| TRAPPIST-1 | |||
|---|---|---|---|
| Star | |||
 TRAPPIST-1 in the artist's view during the transit of two of the seven famous planets | |||
| Observational data ( Age J2000.0 ) | |||
| Type of | single star | ||
| Right ascension | |||
| Declination | |||
| Distance | 39.5 ± 1.3 St. years (12.1 ± 0.4 pc ) [1] | ||
| Visible magnitude ( V ) | 18.80 [1] | ||
| Constellation | Aquarius | ||
| Astrometry | |||
| Radial velocity ( R v ) | |||
| Own movement (μ) | RA: 890 mas per year Dec: −420 mas per year | ||
| Parallax (π) | 82.6 ± 2.6 mas | ||
| Absolute magnitude (V) | |||
| Specifications | |||
| Spectral class | M8.0 ± 0.5 [1] | ||
| physical characteristics | |||
| Weight | 0.0802 ± 0.0073 [3] M ☉ | ||
| Radius | 0.121 ± 0.003 [4] R ☉ | ||
| Age | 7.6 ± 2.2 billion [4] years | ||
| Temperature | 2559 ± 50 [3] K | ||
| Luminosity | 0.000524 ± 0.000034 [3] L ☉ | ||
| Metallicity | [Fe / H] = +0.04 ± 0.08 | ||
| Rotation | 3.295 ± 0.003 days [5] | ||
| |||
| Database Information | |||
| SIMBAD | data | ||
TRAPPIST-1 (also 2MASS J23062928-0502285 or EPIC 246199087 ) [8] is a single star in the constellation Aquarius . Located at a distance of 39.5 St. years from the sun. In 2016, a planetary system consisting of three planets was discovered. On February 22, 2017, four more planets were announced, of which 3 are in the habitable zone [9] [10] [11] .
Content
Features
| Jupiter | TRAPPIST-1 |
|---|---|
It is a red dwarf of the spectral class M8 V [1] . The apparent magnitude TRAPPIST-1 m V = 18.80 m , while in red and infrared light it is much brighter: in the R filter, its brightness is 16.47 m , in J - 11.35 m , in K - 10.30 m [6] . The radius of the star is 12.1% of the radius of the Sun [4] , which is slightly larger than the radius of Jupiter [3] [12] . Moreover, its mass is equal to 0.080 ± 0.007 solar masses [3] , or ~ 84 masses of Jupiter [1] . The average density of a star, determined by planetary transits, is 49.3 + 4.1
−8.3 times the average density of the Sun [12] . The surface temperature is estimated at 2559 ± 50 K [1] . Its luminosity is approximately 1900 times less than the luminosity of the Sun [1] . Before observations by the Kepler telescope, it was believed that the rotation period is 1.40 ± 0.05 days [12] , however, new data indicate 3.295 ± 0.003 days [5] . The star’s activity turned out to be moderate, the frequency of flares with a power above 1% of the average luminosity is 30 times less than that of stars of the M6-M9 classes. Based on these, as well as a number of other data, the age of the star was re-estimated; now it is believed that it is equal to 7.6 ± 2.2 billion years [4] [7] [13] . Prior to this, it was only known that TRAPPIST-1 is older than 500 million years [3] .
A star has a rather high proper motion , moving across the celestial sphere by 1.04 arc seconds per year [6] . Its radial velocity is −56.3 ± 0.3 km / s, the star is approaching the Sun [6] .
Planet System
Discovery History
In May 2016, a group of astronomers from Belgium and the USA , led by Michael Gillon ( fr. Michaël Gillon ), announced [14] the discovery of three transit planets in the dim cold red dwarf system 2MASS J23062928-0502285 using a robotic 0.6-meter telescope TRAPPIST , located at the ESO La Silla observatory in Chile [15] . The results of the study were published in the journal Nature [12] . The planets received the designations TRAPPIST-1 b , TRAPPIST-1 c and TRAPPIST-1 d , in order of distance from the star. However, during subsequent observations it was found that the initial observation of the third planet, TRAPPIST-1 d, was erroneous - its alleged transit was in fact a coincidence of the passage of other stars of the planet at that time of the planet’s unknown planets. More detailed observations of the system made it possible to discover the real third planet along with four other Earth-like transit planets ( e , f , g and h ), the parameters of which were presented at the NASA press conference on February 22, 2017 [16] and simultaneously published in the journal Nature [3 ] . These additional observations were made using several ground-based telescopes and the Spitzer space telescope, which measured the brightness of a star for almost 20 days in September 2016. Thus, the total number of planets in the system reached seven, while the period of revolution of TRAPPIST-1h was not accurately measured by Spitzer, since the planet was observed only 1 time. But the Kepler telescope, within the framework of the K2 mission, observed changes in the brightness of TRAPPIST-1 in the twelfth region from December 15, 2015 to March 4, 2017, respectively, was able to detect more transits and determine the exact period of revolution of the seventh planet [7] [13] . A month later, on April 13, using the same data, the parameters of all the planets in the system were refined [17] .
Options
Seven open exoplanets of the TRAPPIST-1 system are close in size to the Earth [1] (their radii range from 0.71 R ⊕ for TRAPPIST-1 h to 1.13 R ⊕ for TRAPPIST-1 g), and the approximate mass was measured by timing transits. The periods of revolution around the parent star for the two inner planets, b and c, are 1.51 and 2.42 days, respectively. It was assumed that both planets are hot analogues of Venus [1] . However, after measuring the mass and density of the planets, it turned out that the second planet, TRAPPIST-1 c, can be an analogue of Venus, and the first planet, TRAPPIST-1 b, is more likely to contain a lot of water or other volatile substances in its composition [18] . The period of revolution of the third planet was not initially determined and it was assumed that it lies in the range from 4.6 to 72.8 days. But, after the publication of the results of the analysis of planetary transits (made by the Spitzer telescope), it was found that the initial identification of the third planet was erroneous. The planet TRAPPIST-1 d, discovered in the course of new observations, turns in 4.05 days and has a radius of 0.77 R ⊕ [3] [19] . In addition, based on these data, new exoplanets were discovered: TRAPPIST-1 e with an orbital period of 6.1 days and a radius of 0.92 R ⊕ ; TRAPPIST-1 f with an orbital period of 9.2 days and a radius of 1.04 R ⊕ ; TRAPPIST-1 g with an orbital period of 12.3 days and a radius of 1.13 R ⊕ ; as well as the seventh planet to be removed - TRAPPIST-1 h. Due to the fact that Spitzer was able to record only one transit of the planet, its parameters were not initially determined exactly (the orbital period was calculated by the transit time and was assumed to be approximately 20 days, and the radius was 0.75 R ⊕ ) [3] . After processing the observations of the Kepler telescope, it became known that in fact TRAPPIST-1 h turns in 18 days and has a radius of 0.7 Earth [7] . Only a month later, its more accurate parameters became known, and the data of the remaining planets of the system were significantly refined. It turned out that the masses in the previous study were overvalued. So, the density of six planets indicates the presence of a noticeable fraction of water and other volatile substances in their composition. The four extreme planets, namely e, f, g, and h, can almost entirely consist of water. Only the planet TRAPPIST-1 c has a mass larger than previously predicted, and may contain more than 50% iron in its composition [17] .
Also, based on Kepler’s data, enthusiasts from the Planet Hunters project for an amateur search for exoplanets also suggested the presence of another planet in the system, with an orbital period of 26.736 days [20] [21] . However, this discovery has not yet been confirmed in more reliable sources [13] .
The following table shows the characteristics of the planets of the system, determined with a statistical certainty of 1 σ [17] :
| Planet | Radius ( R ⊕ ) | Weight ( M ⊕ ) | Average density ( g / cm³ ) | Circulation period ( days ) | Semimajor axis ( a.u. ) | Eccentricity |
|---|---|---|---|---|---|---|
| TRAPPIST-1 b | 1,086 ± 0,035 | 0.79 ± 0.27 | 3.4 ± 1.2 | 1.5108739 ± 0.0000075 | 0.01111 | 0.019 ± 0.008 |
| TRAPPIST-1 c | 1,056 ± 0,035 | 1.63 ± 0.63 | 7.63 ± 3.04 | 2.421818 ± 0.000015 | 0.01522 | 0.014 ± 0.005 |
| TRAPPIST-1 d | 0.772 ± 0.030 | 0.33 ± 0.15 | 3.95 ± 1.86 | 4.04982 ± 0.00017 | 0,02145 | 0.003 + 0.004 −0.003 |
| TRAPPIST-1 e | 0.918 ± 0.039 | 0.24 +0.56 −0.24 | 1.71 + 4.0 −1.71 | 6.099570 ± 0.000091 | 0,02818 | 0.007 ± 0.003 |
| TRAPPIST-1 f | 1,045 ± 0,038 | 0.36 ± 0.12 | 1.74 ± 0.61 | 9.20648 ± 0.00053 | 0,0371 | 0.011 ± 0.003 |
| TRAPPIST-1 g | 1.127 ± 0.041 | 0.566 ± 0.038 | 2.18 ± 0.28 | 12.35281 ± 0.00044 | 0,0451 | 0.003 ± 0.002 |
| TRAPPIST-1 h | 0.715 ± 0.047 | 0.086 ± 0.084 | 1.27 ± 1.27 | 18.76626 ± 0.00068 | 0,0596 | 0.086 ± 0.032 |
Resonances
The orbital periods of all known planets of the system are multiples of each other and are in resonance . This is the longest resonance chain among exoplanets. It is assumed that it arose due to interactions that occur during the migration of planets from external regions to internal ones after their formation in the protoplanetary disk. If so, then the chances of finding a significant amount of water on these planets increase [7] [22] .
| TRAPPIST-1 b | TRAPPIST-1 c | TRAPPIST-1 d | TRAPPIST-1 e | TRAPPIST-1 f | TRAPPIST-1 g | TRAPPIST-1 h | |
|---|---|---|---|---|---|---|---|
| General resonance | 24/24 | 24/15 | 24/9 | 24/6 | 24/4 | 24/3 | 24/2 |
| Resonance with next the planet | 8/5 (1,603) | 5/3 (1,672) | 3/2 (1,506) | 3/2 (1,509) | 4/3 (1,342) | 3/2 (1,519) | ? |
Potential habitability
Of the seven known planets of the system today, three are in the inhabited zone of TRAPPIST-1: e, f and g. According to the measured density, planet b can either have a small core, or, more likely, contain a significant proportion of water or other volatile substances in its composition. Due to the too high surface temperature of the first two planets (+127 and +69), maintaining water in liquid form on them is extremely unlikely. Planet f has a fairly low density and can be an ocean planet [3] [18] . According to the models proposed at Cornell University , it is assumed that the habitat zone of TRAPPIST-1 can be wider if we consider volcanic hydrogen as a potential greenhouse gas that contributes to an increase in climate temperature. This means that not three, but four planets can enter the habitable zone [23] . The X-ray radiation of the TRAPPIST-1 corona is approximately equal to the X-ray radiation of Proxima Centauri , and the ultraviolet radiation ( Lyman series ) created by hydrogen atoms from the chromospheric layer of the star located under the corona in TRAPPIST-1 turned out to be 6 times less than the ultraviolet radiation of Proxima Centauri [24] . For this reason, the two planets closest to the star, TRAPPIST-1 b and TRAPPIST-1 c, could lose their atmosphere and hydrosphere in a period of 1 to 3 billion years if their initial masses are similar to terrestrial ones. However, replenishment of atmospheric hydrogen and oxygen can occur due to the photodissociation of water, if the planets contain a lot of it in their composition.
| TRAPPIST-1 b | TRAPPIST-1 c | TRAPPIST-1 d | TRAPPIST-1 e | TRAPPIST-1 f | TRAPPIST-1 g | TRAPPIST-1 h | |
|---|---|---|---|---|---|---|---|
| Insolation ( I ⊕ ) | 4.25 ± 0.33 | 2.27 ± 0.18 | 1.143 ± 0.088 | 0.662 ± 0.051 | 0.382 ± 0.030 | 0.258 ± 0.020 | 0.131 +0.081 −0.067 |
| Equilibrium temperature ( K ) | 400 | 342 | 288 | 251 | 219 | 199 | 167 |
| Equilibrium temperature ( ° C ) | +127 | +69 | +15 | −22 | −54 | −74 | −106 |
The equilibrium temperature of the planets in table [17] is given under the assumption of zero Bond albedo (that is, in the absence of scattering of incident light by the atmosphere) and in the absence of the greenhouse effect of the atmosphere. For comparison, the equilibrium temperature of the Earth in its orbit around the Sun, under the same assumptions, would be equal to 279 K , or +4 ° C , Mars - 226 K , or −47 ° C [25] .
In November 2017, it was believed that the activity of the star does not allow its planets to hold and shape the atmosphere. However, in December of the same year, in one study, it was shown that the atmosphere can be preserved even with such aggressive star activity, and for the TRAPPIST-1 system, the planets g and h can have an atmosphere. It is assumed that this issue will be resolved by direct observation by the James Webb telescope in 2019 [26] .
Gallery
Comparison of the sizes of the Sun and the star TRAPPIST-1. Since the effective temperature of a small star is much lower than the sun, it looks more red
The habitable zone of the TRAPPIST-1 system (highlighted in green), in comparison with the similar temperature zone of the solar system
Comparison of the planetary system TRAPPIST-1 with the solar system and the satellite system of Jupiter
Comparison of the sizes of the bodies of the solar system and TRAPPIST-1
Change in brightness of TRAPPIST-1 due to planetary transits for 21 days (September-October 2016)
Change in brightness during transit. The larger the planet, the deeper the trail it leaves. The farther from the star, the longer. (According to the Spitzer telescope)
View from the surface of the planet TRAPPIST-1 d in the artist's view
The artist's idea of the TRAPPIST-1 system: a view from the orbit of TRAPPIST-1d
View from the surface of the planet TRAPPIST-1 f as presented by the artist
Parameters and artistic images of TRAPPIST-1 planets in comparison with terrestrial planets
Artistic image of the structure of the planetary system
On this star map of the constellation Aquarius , the position of the star TRAPPIST-1 is marked. Despite its relative proximity to the Earth, it has too low a luminosity and a small diameter to be able to see even with a small telescope
TRAPPIST-1 position relative to galactic coordinates:
Galactic longitude 69.7127 (in the right part of the image), galactic latitude -56.6446 (in the lower part of the image), the distance is 39.5 light years (near the fourth circle)
Video
- Play media file
Video (00:44) - Imaginary journey from Earth to the TRAPPIST-1 system
- Play media file
Video (00:22) - Estimated view of TRAPPIST-1 and two planets from the vicinity of TRAPPIST-1d
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Video (01:32) - Orbits of the planets of the TRAPPIST-1 system and their transits for 22 days
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Video (01:10) - Fly around each of the planets of the TRAPPIST-1 system in the artist's view
See also
- Gj 1214
- Gj 1132
- The viability of the red dwarf system
Notes
- ↑ 1 2 3 4 5 6 7 8 9 Temperate Earth-sized planets transiting a nearby ultracool dwarf star , http://www.eso.org/public/russia/ .
- ↑ 1 2 3 4 Gaia Data Release 2 - 2018.
- ↑ 1 2 3 4 5 6 7 8 9 10 Gillon M. et al. Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1 (Eng.) // Nature. - 2017 .-- Vol. 542. - Iss. 7642 . - P. 456-460. - ISSN 0028-0836 . - DOI : 10.1038 / nature21360 . - arXiv : 1703.01424 .
- ↑ 1 2 3 4 Burgasser AJ, Mamajek EE (2017), "On the Age of the TRAPPIST-1 System", arΧiv : 1706.02018 [astro-ph]
- ↑ 1 2 Vida K., Kővári Zs., Pál A., Oláh K., Kriskovics L. Frequent Flaring in the TRAPPIST-1 System — Unsuited for Life? (Eng.) // The Astrophysical Journal. - 2017 .-- Vol. 841. - Iss. 2 . - P. 124. - ISSN 1538-4357 . - DOI : 10.3847 / 1538-4357 / aa6f05 . - arXiv : 1703.10130 .
- ↑ 1 2 3 4 2MASS J23062928-0502285 . SIMBAD Center de Données astronomiques de Strasbourg .
- ↑ 1 2 3 4 5 Luger R. et al. A seven-planet resonant chain in TRAPPIST-1 (Eng.) // Nature Astronomy. - 2017 .-- Vol. 1. - Iss. 6 . - P. 0129. - ISSN 2397-3366 . - DOI : 10.1038 / s41550-017-0129 . - arXiv : 1703.04166v2 .
Luger R. et al. (2017), "A terrestrial-sized exoplanet at the snow line of TRAPPIST-1", arΧiv : 1703.04166v1 [astro-ph.EP] - ↑ 2MASS J23062928-0502285 . simbad.u-strasbg.fr. Date of treatment May 4, 2016.
- ↑ NASA Announces a Single Star Is Home to Earthlike Planets . Time Date of treatment February 22, 2017.
- ↑ Chang, Kenneth . 7 Earth-Size Planets Identified in Orbit Around a Dwarf Star , The New York Times (February 22, 2017). Date of treatment February 22, 2017.
- ↑ Koren, Marina . Seven Earth-Like Planets Have Been Spotted Around a Nearby Star , The Atlantic . Date of treatment February 22, 2017.
- ↑ 1 2 3 4 Gillon M. et al. Temperate Earth-sized planets transiting a nearby ultracool dwarf star (Eng.) // Nature. - 2016. - Vol. 533. - Iss. 7602 . - P. 221-224. - ISSN 0028-0836 . - DOI : 10.1038 / nature17448 .
- ↑ 1 2 3 Earth-sized planet on a snow line in the TRAPPIST-1 system , Solar system - Section of the Council of the RAS for Outer Space (17-03-2017).
- ↑ Gillon, Michaël. Near a potentially ultra-cold dwarf, three potentially inhabited planets were found : This is perhaps the most promising place to search for life outside the Solar System: Scientific release eso1615ru / Michaël Gillon, Kirill Maslennikov, Julien de Wit ... [ and others. ] . - 2016 .-- May 2.
- ↑ Welcome to the TRAPPIST telescope network (inaccessible link) . Date of treatment May 3, 2016. Archived on May 5, 2016.
- ↑ Ulasovich, Christina. Found a system with seven earth-like exoplanets : [ Russian ] // N + 1: electr. ed. - 2017. - February.
- ↑ 1 2 3 4 Wang, Songhu. Updated Masses for the TRAPPIST-1 Planets: [ eng. ] / Songhu Wang, Dong-Hong Wu, Thomas Barclay ... [ et al. ] // arXiv. - 2017 .-- April. - arXiv : 1704.04290 .
- ↑ 1 2 TRAPPIST-1: seven earth-sized planets in one system , http://www.allplanets.ru/index.htm
- ↑ Planet TRAPPIST-1 d . exoplanet.eu .
- ↑ C12 K2 Finds . Talk Planet Hunters 3. - "Interestingly the planet candidate with period 26.736 does not show in the Spitzer lightcurve."
- ↑ The raw cadence data for the K2 observations of the TRAPPIST-1 system are now available . Mikulski Archive for Space Telescopes (MAST) . - "P = 26.74 days, starting at BKJD 2923.195, duration 1.5 hours, depth 0.0099 (planet Y)."
- ↑ Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1 (eng.) // arXiv. - 2017 .-- February 23.
- ↑ Makarov, Vasily TRAPPIST-1 may be suitable for life . new research . Popular Mechanics (March 1, 2017) . Date of treatment August 3, 2019.
- ↑ Bourrier, V. Reconnaissance of the TRAPPIST-1 exoplanet system in the Lyman-α line / V. Bourrier, D. Ehrenreich, PJ Wheatley ... [ et al. ] // Astronomy & Astrophysics. - 2017 .-- Vol. 599, no. March (February 23). - P. L3. - arXiv : 1702.07004 . - DOI : 10.1051 / 0004-6361 / 201630238 .
- ↑ George HA Cole, Michael M. Woolfson. Planetary Science: The Science of Planets around Stars. - 2nd Ed. - CRC Press, 2013 .-- 607 p. - P. 443 . - ISBN 978-1-4665-6316-2
- ↑ Vasily Makarov. Planets in the TRAPPIST-1 system can still have an atmosphere . Popular mechanics (January 4, 2018). Date of treatment January 4, 2018.
Links
- TRAPPIST-1 . Presenting humanity with many opportunities to study terrestrial worlds beyond our Solar system . - Site dedicated to the star system TRAPPIST-1.
- Largest batch of Earth-size, habitable zone planets . Exoplanet Exploration . NASA - The TRAPPIST-1 system on the NASA website. Date of treatment August 3, 2019.
- Keshelava, Timur Star named TRAPPIST-1 . found another analogue of the solar system . Indicator (February 22, 2017) . Date of treatment February 23, 2017.
- Shartogasheva, Anastasia NASA spoke about the new opening at the press conference, which everyone was waiting for . Popular Mechanics (February 22, 2017). Date of treatment August 3, 2019.