K2-24

Last updated
K2-24
Observation data
Epoch J2000       Equinox J2000
Constellation Scorpius [1]
Right ascension 16h 10m 17.6977s [2]
Declination −24° 59′ 25.261″ [2]
Apparent magnitude  (V)11.068±0.110 [3]
Characteristics
Spectral type G3V [4]
Apparent magnitude  (J)9.635±0.024 [5]
Apparent magnitude  (H)9.294±0.022 [5]
Apparent magnitude  (K)9.180±0.021 [5]
Variable type Planetary transit [4]
Astrometry
Radial velocity (Rv)1.18(32) [2]  km/s
Proper motion (μ)RA: −59.891(21) [2]   mas/yr
Dec.: −58.702(14) [2]   mas/yr
Parallax (π)5.8273 ± 0.0169  mas [2]
Distance 560 ± 2  ly
(171.6 ± 0.5  pc)
Details [6]
Mass 1.041+0.017
−0.016  M☉
Radius 1.185±0.011  R☉
Surface gravity (log g)4.48±0.03  cgs
Temperature 5726±65  K
Metallicity [Fe/H]0.41±0.05  dex
Age 4.9±1.7  Gyr
Other designations
Gaia DR2  6049750234317822208, EPIC  203771098, TYC  6784-837-1, 2MASS J16101770-2459251 [7]
Database references
SIMBAD data
Exoplanet Archive data

K2-24 (also known as EPIC 203771098) is a metal-rich G3-type main sequence star larger and more massive than the Sun, located 560 light-years (172 parsecs ) away in the constellation Scorpius. Two confirmed transiting exoplanets are known to orbit this star. [4] An attempt to detect stellar companions using adaptive optics imaging at the Keck telescope was negative [4] however later observations using lucky imaging at the Danish 1.54 m telescope at La Silla Observatory detected a possible companion at 3.8 arcseconds distance from K2-24. This candidate companion being over 8 magnitudes fainter than K2-24 and with a color temperature of 5400  Kelvin , is inconsistent with a bound main sequence companion. [8]

Contents

Planetary system

Discovery

Erik A. Petigura and team analyzed data obtained from the Kepler space telescope during its observation of the K2 Campaign 2 field. They reported the discovery and confirmation of both planets b and c. [4] The Planetary signals were independently detected by Andrew Vanderburg and collaborators. [9]

Characteristics

The two known planets in this system have radii equal to 5.4 and 7.5 times that of the Earth. This places both planets radii between that of Uranus and Saturn, a range not present within the Solar System. With orbital periods of 20.9 days and 42.4 days, the planets are within 1% of the 2:1 mean-motion resonance. The low observed eccentricities and near orbital resonance provide evidence regarding the formation and evolution of the system, suggesting that they could possibly have resulted from gravitational interactions with a protoplanetary disk. K2-24c at 15.4 earth masses is significantly lighter than K2-24b's 19 Earth masses despite being a larger planet. It is estimated that K2-24b's atmosphere makes up 26% of its mass while K2-24c's atmosphere makes up 52%. The current model of core-nucleated accretion predicts that runaway accretion should occur when a planet reaches approximately 50% atmosphere by mass, this makes K2-24c a potential challenge to the model. [10]

There is also a candidate planet, K2-24d, with a mass of 53 ME and an orbital period of 470 days. While the radial velocity signal of planet was confirmed, no validation tests were run to confirm its existence, rendering it as unconfirmed. [6]

A transit observation of K2-24b with the Hubble Space Telescope's Wide Field Camera 3 suggested the presence of ammonia, in a high abundance, but did not find evidence for water. [11]

The K2-24 planetary system [6]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b 19.0+2.2
−2.1  M🜨 		0.1673+0.0034
−0.0056		20.88977+0.00034
−0.00035 [10] 		0.06±0.01 [10] 89.63±0.25 ° 5.638+0.065
−0.061  R🜨
c 16.4+1.3
−0.2  M🜨 		0.262+0.014
−0.011		42.3391±0.0012 [10] <0.05 [12] 89.44+0.15
−0.11 ° 		7.93+0.12
−0.13  R🜨
d(unconfirmed)54+9
−4 M🜨 		—469+10
−15		0.00——
The possible make up of K2-24 b and c, Consisting of a Hydrogen/Helium Atmosphere (Purple) and a rocky core (Brown). Planete geante a noyau massif.png
The possible make up of K2-24 b and c, Consisting of a Hydrogen/Helium Atmosphere (Purple) and a rocky core (Brown).

Related Research Articles

HD 114386 is a star with a pair of orbiting exoplanets in the southern constellation of Centaurus. It has an apparent visual magnitude of 8.73, which means it cannot be viewed with the naked eye but can be seen with a telescope or good binoculars. Based on parallax measurements, the system is located at a distance of 91 light years from the Sun. It is receding with a radial velocity of 33.4 km/s. The star shows a high proper motion, traversing the celestial sphere at an angular rate of 0.318 arcsec yr−1.

<span class="mw-page-title-main">WASP-1</span> Star in the constellation Andromeda

WASP-1 is a metal-rich magnitude 12 star located about 1,250 light-years away in the Andromeda constellation.

HAT-P-4 is a wide binary star consisting of a pair of G-type main-sequence stars in the constellation of Boötes. It is also designated BD+36°2593.

HAT-P-11, also designated GSC 03561-02092 and Kepler-3, is a metal-rich orange dwarf star with a planetary system, 123 light-years away in the constellation Cygnus. This star is notable for its relatively large rate of proper motion. The apparent magnitude of this star is about 9.6, which means it is not visible to the naked eye but can be seen with a medium-sized amateur telescope on a clear dark night. The age of this star is about 6.5 billion years.

<span class="mw-page-title-main">Kepler-4b</span> Extrasolar planet in the constellation Draco

Kepler-4b, initially known as KOI 7.01, is an extrasolar planet first detected as a transit by the Kepler spacecraft. Its radius and mass are similar to that of Neptune; however, due to its proximity to its host star, it is substantially hotter than any planet in the Solar System. The planet's discovery was announced on January 4, 2010, in Washington, D.C., along with four other planets that were initially detected by the Kepler spacecraft and subsequently confirmed by telescopes at the W.M. Keck Observatory.

<span class="mw-page-title-main">Kepler-25</span> Yellow-white hued star in the constellation Lyra

Kepler-25 is a star in the northern constellation of Lyra. It is slightly larger and more massive than the Sun, with a luminosity 21⁄2 times that of the Sun. With an apparent visual magnitude of 10.6, this star is too faint to be seen with the naked eye.

Kepler-29 is a Sun-like star in the northern constellation of Cygnus. It is located at the celestial coordinates: Right Ascension 19h 53m 23.6018s, Declination +47° 29′ 28.437″. With an apparent visual magnitude of 15.456, this star is too faint to be seen with the naked eye. It is a solar analog, having a close mass, radius, and temperature as the Sun. Currently the age of the star has not been determined due to its 2780 light-year distance. As of 2016 no Jovian exoplanets of 0.9–1.4 MJ have been found at a distance of 5 AU.

K2-3, also known as EPIC 201367065, is a red dwarf star with three known planets. It is on the borderline of being a late orange dwarf/K-type star, but because of its temperature, it is classified as a red dwarf.

K2-24c also known as EPIC 203771098 c is an exoplanet orbiting the Sun-like star K2-24 every 42 days. It has a density far lower than that of Saturn, which indicates that the planet is clearly a gas giant.

<span class="mw-page-title-main">K2-138</span> Star in the constellation Aquarius

K2-138, also designated EPIC 245950175 or EE-1, is a large early K-type main sequence star with a system of at least 6 planets discovered by citizen scientists. Four were found in the first two days of the Exoplanet Explorers project on Zooniverse in early April 2017, while two more were revealed in further analysis. The system is about 660 light-years away in the constellation Aquarius, within K2 Campaign 12.

K2-19 is an early K-type or late G-type main sequence star that is magnetically active, and has a light curve that exhibits variations in brightness of ~1%. It is located approximately 976 light-years away in the constellation Virgo. Three confirmed transiting exoplanets are known to orbit this star.

K2-58 is a G-type main-sequence star in the constellation of Aquarius, approximately 596 light-years from the Solar System. The star is metal-rich, having 155% of the Solar abundance of elements heavier than helium. The star is located in a region where a hypothetical observer in the K2-58 system can see Venus transiting the sun.

K2-28 is a metal rich M4-type main sequence star. One confirmed transiting exoplanet is known to orbit this star. There is another star 5.2 arcseconds to the north–east of K2-28. However, this star has a different proper motion, and is therefore physically unrelated and probably a background star.

<span class="mw-page-title-main">K2-18</span> Red dwarf star in the constellation Leo

K2-18, also known as EPIC 201912552, is a red dwarf star with two planetary companions located 124 light-years from Earth, in the constellation of Leo.

K2-32 is a G9-type main sequence star slightly smaller and less massive than the sun. Four confirmed transiting exoplanets are known to orbit this star. A study of atmospheric escape from the planet K2-32b caused by high-energy stellar irradiation indicates that the star has always been a very slow rotator.

WASP-55 is a G-type main-sequence star about 980 light-years away. The star is much younger than the Sun at approximately 1.1+0.8
−0.6 billion years. WASP-55 is similar to the Sun in concentration of heavy elements.

<span class="mw-page-title-main">K2-296b</span> Exoplanet

K2-296b is a potentially habitable planet discovered by Heller et al. in 2019, orbiting the M-dwarf star EPIC 201238110.

<span class="mw-page-title-main">K2-25</span> Red dwarf star located in the Hyades cluster

K2-25 is a young red dwarf star located in the Hyades cluster. There is a single known Neptune-sized planet in a 3.5 day orbit.

HAT-P-67 is a binary star system, made up of a F-type subgiant and a red dwarf star, which is located about 1,200 light-years away in the constellation Hercules. There is a hot Saturn planet orbiting the primary star, which is named HAT-P-67b.

References

  1. ↑ Roman, Nancy G. (1987). "Identification of a Constellation From a Position". Publications of the Astronomical Society of the Pacific. 99 (617): 695–699. Bibcode: 1987PASP...99..695R . doi: 10.1086/132034 . Vizier query form
  2. 1 2 3 4 5 6 Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics . 649: A1. arXiv: 2012.01533 . Bibcode:2021A&A...649A...1G. doi: 10.1051/0004-6361/202039657 . S2CID   227254300. (Erratum:  doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  3. ↑ Henden, A. A.; et al. (2016). "VizieR Online Data Catalog: AAVSO Photometric All Sky Survey (APASS) DR9 (Henden+, 2016)". VizieR On-line Data Catalog: II/336. Originally Published in: 2015AAS...22533616H. 2336. Bibcode:2016yCat.2336....0H. Vizier catalog entry
  4. 1 2 3 4 5 Petigura, Erik A.; et al. (2016). "Two Transiting Low Density Sub-Saturns from K2". The Astrophysical Journal. 818 (1) 36. arXiv: 1511.04497 . Bibcode: 2016ApJ...818...36P . doi: 10.3847/0004-637X/818/1/36 .
  5. 1 2 3 Skrutskie, Michael F.; et al. (1 February 2006). "The Two Micron All Sky Survey (2MASS)". The Astronomical Journal. 131 (2): 1163–1183. Bibcode: 2006AJ....131.1163S . doi: 10.1086/498708 . Vizier catalog entry
  6. 1 2 3 Nascimbeni, V.; Borsato, L.; Leonardi, P.; Sousa, S. G.; Wilson, T. G.; Fortier, A.; Heitzmann, A.; Mantovan, G.; Luque, R. (2024-09-16). "The K2-24 planetary system revisited by CHEOPS". arXiv: 2409.02995 .
  7. ↑ "K2-24". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2019-09-27.
  8. ↑ Evans, D. F.; et al. (2018). "High-resolution Imaging of Transiting Extrasolar Planetary systems (HITEP). II. Lucky Imaging results from 2015 and 2016". Astronomy and Astrophysics. 610 A20. arXiv: 1709.07476 . Bibcode: 2018A&A...610A..20E . doi: 10.1051/0004-6361/201731855 .
  9. ↑ Vanderburg, Andrew; et al. (2016). "Planetary Candidates from the First Year of the K2 Mission". The Astrophysical Journal Supplement Series. 222 (1) 14. arXiv: 1511.07820 . Bibcode: 2016ApJS..222...14V . doi: 10.3847/0067-0049/222/1/14 .
  10. 1 2 3 4 Petigura, Erik A.; et al. (2018). "Dynamics and Formation of the Near-resonant K2-24 System: Insights from Transit-timing Variations and Radial Velocities". The Astronomical Journal. 156 (3) 89. arXiv: 1806.08959 . Bibcode: 2018AJ....156...89P . doi: 10.3847/1538-3881/aaceac .
  11. ↑ Edwards, Billy; et al. (2023-11-01). "Exploring the Ability of Hubble Space Telescope WFC3 G141 to Uncover Trends in Populations of Exoplanet Atmospheres through a Homogeneous Transmission Survey of 70 Gaseous Planets". The Astrophysical Journal Supplement Series. 269 (1) 31. Appendix B.9. arXiv: 2211.00649 . Bibcode: 2023ApJS..269...31E . doi: 10.3847/1538-4365/ac9f1a .
  12. ↑ Antoniadou, Kyriaki I.; Libert, Anne-Sophie (23 June 2020). "Exploiting periodic orbits as dynamical clues for Kepler and K2 systems". Astronomy & Astrophysics. 640 A55. arXiv: 2006.12895 . Bibcode: 2020A&A...640A..55A . doi: 10.1051/0004-6361/202037779 . S2CID   219980541.
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