Kepler-298d

{{Short description|Exoplanet in the habitable zone}}

{{Infobox planet

| name = Kepler-298d

| discoverer = Jason F. Rowe et al.{{cite journal|bibcode=2014ApJ...784...45R|doi=10.1088/0004-637X/784/1/45|arxiv=1402.6534|display-authors=1|title=Validation of Kepler's Multiple Planet Candidates. III. Light Curve Analysis and Announcement of Hundreds of New Multi-planet Systems|last1 = Rowe| first1 = Jason F.| last2 = Bryson| first2 = Stephen T.| last3 = Marcy| first3 = Geoffrey W.| last4 = Lissauer| first4 = Jack J.| last5 = Jontof-Hutter| first5 = Daniel| last6 = Fergal Mullally| last7 = Gilliland| first7 = Ronald L.| last8 = Issacson| first8 = Howard| last9 = Ford| first9 = Eric| last10 = Howell| first10 = Steve B.| last11 = Borucki| first11 = William J.| last12 = Michael Haas| last13 = Huber| first13 = Daniel| last14 = Steffen| first14 = Jason H.| last15 = Thompson| first15 = Susan E.| last16 = Quintana| first16 = Elisa| last17 = Barclay| first17 = Thomas| last18 = Martin Still| last19 = Fortney| first19 = Jonathan| last20 = T. N. Gautier| first20 = III| last21 = Hunter| first21 = Roger| last22 = Caldwell| first22 = Douglas A.| last23 = Ciardi| first23 = David R.| last24 = Edna Devore| last25 = Cochran| first25 = William| last26 = Jenkins| first26 = Jon| last27 = Agol| first27 = Eric| last28 = Carter| first28 = Joshua A.| last29 = Geary| first29 = John|journal=The Astrophysical Journal|volume=784|issue=1|id=45|pages=20|date=2014|s2cid=119118620 }}

| discovery_site = Kepler

| discovered = February 26, 2014

| discovery_method = Transit method

| apsis = astron

| period = 77.473633 d

| time_periastron = JD 2454985.64156

| star = Kepler-298

| mean_radius = 2.50 ± 0.20 {{Earth radius|link=y}}

| density = {{convert|2.8203|±|4.0164|g/cm3|lk=on|abbr=on}}

}}

Kepler-298d is an exoplanet orbiting within the habitable zone of the orange dwarf star Kepler-298, located 1545 light years (473.69 parsecs) away from Earth. It was discovered in 2014 via the transit method.{{cite encyclopedia|url=https://exoplanet.eu/catalog/kepler_298_d--1890/|encyclopedia=Extrasolar Planets Encyclopaedia|title=Planet Kepler-298 d|access-date=26 April 2018}} The planet was originally considered to be potentially habitable,{{cite journal |last1=Safonova |first1=M. |last2=Murthy |first2=J. |last3=Shchekinov |first3=Yu. A. |title=Age aspects of habitability |journal=International Journal of Astrobiology |date=27 August 2018 |volume=15 |issue=2 |page=10 |doi=10.1017/S1473550415000208 |arxiv=1404.0641 }} but further research places its atmosphere at +2.11 on the HZA scale,{{technical inline|date=January 2025}} meaning it may be an ocean planet with a thick gas atmosphere like a gas dwarf.{{Cn|date=December 2023}}