  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Microscopium [1] |
| Right ascension | 20h 46m 20.06779s [2] |
| Declination | −39° 11′ 57.3590″ [2] |
| Apparent magnitude (V) | 5.47±0.01 [3] |
| Characteristics | |
| Evolutionary stage | main sequence [4] |
| Spectral type | B8/9 V [5] |
| B−V color index | −0.10 [6] |
| Variable type | suspected SPB [7] |
| Astrometry | |
| Radial velocity (Rv) | −30±7.4 [8] km/s |
| Proper motion (μ) | RA: +50.451 mas/yr [2] Dec.: −27.196 mas/yr [2] |
| Parallax (π) | 9.9354±0.1022 mas [2] |
| Distance | 328 ± 3 ly (101 ± 1 pc) |
| Absolute magnitude (MV) | +0.49 [1] |
| Details | |
| Mass | 2.83±0.04 [4] M☉ |
| Radius | 2.56±0.13 [9] R☉ |
| Luminosity | 73.5 [10] L☉ |
| Surface gravity (log g) | 4.11±0.14 [11] cgs |
| Temperature | 10,965+255 −250 [12] K |
| Metallicity | 59% solar |
| Metallicity [Fe/H] | −0.23 [13] dex |
| Rotational velocity (v sin i) | 290 [14] km/s |
| Age | 113 [11] Myr |
| Other designations | |
| 23 G. Microscopii [15] , CD−39°13960, CPD−39°8771, FK5 3658, GC 28927, HD 197630, HIP 102497, HR 7933, SAO 212416 [16] | |
| Database references | |
| SIMBAD | data |
HD 197630, also known as HR 7933 or rarely 23 G. Microscopii, is a probable astrometric binary located in the southern constellation of Microscopium. The visible component is a bluish-white hued star that is faintly visible to the naked eye with an apparent magnitude of 5.47. [3] Based on parallax measurements from the Gaia satellite, the system is estimated to be 328 light years away. [2] However, it is drifting closer with a heliocentric radial velocity of −30 km/s . At its current distance, HD 197630's brightness is diminished by 0.11 magnitudes due to interstellar dust. [17] A 2012 multiplicity survey failed to confirm the velocity variations. [18]
HD 197630 has a stellar classification of B8/9 V, [5] indicating that it is a B-type star with the characteristics of a B8 and B9 main sequence star. It has 2.83 times the mass of the Sun [4] and 2.56 times the Sun's radius. It radiates 73.5 times the luminosity of the Sun [10] from its photosphere at an effective temperature of 10,965 K . [12] The star is estimated to be 113 million years old, [11] having completed roughly half of its main sequence lifetime. [4] HD 19730 is spinning rapidly with a projected rotational velocity of 290 km/s . [14]
The object was in a 2002 Hipparcos variability survey and as a result, [20] the AAVSO cataloged HD 197630 as a suspected variable star that fluctuates by 0.005 magnitudes within 7.71 hours. [21] However, subsequent observations have not confirmed this. Further data from the Transiting Exoplanet Survey Satellite suggests that HD 197630 may be a slowly pulsating B-type star plus a variable star with rotation modulations. [7]
