Jovian planets around 14 And, 81 Cet, 6 Lyn.

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Jovian planets around 14 And, 81 Cet, 6 Lyn.

Post by Sirius_Alpha on 2nd July 2008, 9:57 pm

Three new planets around intermediate-mass evolved stars. HD 167042 b, however, has been known.

Planetary Companions to Evolved Intermediate-Mass Stars: 14 Andromedae, 81 Ceti, 6 Lyncis, and HD 167042
http://arxiv.org/abs/0807.0268
abstract wrote:We report on the detection of four extrasolar planets orbiting evolved intermediate-mass stars from a precise Doppler survey of G and K giants at Okayama Astrophysical Observatory. All of the host stars are considered to be formerly early F-type or A-type dwarfs when they were on the main sequence. 14 And (K0 III) is a clump giant with a mass of 2.2 M_solar and has a planet of minimum mass m_2sin i=4.8 M_Jup in a nearly circular orbit with a 186 day period. This is one of the innermost planets around evolved intermediate-mass stars and such planets have only been discovered in clump giants. 81 Cet (G5 III) is a clump giant with 2.4 M_solar hosting a planet of m_2sin i=5.3 M_Jup in a 953 day orbit with an eccentricity of e=0.21. 6 Lyn (K0 IV) is a less evolved subgiant with 1.7 M_solar and has a planet of m_2sin i=2.4 M_Jup in a 899 day orbit with e=0.13. HD 167042 (K1 IV) is also a less evolved star with 1.5 M_solar hosting a planet of m_2sin i=1.6 M_Jup in a 418 day orbit with e=0.10. This planet was independently announced by Johnson et al. (2008, ApJ, 675, 784). All of the host stars have solar or sub-solar metallicity, which supports the lack of metal-rich tendency in planet-harboring giants in contrast to the case of dwarfs.


14 Andromedae b
Period = 185.84 days.
K = 100 m s^-1
e = 0
Omega = 0
Mass = 4.8 J
a = 0.83 AU

81 Ceti b
Period = 952.7 days
K = 62.8 m s^-1
e = 0.206
Omega = 175
Mass = 5.3 J
a = 2.5 AU

6 Lyncis b
Period = 899 days
K = 36.2 m s^-1
e = 0.134
Omega = 27
Mass = 2.4 J
a = 2.2 AU

HD 167042 b
Period = 417.6 days
K = 33.3 m s^-1
e = 0.101
Omega = 82
Mass = 1.6 J
a = 1.3 AU

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Re: Jovian planets around 14 And, 81 Cet, 6 Lyn.

Post by Edasich on 3rd July 2008, 5:58 am

That is good. These are all planets laying relatively farther away from host giants than other evolved star's companions.
Plus 81 Ceti is the first yellow giant known to host a planetary companion so far (well...after 18 Delphini ). Previous detections aimed K0-K2 giants, neither early nor later spectral types. cyclops

Still waiting a planet around a M giant or something Smile


HD 167042 b, however, has been known.

Indeed, but spectral type has been defined as K1IV, alike Epsilon Reticuli or Gamma Cephei (and now 6 Lyncis too) whereas HIPPARCOS classed it as K1III.
Moreover habitable zone keeps laying at 3.2 AUs though. sunny
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Re: Jovian planets around 14 And, 81 Cet, 6 Lyn.

Post by Lazarus on 5th July 2008, 8:31 am

Edasich wrote:Plus 81 Ceti is the first yellow giant known to host a planetary companion so far (well...after 18 Delphini ).

HD 104985, Xi Aquilae, Eta2 Hydri?
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Re: Jovian planets around 14 And, 81 Cet, 6 Lyn.

Post by Edasich on 5th July 2008, 8:58 am

HD 104985, Xi Aquilae, Eta2 Hydri?


Well, those have G8III spectral types, close to K0III. G5III is much earlier, close to G2. Rolling Eyes
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Re: Jovian planets around 14 And, 81 Cet, 6 Lyn.

Post by Sirius_Alpha on 5th July 2008, 12:15 pm

I think Edasich is going by colour as opposed to spectral types. G8III would probably look orangeish.

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Re: Jovian planets around 14 And, 81 Cet, 6 Lyn.

Post by Lazarus on 5th July 2008, 12:37 pm

In order of decreasing temperature...

18 Delphini - 4979 K (ref)
Eta2 Hydri - 4970 K (ref)
HD 104985 - 4877 K (ref)
81 Ceti - 4785 K (ref)
Xi Aquilae - 4780 K (ref)




Or in order of B-V (greater B-V means more red in color)

Eta2 Hydri - 0.931
18 Delphini - 0.934
81 Ceti - 1.021
Xi Aquilae - 1.023
HD 104985 - 1.029
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Re: Jovian planets around 14 And, 81 Cet, 6 Lyn.

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