Kepler-37

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Kepler-37
A Moon-size Line Up.jpg
Line up comparing the planets in the Kepler-37 system to the Moon and planets in the Solar System.
Observation data
Epoch J2000       Equinox J2000
Constellation Lyra
Right ascension 18h 56m 14.30760s [1]
Declination +44° 31′ 05.3896″ [1]
Apparent magnitude  (V)9.710 [2]
Characteristics
Spectral type G8V
Astrometry
Radial velocity (Rv)−30.92±0.20 [1]  km/s
Proper motion (μ)RA: −60.396  mas/yr [1]
Dec.: 48.657  mas/yr [1]
Parallax (π)15.6253 ± 0.0105  mas [1]
Distance 208.7 ± 0.1  ly
(64.00 ± 0.04  pc)
Details
Mass 0.79+0.033
−0.03 [3]   M☉
Radius 0.789+0.0064
−0.0056 [3]   R☉
Temperature 5357±68 [3]   K
Metallicity [Fe/H]−0.36±0.05 [3]   dex
Rotational velocity (v sin i)1.1 (± 1.1) [4]  km/s
Age 7.6+3.4
−3.1 [3]   Gyr
Other designations
KOI-245, KIC 8478994, [2] TYC  3131-1199-1, BD+44 3020, 2MASS J18561431+4431052, GSC 03131-01199, Gaia DR2 2106674071344722688 [5]
Database references
SIMBAD data
KIC data

Kepler-37, also known as UGA-1785, [6] [7] [8] is a G-type main-sequence star located in the constellation Lyra 209 light-years (64 parsecs ) from Earth. It is host to exoplanets Kepler-37b, Kepler-37c, Kepler-37d and possibly Kepler-37e, all of which orbit very close to it. Kepler-37 has a mass about 80.3 percent of the Sun's and a radius about 77 percent as large. [4] It has a temperature similar to that of the Sun, but a bit cooler at 5,357 K. It has about half the metallicity of the Sun. With an age of roughly 6 billion years, [9] it is slightly older than the Sun, but is still a main-sequence star. Until January 2015, Kepler-37 was the smallest star to be measured via asteroseismology. [10]

Contents

Planetary system

The Kepler-37 planetary system [3]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b <0.79 [lower-alpha 1]   M🜨 0.1019±0.001413.367020(60)<0.09888.63+0.30
−0.53 ° 		0.3098+0.0059
−0.0076  R🜨
c <1.3  M🜨 0.1390±0.002021.301848(18)<0.09989.07+0.19
−0.33 ° 		0.755+0.033
−0.055  R🜨
d <2.0  M🜨 0.2109±0.003039.7922622(65)<0.1089.335+0.043
−0.047 ° 		2.030+0.030
−0.039  R🜨
e [11] (disputed)≥8.1±1.7 M🜨 0.2550.25±0.15———

Kepler-37b is the closest planet to Kepler-37. At the time of its discovery in February 2013, it was the smallest known exoplanet. [12] At 3,865 kilometres (2,402 mi) in diameter, it is slightly larger than the Moon. [12] It orbits Kepler-37 once every 13 days at a distance of about 0.1 astronomical units (AU). [4] Kepler-37b has a rocky surface and is believed to be too small and too close to its star to support water or maintain an atmosphere. [12] Surface temperature is estimated at 700 K (427 °C; 800 °F). [10]

Kepler-37c is around three-quarters of the diameter of Earth and orbits approximately every 21 days at a distance of just under 0.14 AU. Kepler-37d is about twice the diameter of Earth. It orbits in around 40 days at a distance of nearly 0.21 AU. [4] Neither are able to support liquid water due to their proximity to Kepler-37. [12]

A 2021 study detected Kepler-37d via radial velocity, finding a mass of about 5.4  ME, [13] but a 2023 study instead found an upper limit on its mass of only 2 ME. [3] In either case, it is not a rocky planet, but a low-density planet rich in volatiles. The periods of the three inner planets are close (within one per cent) to a 5:8:15 mean-motion resonance relationship.

In 2015, a grant was approved to further expand the Sagan Planet Walk by installing a Kepler-37d station on the Moon 384,500 kilometers (238,900 mi) away. [14]

Discovery

The Kepler-37 planets were discovered in September 2012 with the aid of transit events detected by the Kepler space telescope, and announced to the public in February 2013. [4] Computer simulation was used to rule out other astronomical phenomena mimicking planetary transits with probabilities of error <0.05% (3σ) for each potential planet. Additionally, simulation demonstrated that the proposed planetary configuration was stable. [4] The exoplanets were considerably smaller than any previously detected, leading Science World Reports to state that "a major technological improvement for the telescope" had been achieved. [12]

Thomas Barclay, an astrophysicist on the Kepler space telescope team, said the discovery was "really good news" in the search for hospitable planets, a prime objective of the project, because it demonstrated the telescope was capable of detecting Earth-sized planets. [15] However, he does not anticipate finding many planets as small as Kepler-37b due to the very small amount of light such planets obscure. [15] According to NASA scientist Jack Lissauer, the discovery of Kepler-37b "suggests such little planets are common, and more planetary wonders await as we continue to gather and analyze additional data." [10] Astronomer John Johnson of Caltech university said the discovery would have been "unimaginable" a few years ago and that the telescope had revolutionized astronomers' picture of the universe. [15]

The asteroseismology work was, in part, paid for by the Nonprofit Adopt a Star program operated by White Dwarf Research Corporation, a crowd funded non-profit organization. [16]

In 2014, a fourth planet with an orbital period of 51 days (Kepler-37e) was reported based on transit-timing variations. [17] Previously this signal was thought to be a false positive due to its low signal-to-noise ratio, and indeed later studies failed to detect either the transit or TTV signal. A study in 2021 again found that the TTV data disfavors the presence of planet e, and argued that it should be stripped of its "confirmed planet" status. [13] : 3–4, 18–19 

A 2023 study modeled the system both with and without a planet candidate at 51 days. Based on the assumption that a planet with a circular orbit of about 51 days is present, marginal radial velocity evidence was found for a sub-Neptune mass planet. Evidence of a longer-period planet candidate was also found. No additional planet has been confirmed, and the system remains with three confirmed planets. [11] : 37–38 

Notes

  1. ↑ Masses more than a few times that of the Moon result in unphysically high densities.

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<span class="mw-page-title-main">TrES-2b</span> Exoplanet in the constellation Draco, known for Darkest Exoplanet

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<span class="mw-page-title-main">Kepler-7b</span> Hot Jupiter orbiting Kepler-7

Kepler-7b is one of the first five exoplanets to be confirmed by NASA's Kepler spacecraft, and was confirmed in the first 33.5 days of Kepler's science operations. It orbits a star slightly hotter and significantly larger than the Sun that is expected to soon reach the end of the main sequence. Kepler-7b is a hot Jupiter that is about half the mass of Jupiter, but is nearly 1.5 times its size; at the time of its discovery, Kepler-7b was the second most diffuse planet known, surpassed only by WASP-17b. It orbits its host star every five days at a distance of approximately 0,06 AU. Kepler-7b was announced at a meeting of the American Astronomical Society on January 4, 2010. It is the first extrasolar planet to have a crude map of cloud coverage.

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<span class="mw-page-title-main">Kepler-10</span> Sunlike star in the constellation Draco

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<span class="mw-page-title-main">Kepler-22b</span> Super-Earth exoplanet orbiting Kepler-22

Kepler-22b is an exoplanet orbiting within the habitable zone of the Sun-like star Kepler-22. It is located about 640 light-years from Earth in the constellation of Cygnus. It was discovered by NASA's Kepler Space Telescope in December 2011 and was the first known transiting planet to orbit within the habitable zone of a Sun-like star, where liquid water could exist on the planet's surface. Kepler-22 is too dim to be seen with the naked eye.

Kepler-20 is a star about 934 light-years from Earth in the constellation Lyra with a system of at least five, and possibly six, known planets. The apparent magnitude of this star is 12.51, so it cannot be seen with the unaided eye. Viewing it requires a telescope with an aperture of 15 cm (6 in) or more. It is slightly smaller than the Sun, with 94% of the Sun's radius and about 91% of the Sun's mass. The effective temperature of the photosphere is slightly cooler than that of the Sun at 5466 K, giving it the characteristic yellow hue of a stellar class G8 star. The abundance of elements other than hydrogen or helium, what astronomers term the metallicity, is approximately the same as in the Sun. It may be older than the Sun, although the margin of error here is relatively large.

<span class="mw-page-title-main">Kepler-37b</span> Sub-Earth orbiting Kepler-37, currently the smallest known exoplanet

Kepler-37b is an exoplanet orbiting the star Kepler-37 in the constellation Lyra. As of February 2013, it is the smallest planet discovered around a main-sequence star, with a radius slightly greater than that of the Moon and slightly smaller than that of Mercury. The measurements do not constrain its mass, but masses above a few times that of the Moon give unphysically high densities.

Kepler-37c is an exoplanet discovered by the Kepler space telescope in February 2013. With an orbital period of 21 days, it is located 209 light-years away, in the constellation Lyra.

Kepler-37d is an exoplanet discovered by the Kepler space telescope in February 2013. It is located 209 light years away, in the constellation Lyra. With an orbital period of 39.8 days, it is the largest of the three known planets orbiting its parent star Kepler-37.

<span class="mw-page-title-main">Kepler-62</span> K-type star in the constellation Lyra

Kepler-62 is a K-type main sequence star cooler and smaller than the Sun, located roughly 980 light-years from Earth in the constellation Lyra. It resides within the field of vision of the Kepler spacecraft, the satellite that NASA's Kepler Mission used to detect planets that may be transiting their stars. On April 18, 2013, it was announced that the star has five planets, two of which, Kepler-62e and Kepler-62f are within the star's habitable zone. The outermost, Kepler-62f, is likely a rocky planet.

Kepler-62c is an approximately Mars-sized exoplanet discovered in orbit around the star Kepler-62, the second innermost of five discovered by NASA's Kepler spacecraft around Kepler-62. At the time of discovery it was the second-smallest exoplanet discovered and confirmed by the Kepler spacecraft, after Kepler-37b. It was found using the transit method, in which the dimming that a planet causes as it crosses in front of its star is measured. Its stellar flux is 25 ± 3 times Earth's. It is similar to Mercury.

Kepler-102 is a star 353 light-years away in the constellation of Lyra. Kepler-102 is less luminous than the Sun. The star system does not contain any observable amount of dust. Kepler-102 is suspected to be orbited by a binary consisting of two red dwarf stars, at projected separations of 591 and 627 AU.

<span class="mw-page-title-main">Kepler-452b</span> Super-Earth exoplanet orbiting Kepler452

Kepler-452b is a super-Earth exoplanet orbiting within the inner edge of the habitable zone of the sun-like star Kepler-452 and is the only planet in the system discovered by the Kepler space telescope. It is located about 1,400 light-years (430 pc) from Earth in the constellation of Cygnus.

References

  1. 1 2 3 4 5 6 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv: 2208.00211 . Bibcode:2023A&A...674A...1G. doi: 10.1051/0004-6361/202243940 . S2CID   244398875. Gaia DR3 record for this source at VizieR.
  2. 1 2 "Kepler Host Star Characteristics". Archive for Space Telescopes. STSI. 2012-02-24. Retrieved 2013-02-21.
  3. 1 2 3 4 5 6 7 Bonomo, A. S.; Dumusque, X.; et al. (September 2023). "Cold Jupiters and improved masses in 38 Kepler and K2 small planet systems from 3661 HARPS-N radial velocities. No excess of cold Jupiters in small planet systems". Astronomy & Astrophysics . 677: A33. arXiv: 2304.05773 . Bibcode:2023A&A...677A..33B. doi:10.1051/0004-6361/202346211. S2CID   258078829.
  4. 1 2 3 4 5 6 Barclay, T.; Rowe, J. F.; Lissauer, J. J.; Huber, D.; Fressin, F.; Howell, S. B.; Bryson, S. T.; Chaplin, W. J.; Désert, J.-M.; Lopez, Eric D.; Marcy, Geoffrey W.; Mullally, Fergal; Ragozzine, Darin; Torres, Guillermo; Adams, Elisabeth R.; Agol, Eric; Barrado, David; Basu, Sarbani; Bedding, Timothy R.; Buchhave, Lars A.; Charbonneau, David; Christiansen, Jessie L.; Christensen-Dalsgaard, Jørgen; Ciardi, David; Cochran, William D.; Dupree, Andrea K.; Elsworth, Yvonne; Everett, Mark; Fischer, Debra A.; et al. (2013-02-20). "A sub-Mercury-sized exoplanet". Nature. 494 (7438): 452–4. arXiv: 1305.5587 . Bibcode:2013Natur.494..452B. doi:10.1038/nature11914. ISSN   0028-0836. PMID   23426260. S2CID   205232792.
  5. ↑ "TYC 3131-1199-1". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2013-02-22.
  6. ↑ Planets in Kepler-37 star system designated ‘UGA-1785’ by NASA
  7. ↑ 211 light years away, star system named for UGA
  8. ↑ Kepler-37, Open Exoplanet catalogue
  9. ↑ Smallest Alien Planet Kepler-37b Explained (Infographic)
  10. 1 2 3 "NASA's Kepler Mission Discovers Tiny Planet System" (Press release). NASA. February 20, 2012. Retrieved February 21, 2012.
  11. 1 2 Weiss, Lauren M.; et al. (2024-01-01). "The Kepler Giant Planet Search. I. A Decade of Kepler Planet-host Radial Velocities from W. M. Keck Observatory". The Astrophysical Journal Supplement Series. 270 (1) 8. arXiv: 2304.00071 . Bibcode: 2024ApJS..270....8W . doi: 10.3847/1538-4365/ad0cab .
  12. 1 2 3 4 5 Catherine Griffin (February 21, 2013). "Tiniest Planet Yet Discovered by NASA Outside our Solar System". Science World Report. Retrieved February 21, 2013.
  13. 1 2 Rajpaul, V. M.; Buchhave, L. A.; Lacedelli, G.; Rice, K.; Mortier, A.; Malavolta, L.; Aigrain, S.; Borsato, L.; Mayo, A. W.; Charbonneau, D.; Damasso, M.; Dumusque, X.; Ghedina, A.; Latham, D. W.; López-Morales, M.; Magazzù, A.; Micela, G.; Molinari, E.; Pepe, F.; Piotto, G.; Poretti, E.; Rowther, S.; Sozzetti, A.; Udry, S.; Watson, C. A. (2021), "A HARPS-N mass for the elusive Kepler-37d: A case study in disentangling stellar activity and planetary signals", Monthly Notices of the Royal Astronomical Society, 507 (2): 1847–1868, arXiv: 2107.13900 , Bibcode:2021MNRAS.507.1847R, doi:10.1093/mnras/stab2192
  14. ↑ "Tompkins County Strategic Tourism Planning Board" (PDF). Tompkins County NY. April 15, 2015. Archived from the original (PDF) on December 27, 2016. Retrieved March 5, 2016.
  15. 1 2 3 Eryn Brown (February 21, 2013). "NASA, using Kepler space telescope, finds smallest planet yet". LA Times. Retrieved February 21, 2013.
  16. ↑ Phil Plait (February 20, 2013). "Astronomers Find the Tiniest Exoplanet Yet". Bad Astronomy blog. Slate. Retrieved February 21, 2013.
  17. ↑ Hadden, Sam; Lithwick, Yoram (2014). "Densities and Eccentricities of 139 Kepler Planets from Transit Time Variations". The Astrophysical Journal. 787 (1): 80. arXiv: 1310.7942 . Bibcode:2014ApJ...787...80H. doi:10.1088/0004-637X/787/1/80. S2CID   119097836.

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