TOI-700

Last updated

TOI-700
PIA23407-TOI700-PlanetarySystem.jpg
TOI-700 planetary system as of 2020
Credit: NASA's Goddard Space Flight Center
Observation data
Epoch J2000       Equinox J2000
Constellation Dorado [1] [2]
Right ascension 06h 28m 22.97s [3]
Declination −65° 34 43.01 [3]
Apparent magnitude  (V)13.10±0.01 [4]
Characteristics
Evolutionary stage Main sequence
Spectral type M2V [4]
Astrometry
Radial velocity (Rv)-4.4±0.1 [4]  km/s
Proper motion (μ)RA: -102.750±0.051 [5]   mas/yr
Dec.: 161.805±0.060 [5]   mas/yr
Parallax (π)32.0980 ± 0.0211  mas [5]
Distance 101.61 ± 0.07  ly
(31.15 ± 0.02  pc)
Details
Mass 0.416 ± 0.010 [4]   M
Radius 0.420 ± 0.031 [4]   R
Luminosity 0.0233 ± 0.0011 [4]   L
Surface gravity (log g)4.81 ± 0.06 [4]   cgs
Temperature 3480 ± 135 [4]   K
Metallicity [Fe/H]-0.07 ± 0.11 [4]   dex
Rotation 54.0 ± 0.8 [4] d
Age >1.5 [4]   Gyr
Other designations
TIC 150428135, UCAC3 49-21611, 2MASS J06282325-6534456, WISE J062823.05-653443.7, APASS 31812705, Gaia DR2 5284517766615492736
Database references
SIMBAD data

TOI-700 is a red dwarf 101.4 light-years away from Earth [3] [5] located in the Dorado constellation that hosts TOI-700 d, the first Earth-sized exoplanet in the habitable zone discovered by the Transiting Exoplanet Survey Satellite (TESS). [1] [2] [6]

Contents

Nomenclature and history

The acronym "TOI" refers to stars and exoplanets studied by TESS, and is short for: "Transiting Exoplanet Survey Satellite Object of Interest".

Stellar characteristics

TOI-700 is a red dwarf of spectral class M (much redder, cooler, and dimmer than the sun) that is 40% the mass, 40% the radius and 55% of the temperature of the Sun. [6] The star is bright with low levels of stellar activity. Over the 11 sectors observed with TESS, the star does not show a single white-light flare. The low rotation rate is also an indicator of low stellar activity. [4]

Planetary system

The TOI-700 planetary system [7] [8]
Companion
(in order from star)
Mass Semimajor axis
(AU)
Orbital period
(days)
Eccentricity Inclination Radius
b<0.74  M🜨 0.0677±0.00119.977219+0.000041
0.000038
0.075+0.093
−0.054
89.60+0.27
−0.29
°
0.914+0.053
−0.049
  R🜨
c2.50±0.34  M🜨 0.0929±0.001516.051137±0.0000200.068+0.070
−0.049
88.903+0.071
−0.087
°
2.60+0.14
−0.13
  R🜨
e <1.16  M🜨 0.1340±0.002227.80978+0.00046
0.00040
0.059+0.057
−0.042
89.60+0.21
−0.16
°
0.953+0.089
−0.075
  R🜨
d 2.40+0.49
−0.52
  M🜨
0.1633±0.002737.42396+0.00039
0.00035
0.042+0.045
−0.030
89.80+0.12
−0.10
°
1.073+0.059
−0.054
  R🜨

Four exoplanets have been detected by TESS to be orbiting the host star TOI-700. All four exoplanets may be tidally locked to TOI-700. [6] [9]

Three papers describe the validation of the planetary system, the follow-up observations of TOI-700 d with the Spitzer Space Telescope and the characterization of TOI-700 d. [4] [10] [11]

The composition of planets b and d is more likely rocky and the composition of planet c is more likely similar to that of Neptune. [4] [8]

The two inner planets might have grown faster and accreted significant gaseous envelopes, but the outer planet formed more slowly and accreted less gas. The innermost planet may later have lost its envelope due to photoevaporation. Another scenario that could explain the arrangement of densities in this system is long-term planetary migration. Planet c might have migrated inwards, but this scenario is more plausible if future studies show that planet c is significantly more massive than planet b or d. [4]

Potentially habitable planets

TOI-700 d

Artwork of exoplanet TOI-700 d PIA23408-Exoplanet-TOI700d-20200106.jpg
Artwork of exoplanet TOI-700 d

TOI-700 d lies in the habitable zone. It receives 35 times more EUV photons than Earth, but also 50 times less than TRAPPIST-1 e. The host star has low stellar activity. The atmosphere of a planet with an Earth-like pressure would survive for longer than 1 Gyr. [4] Simulations of the planet have shown that TOI-700 d is a robust candidate for a habitable world. The simulated spectral feature depths from transmission spectra and the peak flux and variations from synthesized phase curves do not exceed 10 ppm. This will likely prohibit JWST from characterizing the atmosphere of TOI-700 d. [11]

TOI-700 e

TOI-700 e concept art TOI700e art.jpg
TOI-700 e concept art

In November 2021, a fourth possible planet, Earth-sized and receiving approximately 30% more flux from TOI-700 than Earth does from the Sun, was found at the inner edge of the habitable zone of TOI-700. [12] In January 2023 the existence of this planet, designated 700 e, was confirmed. [9]

Discovered in 2023, TOI-700 e is a terrestrial exoplanet that NASA claims to be an "earth-like" planet, with 95 percent of the Earth’s radius. Discovered by NASA's TESS (Transitioning Exoplanet Survey Satellite), TOI-700 e has a mass of about 0.818 Earths and takes 27.8 days to orbit once around its star. [13] The planet is in a habitable zone distance from the M-type star TOI-700 it orbits, leading NASA scientists to believe that there is potential for liquid water on its surface. Ten percent smaller than its neighboring planet TOI-700 d, both are at a distance from their sun to be considered habitable, however, TESS requires an additional year to acquire more data about the exoplanets. [14] Being one in only about a dozen habitable zone planets known, further research and data collection of the TOI-700 solar system is important for understanding Earth-like planets. [15]

Near orbital resonance

The system is near (but not in) orbital resonance: from planets b to d, period ratios are approximately 5:8, 4:7, 3:4.

TOI-700 multiplanetary system (video; 3:16)

See also

Notes

    Related Research Articles

    <span class="mw-page-title-main">Transiting Exoplanet Survey Satellite</span> NASA satellite of the Explorer program

    Transiting Exoplanet Survey Satellite (TESS) is a space telescope for NASA's Explorer program, designed to search for exoplanets using the transit method in an area 400 times larger than that covered by the Kepler mission. It was launched on 18 April 2018, atop a Falcon 9 launch vehicle and was placed into a highly elliptical 13.70-day orbit around the Earth. The first light image from TESS was taken on 7 August 2018, and released publicly on 17 September 2018.

    <span class="mw-page-title-main">Discoveries of exoplanets</span> Detecting planets located outside the Solar System

    An exoplanet is a planet located outside the Solar System. The first evidence of an exoplanet was noted as early as 1917, but was not recognized as such until 2016; no planet discovery has yet come from that evidence. What turned out to be the first detection of an exoplanet was published among a list of possible candidates in 1988, though not confirmed until 2003. The first confirmed detection came in 1992, with the discovery of terrestrial-mass planets orbiting the pulsar PSR B1257+12. The first confirmation of an exoplanet orbiting a main-sequence star was made in 1995, when a giant planet was found in a four-day orbit around the nearby star 51 Pegasi. Some exoplanets have been imaged directly by telescopes, but the vast majority have been detected through indirect methods, such as the transit method and the radial-velocity method. As of 24 July 2024, there are 7,026 confirmed exoplanets in 4,949 planetary systems, with 1007 systems having more than one planet. This is a list of the most notable discoveries.

    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">Planet Hunters</span> Citizen science project to find exoplanets

    Planet Hunters is a citizen science project to find exoplanets using human eyes. It does this by having users analyze data from the NASA Kepler space telescope and the NASA Transiting Exoplanet Survey Satellite. It was launched by a team led by Debra Fischer at Yale University, as part of the Zooniverse project.

    <span class="mw-page-title-main">TOI-700 d</span> Goldilocks terrestrial planet orbiting TOI-700

    TOI-700 d is a near-Earth-sized exoplanet, likely rocky, orbiting within the habitable zone of the red dwarf TOI-700, the outermost planet within the system. It is located roughly 101.4 light-years (31.1 pc) away from Earth in the constellation of Dorado. The exoplanet is the first Earth-sized exoplanet in the habitable zone discovered by the Transiting Exoplanet Survey Satellite (TESS).

    <span class="mw-page-title-main">TOI-1338</span> Binary star system in the constellation Pictor

    TOI-1338 is a binary star system located in the constellation Pictor, about 1,320 light-years from Earth. It is orbited by two known circumbinary planets, TOI-1338 b, discovered by the Transiting Exoplanet Survey Satellite (TESS) and BEBOP-1c, discovered by the Binaries Escorted By Orbiting Planets project.

    <span class="mw-page-title-main">Kepler-1649c</span> Earth-size exoplanet orbiting Kepler-1649

    Kepler-1649c is an Earth-sized exoplanet, likely rocky, orbiting within the habitable zone of the red dwarf star Kepler-1649, the outermost planet of the planetary system discovered by Kepler’s space telescope. It is located about 301 light-years (92 pc) away from Earth, in the constellation of Cygnus.

    K2-315b is an exoplanet located 185.3 light years away from Earth in the southern zodiac constellation Libra. It orbits the red dwarf K2-315.

    <span class="mw-page-title-main">Kepler-560b</span> Extrasolar planet

    Kepler-560b, or more correctly Kepler-560 Bb, is a confirmed exoplanet orbiting the secondary star of the binary star system Kepler-560. It is only 287 light-years away. Though not listed in the Habitable Exoplanets Catalog, one study gives the planet an 85% chance of being in the habitable zone.

    <span class="mw-page-title-main">Kepler-1638</span> G-type star in the constellation Cygnus

    Kepler-1638 is a G-type main-sequence star located about 5,000 light years away in the constellation of Cygnus. One known exoplanet has been found orbiting the star: Kepler-1638b.As of January 2021, Kepler-1638 is the farthest star with a known exoplanet orbiting in the habitable zone.

    L 98-59 is a bright M dwarf star, located in the constellation of Volans, at a distance of 10.608 parsecs, as measured by the Gaia spacecraft.

    HIP 67522 b is a hot Jupiter exoplanet orbiting the G-type star HIP 67522, located approximately 415 light-years from Earth in the constellation Centaurus, discovered using the Transiting Exoplanet Survey Satellite (TESS). It is currently the youngest hot Jupiter discovered, at an age of only 17 million years; it is also one of the youngest transiting planets of any type, and one of only four others less than 100 million years old to have the angle between its orbit and its host star's rotation measured, at 5.8+2.8
    −5.7
    degrees. This planet, in turn, may help in knowing how other hot Jupiters form.

    <span class="mw-page-title-main">TOI-2180 b</span> Jovian-sized exoplanet orbiting TOI-2180

    TOI-2180 b is a giant exoplanet orbiting the G-type star TOI-2180, also known as HD 238894. It was discovered with the help of the Transiting Exoplanet Survey Satellite and is currently the exoplanet with the longest orbital period TESS was able to uncover. TOI-2180 b orbits its host star every 260.16 days.

    <span class="mw-page-title-main">TOI-700 e</span> Earth-size exoplanet in Dorado

    TOI-700 e is the second outermost known exoplanet orbiting TOI-700, a red dwarf star in the constellation of Dorado.

    References

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