SIMBAD references

2010AJ....139.1968E - Astron. J., 139, 1968-1974 (2010/May-0)

Chandra observation of Polaris: census of low-mass companions.

EVANS N.R., GUINAN E., ENGLE S., WOLK S.J., SCHLEGEL E., MASON B.D., KAROVSKA M. and SPITZBART B.

Abstract (from CDS):

We have observed Cepheid Polaris (α UMi A: F7 Ib [Aa] + F6 V [Ab]) with Chandra ACIS-I for 10 ks. An X-ray source was found at the location of Polaris with log LX= 28.89 erg/s (0.3-8 keV) and kT = 0.6 keV. A spectrum this soft could come from either the supergiant or the dwarf, as shown by comparable coronal stars. Two resolved low-mass visual companions, "C" and "D," are not physical members of the system based on the lack of X-rays (indicating an age older than the Cepheid) and inconsistent proper motions. Polaris B is not an X-ray source, consistent with its early F spectral type, and probably does not have a lower mass companion itself. A possible more distant member is identified, and an additional less plausible one. This provides a complete census of companions out to 0.1 pc covering a mass ratio range of an order of magnitude and a ΔV of nearly 15 mag.

Abstract Copyright:

Journal keyword(s): binaries: general - stars: variables: Cepheids - X-rays: stars

Simbad objects: 27

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2021.07.25-04:13:34

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