YZ Cet - Very nearby (3.6 pc) M dwarf with Earth-mass planets

Go down

YZ Cet - Very nearby (3.6 pc) M dwarf with Earth-mass planets

Post by Sirius_Alpha on 13th August 2017, 8:24 pm

The HARPS search for southern extra-solar planets XLII. A system of Earth-mass planets around the nearby M dwarf YZ Cet
https://arxiv.org/abs/1708.03336

Exoplanet surveys have shown that systems with multiple low-mass planets on compact orbits are common. Except for few cases, however, the masses of these planets are generally unknown. At the very end of the main sequence, host stars have the lowest mass and hence offer the largest reflect motion for a given planet. In that context, we monitored the low-mass (0.13Msun) M dwarf YZ Cet (GJ 54.1, HIP 5643) intensively and obtained both radial velocities and stellar-activity indicators derived from both spectroscopy and photometry. We find strong evidence that it is orbited by at least three planets in compact orbits (P=1.97, 3.06, 4.66 days), with the inner two near a 2:3 mean-motion resonance. The minimum masses are comparable to that of Earth (Msini=0.75+-0.13, 0.98+-0.14, and 1.14+-0.17 Mearth) and also the lowest masses measured by radial velocity so far. We note the possibility for an even lower-mass, fourth planet with Msini=0.472+-0.096 Mearth at P=1.04 days. An n-body dynamical model is used to put further constraints on the system parameters. At 3.6 parsecs, YZ Cet is the nearest multi-planet system detected to date.

_________________
Caps Lock: Cruise control for 'Cool'!
avatar
Sirius_Alpha
Admin
Admin

Number of posts : 3700
Location : Earth
Registration date : 2008-04-06

View user profile http://solar-flux.forumandco.com/

Back to top Go down

Re: YZ Cet - Very nearby (3.6 pc) M dwarf with Earth-mass planets

Post by tommi59 on 14th August 2017, 3:04 am

Nice good chances to detect transits especially for unconfirmed candidate.
avatar
tommi59
Jovian
Jovian

Number of posts : 562
Age : 40
Location : Baile Atha Cliath
Registration date : 2010-07-31

View user profile

Back to top Go down

Re: YZ Cet - Very nearby (3.6 pc) M dwarf with Earth-mass planets

Post by Edasich on 14th August 2017, 4:29 am

Great find. More exoplanets in the Solar Neighborhood. Very Happy
avatar
Edasich
dM star
dM star

Number of posts : 1548
Location : Tau Ceti g - Mid Latitudes
Registration date : 2008-06-02

View user profile

Back to top Go down

Re: YZ Cet - Very nearby (3.6 pc) M dwarf with Earth-mass planets

Post by Sirius_Alpha on 31st August 2017, 6:57 pm

An estimate of the age of the star
http://www.astronomerstelegram.org/?read=10678

_________________
Caps Lock: Cruise control for 'Cool'!
avatar
Sirius_Alpha
Admin
Admin

Number of posts : 3700
Location : Earth
Registration date : 2008-04-06

View user profile http://solar-flux.forumandco.com/

Back to top Go down

Re: YZ Cet - Very nearby (3.6 pc) M dwarf with Earth-mass planets

Post by Sirius_Alpha on 22nd August 2018, 8:42 pm

Aliasing in the Radial Velocities of YZ Ceti: An Ultra-Short Period for YZ Ceti c?
https://arxiv.org/abs/1808.07059

Mid-late M stars are opportunistic targets for the study of low-mass exoplanets in transit because of the high planet-to-star radius ratios of their planets. Recent studies of such stars have shown that, like their early-M counterparts, they often host multi-resonant networks of small planets. Here, we reanalyze radial velocity measurements of YZ Ceti, an active M4 dwarf for which the HARPS exoplanet survey recently discovered three exoplanets on short-period (P = 4.66, 3.06, 1.97 days) orbits. Our analysis finds that the orbital periods of the inner two planets cannot be uniquely determined using the published HARPS velocities. In particular, it appears likely that the 3.06-day period of YZ Ceti c is an alias, and that its true period is 0.75 days. If so, the revised minimum mass of this planet is less than 0.6 Earth masses, and its geometric transit probability increases to 10%. We encourage additional observations to determine the true periods of YZ Ceti b and c, and suggest a search for transits at the 0.75-day period in TESS lightcurves.

_________________
Caps Lock: Cruise control for 'Cool'!
avatar
Sirius_Alpha
Admin
Admin

Number of posts : 3700
Location : Earth
Registration date : 2008-04-06

View user profile http://solar-flux.forumandco.com/

Back to top Go down

Re: YZ Cet - Very nearby (3.6 pc) M dwarf with Earth-mass planets

Post by Sponsored content


Sponsored content


Back to top Go down

Back to top


 
Permissions in this forum:
You cannot reply to topics in this forum