Planets around M Giants: HD 208527 and HD 220074

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Planets around M Giants: HD 208527 and HD 220074

Post by Sirius_Alpha on 11th November 2012, 9:30 pm

Planetary companions orbiting M giants HD 208527 and HD 220074
http://arxiv.org/abs/1211.2051

Aims. The purpose of the present study is to research the origin of planetary companions by using a precise radial velocity (RV) survey.
Methods. The high-resolution spectroscopy of the fiber-fed Bohyunsan Observatory Echelle Spectrograph (BOES) at Bohyunsan Optical Astronomy Observatory (BOAO) is used from September 2008 to June 2012.
Results. We report the detection of two exoplanets in orbit around HD 208527 and HD 220074 exhibiting periodic variations in RV of 875.5 +/- 5.8 and 672.1 +/- 3.7 days. The RV variations are not apparently related to the surface inhomogeneities and a Keplerian motion of the planetary companion is the most likely explanation. Assuming possible stellar masses of 1.6 +/- 0.4 and 1.2 +/- 0.3 M_Sun, we obtain the minimum masses for the exoplanets of 9.9 +/- 1.7 and 11.1 +/- 1.8 M_Jup around HD 208527 and HD 220074 with an orbital semi-major axis of 2.1 +/- 0.2 and 1.6 +/- 0.1 AU and an eccentricity of 0.08 and 0.14, respectively. We also find that the previously known spectral classification of HD 208527 and HD 220074 was in error: Our new estimation of stellar parameters suggest that both HD 208527 and HD 220074 are M giants. Therefore, HD 208527 and HD 220074 are so far the first candidate M giants to harbor a planetary companion.

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Re: Planets around M Giants: HD 208527 and HD 220074

Post by Edasich on 12th November 2012, 5:08 am

I hope astrometry may confirm them as such since M giants use to host stellar companions.
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Re: Planets around M Giants: HD 208527 and HD 220074

Post by Lazarus on 12th November 2012, 2:11 pm

Both misidentified as K-dwarfs... huh.
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Re: Planets around M Giants: HD 208527 and HD 220074

Post by Sirius_Alpha on 12th November 2012, 3:24 pm

HD 220074 was listed in SIMBAD as M2III at least.

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Re: Planets around M Giants: HD 208527 and HD 220074

Post by Edasich on 12th November 2012, 4:17 pm

I also hope the planets don't turn out being low-mass stars. The stellar rotation period of each star is close to orbital periods.
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Re: Planets around M Giants: HD 208527 and HD 220074

Post by Szaniu on 3rd December 2012, 5:06 pm

So these planets are not confirmed. Right? EPE is so confusing Neutral.

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Re: Planets around M Giants: HD 208527 and HD 220074

Post by Sirius_Alpha on 3rd December 2012, 5:24 pm

They are indeed confirmed candidates. I'm not sure what you mean about the EPE. It has pages for both:
HD 208527 b
HD 220074 b

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Re: Planets around M Giants: HD 208527 and HD 220074

Post by Szaniu on 3rd December 2012, 5:45 pm

Completely misunderstood the abstract Smile. Sorry.

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