A multi-planetary system orbiting the early-M dwarf TOI-1238

Context. Planets orbiting low-mass stars such as M dwarfs are now considered a cornerstone in the search for planets with the potential to harbour life. GJ 273 is a planetary system orbiting an M dwarf only 3.75 pc away, which is composed of two confirmed planets, GJ 273b and GJ 273c, and two promising candidates, GJ 273d and GJ 273e. Planet GJ 273b resides in the habitable zone. Currently, due to a lack of observed planetary transits, only the minimum masses of the planets are known: Mb sin ib = 2.89 M⊕, Mc sin ic = 1.18 M⊕, Md sin id = 10.80 M⊕, and Me sin ie = 9.30 M⊕. Despite its interesting character, the GJ 273 planetary system has been poorly studied thus far. Aims. We aim to precisely determine the physical parameters of the individual planets, in particular, to break the mass–inclination degeneracy to accurately determine the mass of the planets. Moreover, we present a thorough characterisation of planet GJ 273b in terms of its potential habitability. Methods. First, we explored the planetary formation and hydration phases of GJ 273 during the first 100 Myr. Secondly, we analysed the stability of the system by considering both the two- and four-planet configurations. We then performed a comparative analysis between GJ 273 and the Solar System and we searched for regions in GJ 273 which may harbour minor bodies in stable orbits, that is, the main asteroid belt and Kuiper belt analogues. Results. From our set of dynamical studies, we find that the four-planet configuration of the system allows us to break the mass–inclination degeneracy. From our modelling results, the masses of the planets are unveiled as: 2.89 ≤ Mb ≤ 3.03 M⊕, 1.18 ≤ Mc ≤ 1.24 M⊕, 10.80 ≤ Md ≤ 11.35 M⊕, and 9.30 ≤ Me ≤ 9.70 M⊕. These results point to a system that is likely to be composed of an Earth-mass planet, a super-Earth and two mini-Neptunes. Based on planetary formation models, we determine that GJ 273b is likely an efficient water captor while GJ 273c is probably a dry planet. We find that the system may have several stable regions where minor bodies might reside. Collectively, these results are used to offer a comprehensive discussion about the habitability of GJ 273b.

Download Full-text

A PLANETARY SYSTEM AROUND THE NEARBY M DWARF GJ 667C WITH AT LEAST ONE SUPER-EARTH IN ITS HABITABLE ZONE

The Astrophysical Journal ◽

10.1088/2041-8205/751/1/l16 ◽

2012 ◽

Vol 751 (1) ◽

pp. L16 ◽

Cited By ~ 97

Author(s):

Guillem Anglada-Escudé ◽

Pamela Arriagada ◽

Steven S. Vogt ◽

Eugenio J. Rivera ◽

R. Paul Butler ◽

...

Keyword(s):

Planetary System ◽

Habitable Zone ◽

M Dwarf

Download Full-text

ISPY – NaCo Imaging Survey for Planets around Young stars

Astronomy and Astrophysics ◽

10.1051/0004-6361/201935146 ◽

2019 ◽

Vol 627 ◽

pp. A77 ◽

Cited By ~ 4

Author(s):

Arianna Musso Barcucci ◽

Ralf Launhardt ◽

Grant M. Kennedy ◽

Henning Avenhaus ◽

Stefan S. Brems ◽

...

Keyword(s):

Planetary System ◽

Young Stars ◽

Relative Importance ◽

Additional Information ◽

The Third ◽

Low Mass ◽

Formation And Evolution ◽

The Moment ◽

M Dwarf ◽

Disc Size

Context. The interaction between low-mass companions and the debris discs they reside in is still not fully understood. A debris disc can evolve due to self-stirring, a process in which planetesimals can excite their neighbours to the point of destructive collisions. In addition, the presence of a companion could further stir the disc (companion-stirring). Additional information is necessary to understand this fundamental step in the formation and evolution of a planetary system, and at the moment of writing only a handful of systems are known where a companion and a debris disc have both been detected and studied at the same time. Aims. Our primary goal is to augment the sample of these systems and to understand the relative importance between self-stirring and companion-stirring. Methods. In the course of the VLT/NaCo Imaging Survey for Planets around Young stars (ISPY), we observed HD 193571, an A0 debris disc hosting star at a distance of 68 pc with an age between ∼60 and 170 Myr. We obtained two sets of observations in L′ band and a third epoch in H band using the GPI instrument at Gemini-South. Results. A companion was detected in all three epochs at a projected separation of ∼11 au (∼0.17″), and co-motion was confirmed through proper motion analysis. Given the inferred disc size of 120 au, the companion appears to reside within the gap between the host star and the disc. Comparison between the L′ and H band magnitude and evolutionary tracks suggests a mass of ∼0.31 − 0.39 M⊙. Conclusions. We discovered a previously unknown M-dwarf companion around HD 193571, making it the third low-mass stellar object discovered within a debris disc. A comparison to self- and companion-stirring models suggests that the companion is likely responsible for the stirring of the disc.

Download Full-text

The CARMENES search for exoplanets around M dwarfs

Astronomy and Astrophysics ◽

10.1051/0004-6361/202037867 ◽

2020 ◽

Vol 642 ◽

pp. A173 ◽

Cited By ~ 1

Author(s):

G. Nowak ◽

R. Luque ◽

H. Parviainen ◽

E. Pallé ◽

K. Molaverdikhani ◽

...

Keyword(s):

Planetary System ◽

Outer Planet ◽

Planetary Formation ◽

Atmospheric Models ◽

M Dwarfs ◽

Ideal Object ◽

Transiting Planets ◽

Short Period ◽

Iron Abundance ◽

M Dwarf

We present the discovery and characterisation of two transiting planets observed by the Transiting Exoplanet Survey Satellite (TESS) orbiting the nearby (d⋆ ≈ 22 pc), bright (J ≈ 9 mag) M3.5 dwarf LTT 3780 (TOI–732). We confirm both planets and their association with LTT 3780 via ground-based photometry and determine their masses using precise radial velocities measured with the CARMENES spectrograph. Precise stellar parameters determined from CARMENES high-resolution spectra confirm that LTT 3780 is a mid-M dwarf with an effective temperature of Teff = 3360 ± 51 K, a surface gravity of log g⋆ = 4.81 ± 0.04 (cgs), and an iron abundance of [Fe/H] = 0.09 ± 0.16 dex, with an inferred mass of M⋆ = 0.379 ± 0.016M⊙ and a radius of R⋆ = 0.382 ± 0.012R⊙. The ultra-short-period planet LTT 3780 b (Pb = 0.77 d) with a radius of 1.35−0.06+0.06 R⊕, a mass of 2.34−0.23+0.24 M⊕, and a bulk density of 5.24−0.81+0.94 g cm−3 joins the population of Earth-size planets with rocky, terrestrial composition. The outer planet, LTT 3780 c, with an orbital period of 12.25 d, radius of 2.42−0.10+0.10 R⊕, mass of 6.29−0.61+0.63 M⊕, and mean density of 2.45−0.37+0.44 g cm−3 belongs to the population of dense sub-Neptunes. With the two planets located on opposite sides of the radius gap, this planetary system is anexcellent target for testing planetary formation, evolution, and atmospheric models. In particular, LTT 3780 c is an ideal object for atmospheric studies with the James Webb Space Telescope (JWST).

Download Full-text

The CARMENES search for exoplanets around M dwarfs

Astronomy and Astrophysics ◽

10.1051/0004-6361/201936987 ◽

2020 ◽

Vol 638 ◽

pp. A16

Author(s):

T. Trifonov ◽

M. H. Lee ◽

M. Kürster ◽

Th. Henning ◽

E. Grishin ◽

...

Keyword(s):

Planetary System ◽

Stable Region ◽

M Dwarfs ◽

Orbital Parameters ◽

Orbital Decay ◽

Secular Theory ◽

Orbital Configuration ◽

Large Phase ◽

M Dwarf

Context. GJ 1148 is an M-dwarf star hosting a planetary system composed of two Saturn-mass planets in eccentric orbits with periods of 41.38 and 532.02 days. Aims. We reanalyze the orbital configuration and dynamics of the GJ 1148 multi-planetary system based on new precise radial velocity measurements taken with CARMENES. Methods. We combined new and archival precise Doppler measurements from CARMENES with those available from HIRES for GJ 1148 and modeled these data with a self-consistent dynamical model. We studied the orbital dynamics of the system using the secular theory and direct N-body integrations. The prospects of potentially habitable moons around GJ 1148 b were examined. Results. The refined dynamical analyses show that the GJ 1148 system is long-term stable in a large phase-space of orbital parameters with an orbital configuration suggesting apsidal alignment, but not in any particular high-order mean-motion resonant commensurability. GJ 1148 b orbits inside the optimistic habitable zone (HZ). We find only a narrow stability region around the planet where exomoons can exist. However, in this stable region exomoons exhibit quick orbital decay due to tidal interaction with the planet. Conclusions. The GJ 1148 planetary system is a very rare M-dwarf planetary system consisting of a pair of gas giants, the inner of which resides in the HZ. We conclude that habitable exomoons around GJ 1148 b are very unlikely to exist.

Download Full-text

Planetary system around the nearby M dwarf GJ 357 including a transiting, hot, Earth-sized planet optimal for atmospheric characterization

Astronomy and Astrophysics ◽

10.1051/0004-6361/201935801 ◽

2019 ◽

Vol 628 ◽

pp. A39 ◽

Cited By ~ 37

Author(s):

R. Luque ◽

E. Pallé ◽

D. Kossakowski ◽

S. Dreizler ◽

J. Kemmer ◽

...

Keyword(s):

Planetary System ◽

Rotation Period ◽

Archival Data ◽

Habitable Zone ◽

Minimum Mass ◽

Velocity Signal ◽

Planetary Mass ◽

Using Data ◽

M Dwarf ◽

Prime Target

We report the detection of a transiting Earth-size planet around GJ 357, a nearby M2.5 V star, using data from the Transiting Exoplanet Survey Satellite (TESS). GJ 357 b (TOI-562.01) is a transiting, hot, Earth-sized planet (Teq = 525 ± 11 K) with a radius of Rb = 1.217 ± 0.084 R⊕ and an orbital period of Pb = 3.93 d. Precise stellar radial velocities from CARMENES and PFS, as well as archival data from HIRES, UVES, and HARPS also display a 3.93-day periodicity, confirming the planetary nature and leading to a planetary mass of Mb = 1.84 ± 0.31 M⊕. In addition to the radial velocity signal for GJ 357 b, more periodicities are present in the data indicating the presence of two further planets in the system: GJ 357 c, with a minimum mass of Mc = 3.40 ± 0.46 M⊕ in a 9.12 d orbit, and GJ 357 d, with a minimum mass of Md = 6.1 ± 1.0 M⊕ in a 55.7 d orbit inside the habitable zone. The host is relatively inactive and exhibits a photometric rotation period of Prot = 78 ± 2 d. GJ 357 b isto date the second closest transiting planet to the Sun, making it a prime target for further investigations such as transmission spectroscopy. Therefore, GJ 357 b represents one of the best terrestrial planets suitable for atmospheric characterization with the upcoming JWST and ground-based ELTs.

Download Full-text

Annual gazetteer of planetary nomenclature, Intenationl astronomical union, working group for planetary system nomenclature

Open-File Report ◽

10.3133/ofr84692 ◽

1986 ◽

Cited By ~ 1

Author(s):

Harold Masursky ◽

Kaare Aksnes ◽

G.E. Hunt ◽

M.Y. Marov ◽

P.M. Millman ◽

...

Keyword(s):

Working Group ◽

Planetary System

Download Full-text

Drifting Through a Planetary System

10.1093/oso/9780198799894.003.0006 ◽

2018 ◽

Author(s):

Karel Schrijver

Keyword(s):

Seventeenth Century ◽

Solar System ◽

Virtual Worlds ◽

Planetary System ◽

System P ◽

History Of ◽

Or Team ◽

Water Contents

This chapter describes how the first found exoplanets presented puzzles: they orbited where they should not have formed or where they could not have survived the death of their stars. The Solar System had its own puzzles to add: Mars is smaller than expected, while Venus, Earth, and Mars had more water—at least at one time—than could be understood. This chapter shows how astronomers worked through the combination of these puzzles: now we appreciate that planets can change their orbits, scatter water-bearing asteroids about, steal material from growing planets, or team up with other planets to stabilize their future. The special history of Jupiter and Saturn as a pair bringing both destruction and water to Earth emerged from the study of seventeenth-century resonant clocks, from the water contents of asteroids, and from experiments with supercomputers imposing the laws of physics on virtual worlds.

Download Full-text

DESTINY: Database for the Effects of STellar encounters on dIsks and plaNetary sYstems

Computational Astrophysics and Cosmology ◽

10.1186/s40668-019-0030-3 ◽

2019 ◽

Vol 6 (1) ◽

Cited By ~ 2

Author(s):

Asmita Bhandare ◽

Susanne Pfalzner

Keyword(s):

Planetary System ◽

Planetary Systems ◽

Gravitational Effect ◽

Parameter Study ◽

Orbital Inclination ◽

Particle Properties ◽

Disk Size ◽

Stellar Group ◽

Cluster Environment ◽

Parabolic Orbits

Abstract Most stars form as part of a stellar group. These young stars are mostly surrounded by a disk from which potentially a planetary system might form. Both, the disk and later on the planetary system, may be affected by the cluster environment due to close fly-bys. The here presented database can be used to determine the gravitational effect of such fly-bys on non-viscous disks and planetary systems. The database contains data for fly-by scenarios spanning mass ratios between the perturber and host star from 0.3 to 50.0, periastron distances from 30 au to 1000 au, orbital inclination from 0∘ to 180∘ and angle of periastron of 0∘, 45∘ and 90∘. Thus covering a wide parameter space relevant for fly-bys in stellar clusters. The data can either be downloaded to perform one’s own diagnostics like for e.g. determining disk size, disk mass, etc. after specific encounters, obtain parameter dependencies or the different particle properties can be visualized interactively. Currently the database is restricted to fly-bys on parabolic orbits, but it will be extended to hyperbolic orbits in the future. All of the data from this extensive parameter study is now publicly available as DESTINY.

Download Full-text