earth=1)
|1.04 +0.38/-0.14 |1.05 |
| Seff (Earth=1)
|1.05 |0.92 |
Habitability
The estimated features of the planet are similar to an Earth analog.{{Cite web|last=Atargatis|date=2020-11-10|title=Found more than 20 exoplanets that could host life|url=https://atargatis.news/science/found-more-than-20-exoplanets-that-could-host-life/|access-date=2020-11-12|website=Atargatis.news|language=it-IT}} It completes an orbit around its host star every 449 Earth days. Based on this, KOI-4878.01 should be in the habitable zone of the star.{{Cite book|last=Mendez|first=Abel|title=Potentially habitable worlds|url=https://iopscience.iop.org/book/978-1-6817-4401-8/chapter/bk978-1-6817-4401-8ch5}}{{Cite web|date=2016-10-07|title=Planetas habitables en los que nunca habitaremos|url=https://www.elindependiente.com/futuro/2016/10/07/planetas-habitables-habitaremos/|access-date=2020-10-04|website=El Independiente|language=es}}
See also
References
{{Reflist}}
{{2015 in space}}
{{Authority control}}{{Draco (constellation)}}{{DEFAULTSORT:KOI-4878.01}}