scholarly journals A terrestrial planet in a ~1-AU orbit around one member of a ∼15-AU binary

Science ◽  
2014 ◽  
Vol 345 (6192) ◽  
pp. 46-49 ◽  
Author(s):  
A. Gould ◽  
A. Udalski ◽  
I.-G. Shin ◽  
I. Porritt ◽  
J. Skowron ◽  
...  
Keyword(s):  
Binary Systems ◽  
Planet Formation ◽  
Binary Star ◽  
Terrestrial Planet ◽  
Search Strategies ◽  
The Sun ◽  
Star System ◽  
Low Mass ◽  
Formation And Evolution ◽  
Binary Star System

Using gravitational microlensing, we detected a cold terrestrial planet orbiting one member of a binary star system. The planet has low mass (twice Earth’s) and lies projected at ~0.8 astronomical units (AU) from its host star, about the distance between Earth and the Sun. However, the planet’s temperature is much lower, <60 Kelvin, because the host star is only 0.10 to 0.15 solar masses and therefore more than 400 times less luminous than the Sun. The host itself orbits a slightly more massive companion with projected separation of 10 to 15 AU. This detection is consistent with such systems being very common. Straightforward modification of current microlensing search strategies could increase sensitivity to planets in binary systems. With more detections, such binary-star planetary systems could constrain models of planet formation and evolution.

scholarly journals Planet Formation in Binary Systems

2001 ◽  
Vol 200 ◽  
pp. 511-518 ◽  
Author(s):  
Wilhelm Kley
Keyword(s):  
Binary Systems ◽  
Main Sequence ◽  
Extrasolar Planets ◽  
Planet Formation ◽  
Binary Star ◽  
Stellar Systems ◽  
Star System ◽  
Solar Type ◽  
Tidal Torques ◽  
Binary Star System

Among the 50 discovered extrasolar planets orbiting main-sequence solar type stars only three are confirmed to be in a binary star system. However, the majority of stars seem to form in binary or even multiple stellar systems. Standard planet formation scenarios consider the creation of planets or planetary systems only for isolated solitary stars. The presence of a companion creates tidal torques on the protoplanetary disk, which may influence the formation process of planets in disks. In this contribution the consequences of the companion's perturbation on the formation scenario of planets is briefly discussed.

scholarly journals Impact flux of asteroids and water transport to the habitable zone in binary star systems

2014 ◽  
Vol 9 (S310) ◽  
pp. 86-87
Author(s):  
D. Bancelin ◽  
E. Pilat-Lohinger ◽  
S. Eggl ◽  
R. Dvorak
Keyword(s):  
Binary Star ◽  
Stellar System ◽  
Terrestrial Planet ◽  
Solar Neighborhood ◽  
Planetary Motion ◽  
Habitable Zone ◽  
Star System ◽  
Single Star ◽  
Multiple Systems ◽  
Binary Star System

AbstractBy now, observations of exoplanets have found more than 50 binary star systems hosting 71 planets. We expect these numbers to increase as more than 70% of the main sequence stars in the solar neighborhood are members of binary or multiple systems. The planetary motion in such systems depends strongly on both the parameters of the stellar system (stellar separation and eccentricity) and the architecture of the planetary system (number of planets and their orbital behaviour). In case a terrestrial planet moves in the so-called habitable zone (HZ) of its host star, the habitability of this planet depends on many parameters. A crucial factor is certainly the amount of water. We investigate in this work the transport of water from beyond the snow-line to the HZ in a binary star system and compare it to a single star system.

scholarly journals Commission 26: Double and Multiple Stars (Etoiles Doubles Et Multiples)

2000 ◽  
Vol 24 (1) ◽  
pp. 186-189
Author(s):  
H. Zinnecker ◽  
C. Scarfe ◽  
C. Allen ◽  
T. Armstrong ◽  
W. Hartkopf ◽  
...  
Keyword(s):  
San Francisco ◽  
Large Scale ◽  
Binary Systems ◽  
Extrasolar Planets ◽  
Binary Star ◽  
The Sun ◽  
Double And Multiple Stars ◽  
Nearby Stars ◽  
Solar Type ◽  
Low Mass

This triennial report (1996-1999) reviews the subject from a somewhat personal angle, mostly related to binary star formation and young binary star populations – a subject whose time had come in the early 1990s and is now in full swing.Many astronomers have searched for binary systems among main-sequence stars, and two large-scale surveys published in 1991 and 1992 have already become classics. Well before they became famous for finding extrasolar planets (see below), observing teams led by Michel Mayor (Geneva Observatory) and Geoffrey Marcy (San Francisco State Univ., now Univ. of Calif, at Berkeley) spent many years searching for low-mass stellar companions of nearby stars. The late Antoine Duquennoy and Mayor surveyed all solar-type dwarfs (spectral types F7 through G9) within 20 pc of the Sun, while Debra Fischer and Marcy studied stars with somewhat lower mass (M dwarfs) slightly nearer to the Sun.

scholarly journals The Formation of Population III Binaries from Cosmological Initial Conditions

Science ◽  
2009 ◽  
Vol 325 (5940) ◽  
pp. 601-605 ◽  
Author(s):  
Matthew J. Turk ◽  
Tom Abel ◽  
Brian O'Shea
Keyword(s):  
Molecular Hydrogen ◽  
Initial Conditions ◽  
Binary Star ◽  
The Sun ◽  
Star System ◽  
Mass Ratio ◽  
Gas Reservoir ◽  
First Stars ◽  
Hydrogen Lines ◽  
Binary Star System

Previous high-resolution cosmological simulations predicted that the first stars to appear in the early universe were very massive and formed in isolation. Here, we discuss a cosmological simulation in which the central 50 M⊙ (where M⊙ is the mass of the Sun) clump breaks up into two cores having a mass ratio of two to one, with one fragment collapsing to densities of 10−8 grams per cubic centimeter. The second fragment, at a distance of ~800 astronomical units, is also optically thick to its own cooling radiation from molecular hydrogen lines but is still able to cool via collision-induced emission. The two dense peaks will continue to accrete from the surrounding cold gas reservoir over a period of ~105 years and will likely form a binary star system.

scholarly journals Multiplanet disc interactions in binary systems

2019 ◽  
Vol 491 (4) ◽  
pp. 5351-5360 ◽  
Author(s):  
Alessia Franchini ◽  
Rebecca G Martin ◽  
Stephen H Lubow
Keyword(s):  
Binary Systems ◽  
Large Range ◽  
Average Rate ◽  
Binary Star ◽  
Orbital Plane ◽  
High Mass ◽  
Star System ◽  
Hydrodynamical Simulations ◽  
Binary Star System

ABSTRACT We investigate the evolution of a multiplanet–disc system orbiting one component of a binary star system. The planet–disc system is initially coplanar but misaligned to the binary orbital plane. The planets are assumed to be giants that open gaps in the disc. We first study the role of the disc in shaping the mutual evolution of the two planets using a secular model for low initial tilt. In general, we find that the planets and the disc do not remain coplanar, in agreement with previous work on the single planet case. Instead, the planets and the disc undergo tilt oscillations. A high-mass disc between the two planets causes the planets and the disc to nodally precess at the same average rate but they are generally misaligned. The amplitude of the tilt oscillations between the planets is larger while the disc is present. We then consider higher initial tilts using hydrodynamical simulations and explore the possibility of the formation of eccentric Kozai–Lidov (KL) planets. We find that the inner planet’s orbit undergoes eccentricity growth for a large range of disc masses and initial misalignments. For a low disc mass and large initial misalignment, both planets and the disc can undergo KL oscillations. Furthermore, we find that sufficiently massive discs can cause the inner planet to increase its inclination beyond 90° and therefore to orbit the binary in a retrograde fashion. The results have important implications for the explanation of very eccentric planets and retrograde planets observed in multiplanet systems.

scholarly journals Terrestrial planet formation in extra-solar planetary systems

2007 ◽  
Vol 3 (S249) ◽  
pp. 233-250 ◽  
Author(s):  
Sean N. Raymond
Keyword(s):  
Final Stage ◽  
Planet Formation ◽  
Giant Planet ◽  
Terrestrial Planet ◽  
Circumstellar Disks ◽  
Giant Planets ◽  
Terrestrial Planets ◽  
Low Mass Stars ◽  
Low Mass ◽  
Rocky Planets

AbstractTerrestrial planets form in a series of dynamical steps from the solid component of circumstellar disks. First, km-sized planetesimals form likely via a combination of sticky collisions, turbulent concentration of solids, and gravitational collapse from micron-sized dust grains in the thin disk midplane. Second, planetesimals coalesce to form Moon- to Mars-sized protoplanets, also called “planetary embryos”. Finally, full-sized terrestrial planets accrete from protoplanets and planetesimals. This final stage of accretion lasts about 10-100 Myr and is strongly affected by gravitational perturbations from any gas giant planets, which are constrained to form more quickly, during the 1-10 Myr lifetime of the gaseous component of the disk. It is during this final stage that the bulk compositions and volatile (e.g., water) contents of terrestrial planets are set, depending on their feeding zones and the amount of radial mixing that occurs. The main factors that influence terrestrial planet formation are the mass and surface density profile of the disk, and the perturbations from giant planets and binary companions if they exist. Simple accretion models predicts that low-mass stars should form small, dry planets in their habitable zones. The migration of a giant planet through a disk of rocky bodies does not completely impede terrestrial planet growth. Rather, “hot Jupiter” systems are likely to also contain exterior, very water-rich Earth-like planets, and also “hot Earths”, very close-in rocky planets. Roughly one third of the known systems of extra-solar (giant) planets could allow a terrestrial planet to form in the habitable zone.

scholarly journals Characterisation of exoplanet host stars: A window into planet formation

2017 ◽  
Vol 12 (S330) ◽  
pp. 369-376 ◽  
Author(s):  
Nuno C. Santos
Keyword(s):  
Planet Formation ◽  
The Sun ◽  
The Future ◽  
The Galaxy ◽  
Crucial Information ◽  
Formation And Evolution ◽  
Host Stars

AbstractThe detection of thousands of planets orbiting stars other than the Sun has shown that planets are common throughout the Galaxy. However, the diversity of systems found has also raised many questions regarding the process of planet formation and evolution. Interestingly, but perhaps not unexpectedly, crucial information to constraint the planet formation models comes from the analysis of the planet-host stars. In this talk I will review why it is so important to study and understand the stars when finding and characterising exoplanets. I will then present some of the most relevant star-planet relations found to date, and how they are helping us to understand planet formation and evolution. I will end with a presentation of the future steps in this field, including what Gaia will bring to help constrain the properties of planet-host stars, as well as to the star-planet connection.

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