TRAPPIST-1 h - exoplanet of the star TRAPPIST-1 in the constellation Aquarius , having a diameter close to the diameter of the Earth . The most distant from the star of the seven planets in the system . The discovery was announced on February 22, 2017 at the press conference of NASA , where it also became known about the planets TRAPPIST-1 e , TRAPPIST-1 f and TRAPPIST-1 g [1] [2] [3] . The parameters were refined after collecting data from the Kepler telescope on March 12, 2017 [4] [5] . The discovery of other planets ( b , c and d ) was announced a year earlier, on May 2, 2016 [6] [7] [8] .
| TRAPPIST-1 h | |
|---|---|
| Exoplanet | |
 TRAPPIST-1 h in the view of the artist. | |
| Parent star | |
| Star | TRAPPIST-1 |
| Orbit elements | |
| Semi-axis ( a ) | 0.063 +0.027 −0,013 a. e. |
| Orbital period ( P ) | 18,764 +0,008 −0.009 d |
| Inclination ( i ) | 89.8 ± 0.3 ° |
| physical characteristics | |
| Mass ( m ) | 0.086 ± 0.084 M ⊕ |
| Radius ( r ) | 0.715 +0.047 −0,043 R ⊕ |
| Density ( ρ ) | 1.27 ± 1.27 g / cm 3 |
| Temperature ( T ) | −104.1 ± 4 ° C 169 ± 4 K |
| Opening Information | |
| opening date | February 22, 2017 |
| Detection method | Transit method |
| Other designations | |
| • 2MASS J23062928-0502285 h • WISE J230630.02-050234.1 h • EPIC 246199087 h | |
Content
Characteristics
TRAPPIST-1 h was discovered by the Spitzer telescope using the transit method according to observations containing only one planet transit. Therefore, it was impossible to accurately determine the orbital period, the distance to the star and the radius , and the mass and density could not be named. Then the year of the planet was estimated by the duration of transit as 20 days, the big semi-axis was 0.06 AU. and the radius is 0.75 from the earthly [9] .
| Land | TRAPPIST-1 h |
|---|---|
But within the framework of the K2 mission, the Kepler telescope monitored the transit of the entire system from December 15, 2015 to March 4, 2017. So it was able to detect more transits and determine the exact parameters of TRAPPIST-1 h. According to these data, the orbital period is 18.8 Earth days , the distance to the star is 0.06 AU. with an inclination of 89.8 ° and an eccentricity of 0.09. It has a small radius (0.715 R ), and an even smaller mass (0.086 M ). These are the lowest values in the planetary system. Based on these data, the average density is 1.27 g / cm 3 , which indicates an almost pure ice composition of the planet [10] [4] . The estimated surface temperature without taking into account the greenhouse effect of the atmosphere is estimated as −104 ° C , that is, TRAPPIST-1 h receives about the same heat as the main asteroid belt in the Solar System [5] .
Parent Star
The planet revolves around the ultracold dwarf star TRAPPIST-1 of spectral class M. The star has a mass of 0.08 M ☉ and a radius of 0.11 R ☉ . The surface temperature is 2559 ± 50 K (approximately 2290 ° C ). The star is at least 500 million years old. For comparison, the surface temperature of the Sun is 5778 K and its age is about 4.6 billion years. TRAPPIST-1 has a metallicity close to solar: [Fe / H] = 0.04 ± 0.08 (or from 91% to 132% solar metallicity), and the luminosity is only 0.052% of the solar luminosity . Because of the low luminosity, the apparent stellar magnitude of TRAPPIST-1 is 18.8 m [9] , that is, the star cannot be seen either with the naked eye or in an average amateur telescope.
Potential habitability
It is believed that in the habitable zone of TRAPPIST-1 there are three planets - e , f and g . However, according to the models proposed at Cornell University , it is possible to maintain liquid water, 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 fall into the habitat zone of TRAPPIST-1 [11] [12] .
Notes
- ↑ Gillon M. et al. Seven temperate terrestrial planets around the TRAPPIST-1 ultracool dwarf star (Eng.) // Nature. - 2017. - Vol. 542. - Iss. 7642 . - P. 456-460. - ISSN 0028-0836 . - DOI : 10.1038 / nature21360 . - arXiv : 1703.01424 .
- ↑ Found a system with seven earth-like exoplanets (rus.) // N + 1. - 2017. - 22 February.
- ↑ NASA telescope opens the largest batch of Earth-sized planets in the habitable zone around a single star. , NASA (2010-02-22).
- ↑ 1 2 A terrestrial-sized exoplanet at TRAPPIST-1 (Eng.) // arXiv: pdf document. - 2017. - 12 March.
- ↑ 1 2 Earth-sized planet on the snow line in the TRAPPIST-1 system , Solar System - Section of the RAS Council on Space (17-03-2017).
- ↑ 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 .
- ↑ Three potentially habitable worlds found around a near ultracold red dwarf (Eng.) // European Southern Observatory. - 2016. - 2 May.
- ↑ Astronomers immediately found three exoplanets in the potentially habitable zone TRAPPIST-1 (rus.) // N + 1. - 2016. - 3 May.
- ↑ 1 2 Planet TRAPPIST-1 h . The Extrasolar Planets Encyclopaedia (February 22, 2017).
- ↑ Updated Masses for the TRAPPIST-1 Planets (Eng.) // arXiv. - 2017. - April 13th.
- ↑ TRAPPIST-1 may be suitable for life: new research (rus.) , Popular Mechanics (02-03-2017).
- ↑ Planetologists have expanded the list of planets suitable for life , INFOX (28-02-2017).