K2-32

Last updated
K2-32
Observation data
Epoch J2000       Equinox J2000
Constellation Ophiuchus [1]
Right ascension 16h 49m 42.2602s [2]
Declination −19° 32′ 34.151″ [2]
Apparent magnitude  (V)12.31±0.02 [3]
Characteristics
Spectral type G9V [4]
Apparent magnitude  (J)10.404±0.024 [5]
Apparent magnitude  (H)9.993±0.025 [5]
Apparent magnitude  (K)9.821±0.019 [5]
Variable type Planetary transit variable [6]
Astrometry
Radial velocity (Rv)−1.82±0.14 [7]  km/s
Proper motion (μ)RA: −16.662(18) [2]   mas/yr
Dec.: −53.564(13) [2]   mas/yr
Parallax (π)6.3939 ± 0.0153  mas [2]
Distance 510 ± 1  ly
(156.4 ± 0.4  pc)
Details [3]
Mass 0.856±0.028  M☉
Radius 0.845+0.044
−0.035  R☉
Surface gravity (log g)4.49±0.05  cgs
Temperature 5275±60  K
Metallicity [Fe/H]−0.02±0.04  dex
Rotational velocity (v sin i)0.7 km/s
Age 7.9±4.5  Gyr
Other designations
Gaia DR2  4130539180358512768, EPIC  205071984, 2MASS J16494226-1932340 [8]
Database references
SIMBAD data

K2-32 is a G9-type main sequence star slightly smaller and less massive than the sun. [4] Four confirmed transiting exoplanets are known to orbit this star. [9] 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. [10]

Contents

Planetary system

Discovery

The star K2-32 was initially found to have three transiting planet candidates by Andrew Vanderburg and collaborators in 2016. [7] The innermost planet candidate, at that time, K2-32b was confirmed using radial velocity measurements made with the Keck telescope. [4] Confirmation of planets c and d was made by Sinukoff et al. using adaptive optics imaging and computer analysis to eliminate possible false positives. [6]

The Earth-sized planet K2-32e was discovered and validated by René Heller and team in 2019. [9] [11]

Transit light curves of all four planets orbiting the star K2-32. K2-32 transit light curves.png
Transit light curves of all four planets orbiting the star K2-32.

Characteristics

With periods of 4.34, 8.99, 20.66 and 31.71 days the four planets orbits are very close to a 1:2:5:7 orbital resonance chain. The densities of planets b, c, and d are between those of Saturn and Neptune, which suggests large and massive atmospheres. The planet K2-32e with a radius almost identical to that of the Earth is almost certainly a terrestrial planet. [9] All four planets are well inside even the optimistic inner boundary of the habitable zone located at 0.58 astronomical units. [12]

Planetary system of the star K2-32 showing planetary radii and orbital resonances. K2-32 planetary system.png
Planetary system of the star K2-32 showing planetary radii and orbital resonances.
The K2-32 planetary system [9] [3] [13]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
K2-32e2.1+1.3
−1.1  M🜨 		0.04899+0.00041
−0.00038		4.34934±0.000390.043+0.048
−0.030		89.0±0.7° 1.212+0.052
−0.046  R🜨
K2-32b15.0+1.8
−1.7  M🜨 		0.07950+0.00066
−0.00062		8.992±0.000080.03+0.032
−0.02		89.0+0.5
−0.3 ° 		5.299±0.191  R🜨
K2-32c8.1±2.4  M🜨 0.13843+0.00115
−0.00108		20.66093+0.00080
−0.00079		0.049+0.046
−0.035		89.4+0.3
−0.2 ° 		2.134+0.123
−0.102  R🜨
K2-32d6.7±2.5  M🜨 0.18422+0.00152
−0.00144		31.71701+0.00101
−0.00096		0.05+0.053
−0.035		89.4±0.1° 3.484+0.112
−0.129  R🜨

Related Research Articles

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<span class="mw-page-title-main">K2-25</span>

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.

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 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. 1 2 3 Petigura, Erik A.; et al. (2017). "Four Sub-Saturns with Dissimilar Densities: Windows into Planetary Cores and Envelopes". The Astronomical Journal. 153 (4) 142. arXiv: 1702.00013 . Bibcode: 2017AJ....153..142P . doi: 10.3847/1538-3881/aa5ea5 .
  4. 1 2 3 Dai, Fei; et al. (2016). "Doppler Monitoring of Five K2 Transiting Planetary Systems". The Astrophysical Journal. 823 (2) 115. arXiv: 1604.01413 . Bibcode: 2016ApJ...823..115D . doi: 10.3847/0004-637X/823/2/115 .
  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 Sinukoff, Evan; et al. (2016). "Eleven Multiplanet Systems From K2 Campaigns 1 and 2 and the Masses of Two Hot Super-Earths". The Astrophysical Journal. 827 (1) 78. arXiv: 1511.09213 . Bibcode: 2016ApJ...827...78S . doi: 10.3847/0004-637X/827/1/78 .
  7. 1 2 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 .
  8. ↑ "K2-32". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2019-09-01.
  9. 1 2 3 4 5 6 Heller, René; Rodenbeck, Kai; Hippke, Michael (2019). "Transit least-squares survey. I. Discovery and validation of an Earth-sized planet in the four-planet system K2-32 near the 1:2:5:7 resonance". Astronomy and Astrophysics. 625 A31. arXiv: 1904.00651 . Bibcode: 2019A&A...625A..31H . doi: 10.1051/0004-6361/201935276 .
  10. ↑ Kubyshkina, D.; et al. (2019). "Close-in Sub-Neptunes Reveal the Past Rotation History of Their Host Stars: Atmospheric Evolution of Planets in the HD 3167 and K2-32 Planetary Systems". The Astrophysical Journal. 879 (1) 26. arXiv: 1906.12153 . Bibcode: 2019ApJ...879...26K . doi: 10.3847/1538-4357/ab1e42 .
  11. ↑ "Astronomers Discover 18 New Small Exoplanets in Kepler Data" (Press release). Sci-News.com. 2019-05-28. Retrieved 2019-09-27.
  12. ↑ Wittenmyer, Robert A.; et al. (2018). "The K2-HERMES Survey. I. Planet-candidate Properties from K2 Campaigns 1–3". The Astronomical Journal. 155 (2) 84. arXiv: 1712.06774 . Bibcode: 2018AJ....155...84W . doi: 10.3847/1538-3881/aaa3e4 .
  13. ↑ Lillo-Box, J.; et al. (2020). "Masses for the seven planets in K2-32 and K2-233". Astronomy & Astrophysics. 640 A48. arXiv: 2006.01102 . Bibcode: 2020A&A...640A..48L . doi: 10.1051/0004-6361/202037896 .
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