Rodriguez-Coira, G., Paumard, T., Perrin, G., Vincent, F., Abuter, R., Amorim, A., Bauboeck, M., Berger, J. P., Bonnet, H., Brandner, W., Clenet, Y., de Zeeuw, P. T., Dexter, J., Drescher, A., Eckart, A., Eisenhauer, F., Schreiber, N. M. Forster, Gao, F., Garcia, P., Gendron, E., Genzel, R., Gillessen, S., Habibi, M., Haubois, X., Henning, T., Hippler, S., Horrobin, M., Jimenez-Rosales, A., Jochum, L., Jocou, L., Kaufer, A., Kervella, P., Lacour, S., Lapeyrere, V., Le Bouquin, J. B., Lena, P., Nowak, M., Ott, T., Perraut, K., Pfuhl, O., Sanchez-Bermudez, J., Shangguan, J., Scheithauer, S., Stadler, J., Straub, O., Straubmeier, C., Sturm, E., Tacconi, L. J., Shimizu, T., von Fellenberg, S., Waisberg, I., Widmann, F., Wieprecht, E., Wiezorrek, E., Woillez, J., Yazici, S. and Zins, G. (2021). MOLsphere and pulsations of the Galactic Center's red supergiant GCIRS 7 from VLTI/GRAVITY. Astron. Astrophys., 651. LES ULIS CEDEX A: EDP SCIENCES S A. ISSN 1432-0746

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Abstract

Context. GCIRS 7, the brightest star in the Galactic central parsec, formed 6 +/- 2 Myr ago together with dozens of massive stars in a disk orbiting the central black-hole. It has been argued that GCIRS 7 is a pulsating body, on the basis of photometric variability.Aims. Our goal is to confirm photospheric pulsations based on interferometric size measurements to better understand how the mass loss from these massive stars enriches the local interstellar medium. Methods. We present the first medium-resolution (R = 500), K-band spectro-interferometric observations of GCIRS 7, using the GRAVITY instrument with the four auxiliary telescopes of the ESO VLTI. We looked for variations using two epochs, namely 2017 and 2019. Results. We find GCIRS 7 to be moderately resolved with a uniform-disk photospheric diameter of theta(*)(UD)=1.55 +/- 0.03 mas R-UD(*)=1368 +/- 26 R-circle dot) in the K-band continuum. The narrow-band uniform-disk diameter increases above 2.3 mu m, with a clear correlation with the CO band heads in the spectrum. This correlation is aptly modeled by a hot (T-L = 2368 +/- 37 K), geometrically thin molecular shell with a diameter of theta(L) = 1.74 +/- 0.03 mas, as measured in 2017. The shell diameter increased (theta(L) = 1.89 +/- 0.03 mas), while its temperature decreased (T-L = 2140 +/- 42 K) in 2019. In contrast, the photospheric diameter theta(*)(UD) and the extinction up to the photosphere of GCIRS 7 (A(KS)=3.18 +/- 0.16) have the same value within uncertainties at the two epochs. Conclusions. In the context of previous interferometric and photo-spectrometric measurements, the GRAVITY data allow for an interpretation in terms of photospheric pulsations. The photospheric diameter measured in 2017 and 2019 is significantly larger than previously reported using the PIONIER instrument (theta(*) = 1.076 +/- 0.093 mas in 2013 in the H band). The parameters of the photosphere and molecular shell of GCIRS 7 are comparable to those of other red supergiants that have previously been studied using interferometry. The extinction we measured here is lower than previous estimates in the direction of GCIRS 7 but typical for the central parsec region.

Item Type: Journal Article
Creators:
CreatorsEmailORCIDORCID Put Code
Rodriguez-Coira, G.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Paumard, T.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Perrin, G.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Vincent, F.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Abuter, R.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Amorim, A.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Bauboeck, M.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Berger, J. P.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Bonnet, H.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Brandner, W.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Clenet, Y.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
de Zeeuw, P. T.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Dexter, J.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Drescher, A.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Eckart, A.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Eisenhauer, F.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Schreiber, N. M. ForsterUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Gao, F.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Garcia, P.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Gendron, E.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Genzel, R.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Gillessen, S.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Habibi, M.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Haubois, X.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Henning, T.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Hippler, S.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Horrobin, M.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Jimenez-Rosales, A.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Jochum, L.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Jocou, L.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Kaufer, A.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Kervella, P.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Lacour, S.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Lapeyrere, V.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Le Bouquin, J. B.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Lena, P.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Nowak, M.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Ott, T.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Perraut, K.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Pfuhl, O.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Sanchez-Bermudez, J.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Shangguan, J.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Scheithauer, S.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Stadler, J.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Straub, O.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Straubmeier, C.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Sturm, E.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Tacconi, L. J.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Shimizu, T.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
von Fellenberg, S.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Waisberg, I.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Widmann, F.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Wieprecht, E.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Wiezorrek, E.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Woillez, J.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Yazici, S.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Zins, G.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
URN: urn:nbn:de:hbz:38-605125
DOI: 10.1051/0004-6361/202039501
Journal or Publication Title: Astron. Astrophys.
Volume: 651
Date: 2021
Publisher: EDP SCIENCES S A
Place of Publication: LES ULIS CEDEX A
ISSN: 1432-0746
Language: English
Faculty: Unspecified
Divisions: Unspecified
Subjects: no entry
Uncontrolled Keywords:
KeywordsLanguage
SAGITTARIUS-A-ASTERISK; CENTRAL PARSEC; IONIZED-GAS; YOUNG STARS; PROPER MOTIONS; COOL STARS; ATMOSPHERE; STELLAR; BETELGEUSE; GALAXYMultiple languages
Astronomy & AstrophysicsMultiple languages
URI: http://kups.ub.uni-koeln.de/id/eprint/60512

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