G-K Giants Meeting22 Feb 2005

ESO Garching

Johny Setiawan

Max-Planck-Institut für Astronomie

The K giant‘s friends/fans (as I know)

Obs. Nacional + Univ. RioLicio da SilvaJ. Renan de Medeiros

ESO GarchingLuca PasquiniMichaela Döllinger

KIS-FreiburgOskar von der Lühe

MPIA-HeidelbergJohny SetiawanPatrick Weise, Florian Klotz

TLS-TautenburgArtie Hatzes

PadovaLeo Girardi

other collaborations

FEROS at 1.52m ESO Oct 1999 – Feb 2002

FEROS at 2.2m MPG/ESO Dec 2003 – Jun 2007? (run as secondary program in MPG GT)

Data acquisition (as I know)

observation gap Feb 2002 – Dec 2003 (few CORALIE measurements)

HERCULES at 1.0m MJO/NZ Dec 2004 – Jun 2007? (run as secondary program in complementary to PRIMA)

TLS spectrograph at 2m Tautenburg from ? – now ?

others (run in brazilian time ? other TLS time ?)

Method Messenger 102, 13

Substellar candidate HD 47536 b A&A 2003 398, L19

Multiple systems A&A 2004 421, 241

ASP 318, 2004, 283

First results A&A 2003 397, 1151

Extrasolar planets of K giants ESA SP-538 2004, 87

ESA SP-529 2004, 595

Chromospheric activity Cool Star Meeting 13

Substellar candidate HD 11977 b A&A 2005 submitted

Published results (2000 - now)

Some new results

Not yet published as binary

Reveals offset FEROS-CORALIE ~35 m/s

Some new results

Starspots model

Launhardt & Setiawan 2005(in preparation)

Some new results

HD 81797 (alpha Hya)

P (MJO) ~ 400 dP (La Silla) ~ 450 d

Some new results

HD 81797 (alpha Hya)

Some new results

Weise & Setiawan 2005(in preparation)

BISECTOR variation Lithium variation

Some new results

Short period oscillationP= 2.9 day

Setiawan, Roth, Weise & Döllinger 2005(in preparation)

2.2m MPG GT(Nov 2004)

Some new results

hours oscillation ?

to be confirmed with HARPS !

minutes oscillation ?

Some new results

Setiawan et al. 2005(submited)

Some new results

secondary orbit ?follow up observationneeded

Some new results

need updated orbital solution

(My) conclusion

G and K giants can show short-term or/and long-term radial velocity variation (in agreement with previous results).

Short-period oscillation : stellar pulsation

Long-period oscillation : rotational modulation or companion

We found various evidences for

• pulsation (at least 2),

• rotational modulation (at least 8)

• as well as substellar companions (at least 3)

in our target sample (~100 stars). However, we need more data to confirm each of these evidences (need successful proposals for ESO time).

Proposed study

• Trend of radial-velocity variability (sigma RV) across the RGB.

• Check chromospheric activity indicator Ca II K (as done for HD 78647).

• Check for special abundance variation (as done for HD 81797).

• Check for bisector variation of special orders (instead of all orders), looking for periodicity solar-like oscillations.

• Search for extra-solar planets around intermediate-mass giants.